Effects of stretching on muscle strength,endurance,and power performance: A systematic review and meta-analysis

Abstract

BACKGROUND:

The acute and chronic effects of stretching preceding exercises on strength, power and muscular endurance are still not entirely clear in the literature.

OBJECTIVE:

To verify the acute and chronic effects of the main types of stretching (static, dynamic, PNF, and ballistic) on muscle strength, power, and endurance.

METHODS:

A systematic literature search was performed in: PubMed, Web of Science, LILACS, Scopus, Science Direct, and CENTRAL. The methodological quality was assessed using the PEDro scale. Meta-analysis were performed using the standardized mean difference (SMD).

RESULTS:

43 studies were included in the systematic review and 30 in the meta-analysis calculations. Only two studies showed high methodological quality. In general, static stretching had an impact on the potentiated the gain in muscle strength of the lower limbs in the long term (0.60 [0.20–1.00]). The acute (ES $=$ 0.38 [0.05–0.70]) and long-term (ES $=$ 1.04 [0.21–1.88]) dynamic stretching was able to potentiate the gain of muscle power in the lower limbs, while the acute PNF had an impact on the worsening of the muscular endurance (ES $=$ 1.68 [0.83–2.53]).

CONCLUSIONS:

When the training objective is linked to acute effects, dynamic stretching should be prioritized before the main activity. For long-term effects, static and dynamic stretching have been shown to potentiate muscle strength and power gain, respectively, and are recommended in these cases.

Keywords

Young adults performance warm-up meta-analysis

1. Introduction

Stretching is a type of physical exercise with the objective of increasing the range of motion (ROM) of the synovial joints. ROM can be limited by joint structures (capsuloligamentous structures surrounding the joint, joint geometry and congruence) and muscle properties (stiffness, architecture, surrounding fascia, and neuroreflexive properties). Stretching exercises seek to increase muscle extensibility and for that, several techniques have been developed: 1) static, in which the endpoint of the ROM is maintained for a period of time; 2) dynamic, in which the joint is moved repeatedly throughout its ROM; 3) ballistic (dynamic stretching subtype), in which fast and alternating movements are performed through maximum ROM; and 4) pre-contraction, which mainly includes Proprioceptive Neuromuscular Facilitation (PNF), which are characterized by contracting the muscle being stretched or its antagonist prior to performing a static stretch [1].

The practice of stretching is traditionally used as an integral part of warm-up programs performed before various sports activities [2, 3, 4, 5]. For a long time, when performed before the main physical training, static stretching has been considered an effective method for improving performance, preventing injuries, and increasing range of motion [6, 7, 8, 9]. However, a recent systematic review demonstrated that static stretching exercises performed in isolation, with maximum intensity, immediately before training and with a dose greater than 60-s per muscle group, can affect the performance of jumps and sprints [10]. Furthermore, a meta-analysis study including 26,610 participants with 3,464 injuries demonstrated that stretching does not reduce the probability of sports injury [11].

The implementation of the stretching techniques seems to directly impact upon the magnitude of the later responses in muscle strength and power activities, especially regarding the volume and intensity of the application of the exercises [10]. For example, volumes of less than 60-s of static stretching per muscle group and submaximal intensity, that is, just before the point of discomfort, do not seem to harm or improve performance in activities that require maximum muscle strength and power [12, 13, 14, 15, 16]. Furthermore, the time interval between static stretching exercises and subsequent muscle strength and power exercises also appears to play an important role. A decrease in the muscle performance seems to occur if training is performed immediately after stretching [10, 16].

When static stretching is combined with other forms of warm-up, such as low-intensity aerobic exercise prior to static stretching, the negative effects on muscle strength and power performance can be attenuated [17, 18]. However, one study showed that static stretching can have an inhibitory effect on the warm-up benefits provided by aerobic exercise. This is likely due to the effect of stretching on increasing compliance and decreasing muscle stiffness, which in turn affects the interaction between cross-bridges, sarcomere length, and muscle spindle thresholds [19].

Regarding dynamic stretching, its use before the main exercise has been shown to enhance peak strength and muscle power, in addition to improving ROM [10]. A review study demonstrated that the benefits in muscle strength and power provided by dynamic stretching occur when the stretching volume is greater than 90 seconds per muscle group [15]. However, it is still necessary to better investigate the impact of different ways of applying dynamic stretching before muscular strength and power activities, especially with regard to stretching intensity, since it is very difficult to control the intensity of dynamic stretching movements [10]. Furthermore, a question to be answered is whether the improvement in muscle strength and power performance after dynamic stretching is linked to the improvement in ROM or to the heating provided by the movement, which increases body temperature and nerve conduction velocity?

In relation to other forms of stretching, such as proprioceptive and ballistic, there has been few investigations about your impact in the muscle performance. This is because these are techniques that have been little used in clinical practice. Ballistic stretching basically refers to dynamic stretching with greater intensity. On the other hand, in PNF there is a process of intense isometric contraction, preceding intense static support at the greatest joint range. Review studies [10, 20] demonstrated that proprioceptive neuromuscular facilitation (PNF) stretching tends to impair the performance of muscle strength and power, while for ballistic stretching no comparisons were found. Another limitation of the literature is that few studies have addressed the effects of stretching on muscle endurance. Although some previous systematic review studies have addressed this issue [21, 22, 23], little has been discussed about the different application variables of the stretching subtypes on muscle strength, power, and endurance performance through quantitative analysis. Thus, the aim of this study was to conduct a systematic search in the literature and statistical procedure of meta-analysis, to verify the effects of different forms of stretching on the muscle performance (strength, endurance, and power).

2. Methods

This research is characterized as a systematic review and meta-analysis [24, 25], which was reported in accordance with the recommendations of the PRISMA protocol [26]. Considering that this study aimed to evaluate an outcome more related to sports performance, but not a health outcome directly, a protocol in PROSPERO is not required and therefore it was not carried out (crd.york.ac.uk/prospero/#guidancenotes). Inclusion criteria were: (a) randomized controlled clinical trials (RCTs), which investigated the effects of stretching on muscle strength, power, and/or endurance in young adults (there was no restriction on ethnicity, level of physical activity, sex, or period of intervention).

Exclusion criteria were: (a) study designs that were not RCTs; (b) non-use of stretching exercises or that associated stretching exercises with another form of intervention; (c) stretching exercises not associated with muscle strength, endurance, or power as a form of evaluation; (d) studies that performed the intervention with adolescent volunteers ( $\leqslant$ 18 years), middle-aged or older adults ( $\geqslant$ 45 years); (e) studies with information duplicated in another RCT; (f) young adults who had a pathological condition or secondary causes of alterations in muscle strength.

2.1 Databases and search strategy

The search was performed in the following databases: PubMed, Web of Science, LILACS, Scopus, Science Direct, and CENTRAL (The Cochrane Library), without using a filter that limited the date of publication or language. Searches in clinical trial registration databases (clinicaltrials.gov and apps.who.int/trialsearch) were also carried out in order to find unpublished studies. The final search took place on August 15, 2023.

As a search strategy, the following keywords were selected: (“adult*” OR “athlete*”) AND (“muscle stretching exercises” OR “stretching” OR “static stretching” OR “passive stretching” OR “static passive stretching” OR “isometric stretching” OR “active stretching” OR “static active stretching” OR “ballistic stretching” OR “dynamic stretching” OR “proprioceptive neuromuscular facilitation” OR “PNF” OR “flexibility” OR “mobility training”) AND (“muscle strength” OR “muscle strength dynamometer” OR “strength*” OR “power” OR “muscle power” OR “muscular endurance” OR “power performance” OR “strength performance” OR “muscular resistance”). The search for each word was left in all fields, in order to increase sensitivity and decrease precision.

2.2 Selection of studies

One reviewer (RGO) performed the initial search strategy in the databases, extracting titles and abstracts. Subsequently, the selection of studies, evaluation, and data extraction were carried out blindly by two authors (ALR and AYVS). Initially, the screening was carried out based on the reading of titles and abstracts. Potentially eligible articles were read in full. A manual search was performed in the reference lists of all eligible articles, in an attempt to find new references. Disagreements, when unresolved between the two researchers, were transmitted to a third researcher (RGO) who decided on the issue. The same form for data extraction was used by all authors.

The PICO method [27] was used to structure the bibliographic search and data extraction: P (population) $=$ young adults; I (intervention) $=$ stretching exercise (static, dynamic, proprioceptive, or ballistic); C (comparison) $=$ no intervention or other form of stretching; O (outcome) $=$ muscle strength, endurance, and/or power.

2.3 Data extraction

The following data were extracted from each study: a) name of the first author, year of publication, and location; b) number of volunteers allocated to each group; c) type of activity or level of physical activity; d) mean and standard deviation of age in each group; e) study duration, weekly frequency, time of each session or/and set, interval time between each set, control group activity, time and type of warm-up exercise; e) type of stretching used (static, dynamic, PNF, and ballistic), muscle group involved, accessories used, stretching intensity; f) instrument for assessing muscle strength, power, or endurance; g) results reported for muscle strength, power, or endurance in the comparison between groups ( $p<$ 0.05).

2.4 Assessment of the methodological quality of studies

The methodological quality was assessed using the PEDro scale (Physiotherapy Evidence Database) [28, 29] through the score available in the database (www.pedro.org.au/search). When the study was not classified in the PEDro database, two independent reviewers (ALR and AYVS) performed the classification. A third reviewer (RGO) was requested in case of disagreement. The PEDro scale takes into account the internal validity and adequacy of statistical information from the studies, and has 11 questions, with three items from the Jadad scale [30] and nine items from the Delphi list [31]. The first question is not scored (related to the external validity of the study), and the other ten questions are scored. Each item that meets the required criteria receives a point, allowing the classification of the quality of each study: excellent (9–10), good (6–8), fair (4–5), or poor ( $<$ 4). Studies with a score $\geqslant$ 6 were considered to be of high quality. Maher et al. [28] demonstrated good inter-rater reliability, with an intra-class correlation coefficient of 0.68 when using consensus ratings, generated by two or three independent raters on the PEDro scale. No study was excluded for its methodological quality score, however, the score was considered in the interpretation of results and discussion of findings.

2.5 Definitions

Four types of stretches were considered in this systematic review: static, dynamic, PNF, and ballistic. Regarding the outcomes, the following were considered: strength, power and muscular endurance. The definition for each exposure and outcome variable will be presented below.

2.5.1 Static stretching

In static stretching, the greatest range of joint motion is maintained for a given period of time, so that the stretched muscles remain under tension. Static stretching can be performed actively or passively. In active static stretching, the point of greatest joint amplitude or muscle discomfort is maintained by the subject performing the stretching. On the other hand, in passive static stretching, a partner moves the body segment to the point of greatest amplitude and is in charge of maintaining this position until the pre-established time [1]. Normally, in static stretching, the position of greatest joint amplitude is maintained for a period of 15 to 30-s per set (which totals approximately 60-s depending on the number of sets of the exercise), contributing to greater control in the execution, since it is performed without speed, with little or no movement [7]. Acute static stretching can produce changes in the length and stiffness of the muscle-tendon unit (MTU) of the segment involved, that is, acute stretching temporarily modifies the elastic components [32]. For this reason, it has been used frequently before sports activities as it contributes to the ability to stretch or reach during the activity, as a consequence of the decrease in the resistance of a less rigid muscle to the intended movement [33, 34].

2.5.2 Dynamic stretching

Dynamic stretching is the act of moving a joint seeking the maximum amplitude possible, without maintaining the segment at the point of greatest amplitude, returning to the initial position, with little resistance. The movement can incorporate sport-specific movements when the goal is to prepare athletes for a sport activity [35]. It is believed that this type of stretching is related to the physiological mechanisms involved in temperature rise, nerve conduction velocity and/or central impulse, enzyme cycle, energy production, and changes in muscle compliance [35]. The frequency of dynamic stretching per unit of time (specific durations, number of sets and repetitions) and the perceived intensity per amplitude can contribute to establishing warm-up protocols with dynamic stretching.

2.5.3 Proprioceptive neuromuscular facilitation

Among the forms of stretching, the literature demonstrates that PNF is the most effective method for increasing range of motion [36, 37]. PNF involves both a passive and an active component. The movement is conducted by first assuming an initial passive stretch, followed by an isometric contraction performed for approximately 15 to 25-s. After contraction, the muscle is relaxed for 2 to 3-s and then immediately subjected to a passive stretch. Isometric contraction fatigues the muscle fiber mechanical receptors (muscle spindles), allowing for a deeper stretch, resulting in greater gains in range of motion [7].

2.5.4 Ballistic stretching

Ballistic stretching is a rapid, oscillating movement in which the segment to be stretched is set in motion through a progressive range, until the muscles are stretched at the joint limit [38]. One of the differences inherent in this type of stretching is observed in the intensity of activation of the motor unit during ballistic movements, which is greater than during slower movements performed in static stretching, for example. Slower stretching movements exhibit continuous agonist activity, whereas ballistic movements are characterized by alternating bursts of agonist and antagonist activity, which promote greater neuromuscular adaptations such as reflex reactions [39]. One of the characteristics of ballistic stretching is the increase in range of motion obtained through an abrupt series of large movements, which increases susceptibility to muscle strain injuries.

2.5.5 Strength, power and muscular endurance

Regarding outcomes, muscular strength was defined as the ability of the musculoskeletal system to exert maximum force, such as in one repetition maximum tests, hand grip or isokinetic dynamometry. Muscular power was defined as the ability to perform a certain movement involving simultaneously strength and speed, as occurs, for example, in the vertical jump test, throws or sprints. With regard to muscular resistance, the definition referred to the ability of the musculoskeletal system to perform muscular work for several repetitions or prolonged time, as occurs in tests that aim to identify the maximum number of repetitions in 30 seconds, for example [40].

2.6 Synthesis of results

For meta-analysis, the measure of effect was the standardized mean difference (SMD) between the comparison groups in muscle strength, power, and endurance performance at the post-intervention time. The Cochrane Q test for heterogeneity was performed and considered statistically significant if $p\leqslant$ 0.10. Heterogeneity was also quantified with the I² statistic, where 0–40% may not be important, 30–60% may represent moderate heterogeneity, 50–90% may represent large heterogeneity, and 75–100% is defined as considerable heterogeneity [41]. Fixed effects models were used when there was no statistically significant heterogeneity, otherwise random effects models were used.

It was not possible to perform sensitivity analysis due to the small number of studies with satisfactory methodological quality. Subgroup analyses were performed for: type of stretch (static vs. dynamic; static vs. PNF); exercise dose response (volume $\geqslant$ 60-s vs. $<$ 60-s for static stretching [13]; volumes $\geqslant$ 90-s vs. $<$ 90-s for dynamic stretching) [9]; exercise intensity (low vs. high); performance evaluation moment (immediate vs. longer after the intervention); intervention after aerobic warm-up (with warm-up vs. no warm-up).

Values referring to the effect of stretching were only considered statistically significant when $p<$ 0.05. Effect sizes (ES) were interpreted as proposed by Cohen [42], being considered $<$ 0.2 trivial, 0.2–0.39 small, 0.4–0.69 moderate, and $\geqslant$ 0.7 large magnitude. In the analyses where there were $\geqslant$ 10 studies, a funnel plot was generated to assess the risk of publication bias. All analyses were performed using the Review Manager program (RevMan) [Computer program], version 5.4, Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration.

3. Results

3.1 Qualitative synthesis of studies

Figure 1.

PRISMA flowchart presenting the summary of searches carried out in the literature.

Initially, 7,631 potentially relevant titles and abstracts were identified. After removing the duplicates, the titles and abstracts of 5,341 studies were read, of which 5,074 that did not meet the eligibility criteria were excluded. Therefore, 267 reports were searched, of which 15 did not have a full text available. In this way, 252 reports were read in full, of which 209 did not meet the inclusion criteria. The main reason for exclusion was the study design, not an RCT (98 studies), followed by age (82 studies); studies with information duplicated in another RCT (12 studies); studies that did not use any type of stretching as an intervention (8 studies); and studies that did not measure muscle strength, power, or endurance (9 studies). Thus, 43 studies remained in the systematic review and 30 studies had enough information for meta-analysis (Fig. 1).

The randomized controlled trials included in this systematic review were published between the years 2006 and 2023, and a total of 974 participants (ranging from 9 [43] to 57 [13]). The groups in each study ranged from two [13, 44, 45, 46, 47, 48, 49, 50, 51] to six [52], with a mean age of volunteers between 20 [53] and 34 years [5]. Thirty-six studies performed stretching as an acute intervention [2,4,5,13,16,39,43,44,45,48,49, 50,51,52,53,54,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74] and seven studies included the long-term stretching intervention [46, 47, 75, 76, 77, 78, 79]. Thirty studies performed active stretching [2,4,5, 43,44,46,47,48,49,50,52,53,55,56,57,58,59,60,61,62,63,66,67,70,71,73,74,76,78,79] and 12 performed passive stretching [13, 16, 39, 45, 51, 54, 64, 65, 68, 69, 72, 77]. Only one study did not report whether stretching was performed actively or passively [75]. Some studies used accessories during stretching interventions, such as straps, the wall or a support bar, platform without vibration, raised platform, intensity tester for stretching, bench, inclined board, metronome, support for foot support, isokinetic equipment [4, 39, 44, 48, 49, 58, 59, 62, 63, 67, 77, 78, 79].

In acute intervention studies, the time for each stretch ranged from 15-s [60] to 120-s [39, 68, 48]. As for studies with long-term interventions, the total time for each stretch ranged from 28 [76] to 300-s in each session [77, 79]. The weekly frequency ranged from three [46, 47, 75, 78, 79] to five times [76] per week, while the total intervention time ranged from four [77, 78] to eight weeks [75, 76].

Twenty-three studies performed an aerobic warm-up before the intervention [2, 5, 13, 39, 44, 50, 52, 53, 55, 57, 59, 60, 61, 62, 63, 65, 66, 67, 68, 70, 73, 74, 75] and 18 studies [4, 16, 43, 45, 46, 47, 48, 49, 51, 54, 56, 58, 64, 69, 71, 72, 76, 77] did not. Of the studies included in the review, 37 performed static stretching, 15 dynamic stretching, 6 PNF and 6 ballistic stretching. The time interval between the stretching intervention and the assessment of muscle strength, endurance, or power varied from immediately in 13 studies [4, 5, 13, 16, 44, 50, 51, 52, 53, 57, 58, 73, 76] to 60 minutes for one study [68]. Seven studies did not report the time interval between the intervention and assessment [47, 56, 59, 64, 67, 69, 72].

A total of 21 studies used a second intervention group, involving different types of stretching (static, dynamic, PNF, or ballistic) or other forms of warm-up, such as isolated aerobic, jumps, and sprints [2, 5, 16, 43, 44, 53, 56, 57, 58, 61, 62, 63, 64, 66, 67, 69, 70, 71, 72, 75, 76]. Eleven studies used more than two intervention groups, involving different types of isolated stretches, associated with each other or with other forms of warm-up, such as: massage, aerobic, foam roller, vibration, jumps, and sprints [4, 39, 52, 55, 59, 60, 65, 68, 69, 73, 74]. Seventeen studies included a control group that maintained the usual routine [4, 16, 43, 45, 46, 47, 48, 49, 51, 54, 56, 58, 64, 69, 71, 72, 77, 76, 81]. The other studies performed aerobic warm-up or another type of dynamic warm-up during the intervention period [2, 5, 13, 39, 44, 50, 52, 53, 55, 57, 59, 60, 61, 62, 63, 65, 66, 67, 68, 70, 73, 74].

Muscle strength measurements were performed mainly for the lower limbs, through: concentric isokinetic peak moment [62, 66]; concentric isokinetic peak torque [48, 49, 53, 57, 67, 70, 75, 77], or concentric and eccentric [45]; maximal voluntary isometric muscle contraction in the isokinetic [46, 47, 77, 78], or the extensor chair [58]; peak eccentric force on the multi-joint dynamometer [60]; one repetition maximum (1 RM) [56, 71] or 3 $\times$ 12 RM at 60–80% in the leg press [43]. An exception was an assessment for upper limb strength using a hand grip dynamometer [13] and another with a custom testing device [79]. Muscle power measures were:; sprint test [4, 52, 58, 76], eccentric peak power in multiarticular isokinetics [60]; peak power in vertical jump obtained by time of flight on a contact mat [16]; concentric power in uniarticular isokinetics for knee extensors [48, 49, 64, 65]; vertical jump height [2, 4, 5, 16, 39, 44, 47, 50, 51, 52, 54, 55, 57, 58, 59, 63, 68, 70, 73, 74, 76]. The measures of muscular endurance were: number of repetitions at 40, 60, and 80% of 1 RM in the bench press and for knee extensors [72]; number of repetitions at 85% of 1 RM [69]; and 35 m sprint test [61].

Regarding the reported results, 18 RCTs found no differences between the types of stretching and control groups [2, 4, 5, 39, 44, 45, 46, 47, 54, 56, 57, 58, 59, 60, 61, 62, 63, 77, 78, 79]. With respect to the worsening of performance for muscle strength, six studies [43, 48, 53, 66, 67, 71] verified a significant effect for the decline in the performance of lower limbs after performing static stretching compared to the control group. The decrease in the time to concentric peak torque of knee extensors was verified in one study [49] after performing dynamic stretching. One study [13] found a significant effect for the decline in the performance of maximum isometric muscle strength in the wrist flexor manual dynamometer after performing static stretching. Novaes et al. [43] verified a decrease in muscle strength in the 3 $\times$ 12 RM assessments at 60–80% of knee extensors and flexors and plantar flexors after performing the PNF stretch. In relation to muscle endurance, Franco et al. [69] found a significant decrease in the bench press exercise at 85% of 1 RM, after performing static stretching. Studies [69, 72] also found a significant effect for the decline in the muscular endurance of the upper limbs in the bench press exercise at 85% and 60–80% of 1 RM after PNF, respectively. A study by Gomes et al. [72] also found a decline in muscle endurance of knee extensors at 40, 60, and 80% of 1 RM. For lower limb muscle power assessed by vertical jump, significant effects were found for performance decline after static stretching in five studies [16, 50, 55, 68, 70]. Vertical jump performance also declined significantly after PNF and ballistic stretching [68, 70], respectively.

Regarding performance improvement compared to control groups, four studies [49, 64, 74, 76] found a significant effect for improved lower limb muscle power assessed by vertical jump, after dynamic stretching, and two studies after performing static stretching [48, 51]. One study [75] found a significant effect for improving the concentric muscle strength of lower limbs in the isokinetic assessment after static stretching and PNF.

When comparing the types of stretching, significant effects were verified in favor of: static stretching vs. PNF, for lower limb muscle endurance at 60–80% of 1 RM [72]; ballistic stretching vs. static stretching for lower limb muscle strength in the 1 RM leg press test [71]; dynamic stretching vs. static stretching for concentric isokinetic peak torque of knee extensors and flexors [67]; static stretching vs. PNF, for muscle endurance of lower [43] and upper [69] limbs evaluated by the 3 $\times$ 12 RM test at 60–80% of 1 RM and 85% of 1 RM, respectively; dynamic stretching vs. static stretching, for vertical jump height [73] and concentric power of knee extensors in the isokinetic assessment; dynamic stretching vs. PNF, for muscle power of knee extensors [65]; dynamic stretching associated with static vs. isolated static stretching for vertical jump height [73]; dynamic stretching associated with dynamic warm-up vs. isolated static stretching for vertical jump height [52].

Twelve studies [2, 44, 52, 54, 55, 57, 58, 64, 67, 68, 75, 77] reported participants’ compliance with the intervention, which was always above 85%. Of these studies, two were of long-term intervention [77, 81]. No studies reported adverse events.

3.2 Methodological quality of studies

Table 1
Methodological quality of the studies included in the systematic review

Authors

Eligibility criteria

Random allocation

Concealed allocation

Baseline comparability

Blind subjects

Blind therapists

Blind assessor

Adequate follow-up

Intention-to-treat analysis

Between-group comparisons

Point estimates and variability

Score

Knudson et al. 2005

Yes

Papadopoulos et al. 2005

Yes

Yamaguchi et al. 2005

Yes

Yamaguchi et al. 2006

Yes

Behm et al. 2007

Yes

Brandenburg et al. 2007

Yes

Bradley et al. 2007

Yes

Vetter et al. 2007

Yes

Yamaguchi et al. 2007

Yes

Beedle et al. 2008

Yes

Franco et al. 2008

Yes

Jagger et al. 2008

Yes

Manoel et al. 2008

Yes

Samuel et al. 2008

Yes

Bacurau et al. 2009

Yes

Chen et al. 2009

Yes

Curry et al. 2009

Yes

La Torre et al. 2010

Yes

Winke et al. 2010

Yes

Gomes et al. 2011

Yes

Aguilar et al. 2012

Yes

Morrin et al. 2013

Yes

Fortier et al. 2013

Yes

Konrad et al. 2014

Yes

Pinto et al. 2014

Yes

Turki-Belkhiria et al. 2014

Yes

Novaes et al. 2015

Yes

Rodrigues et al. 2016

Yes

Souza et al. 2016

Yes

Yang et al. 2017

Yes

Walsh et al. 2017

Yes

Harmanci et al. 2017

Yes

Krcmar et al. 2017

Yes

Alp et a. 2018

Yes

Gao et al. 2018

Yes

Smith et al. 2018

Yes

Barbosa et al. 2019

Yes

Yildiz et al. 2020

Yes

Nakao et al. 2021

Yes

Ikeda et al. 2021

Yes

Júnior-Solon et al. 2021

Yes

Nakamura et al. 2021

Yes

Reiner et al. 2023

Yes

Table 1 demonstrates the methodological quality of the studies according to the PEDro scale. Only two studies [2, 54] achieved a score $\geqslant$ 6 and were therefore classified as having high methodological quality. Thus, the other studies achieved scores $<$ 6 and were considered of low methodological quality [4,5,13,16,39,43,44,45, 46,47,48,49,50,51,52,53,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77]. The mean methodological quality score of the 43 studies included in the systematic review was 3.9 points on the PEDro scale.

3.3 Quantitative synthesis of studies (meta-analysis)

3.3.1 Primary analysis: Acute effects of stretching

Table 2
Primary analysis: acute effects of stretching on muscle strength, power and endurance

Static stretching vs. control
	ES	CI [95%]	$P$	$N$ (studies)	I²
Strength	0.25	$-$ 0.04 to 0.53	0.09	192 (6)	0%
Endurance	0.04	$-$ 0.68 to 0.76	0.91	30 (1)	–
Power	0.15	$-$ 0.03 to 0.33	0.09	497 (15)	0%
Dynamic stretching vs. control
Strength	0.16	$-$ 0.19 to 0.51	0.38	126 (4)	0%
Power	0.38	0.05 to 0.70	0.02^#	270 (9)	40%
PNF vs. control
Endurance^*	1.32	0.75 to 1.88	$<$ 0.00001^†	60 (2)	0%
Endurance	1.68	0.83 to 2.53	0.0001^†	30 (1)	–
Power	0.09	$-$ 0.71 to 0.89	0.83	24 (1)	–
Balistic stretching vs. control
Power	0.15	$-$ 0.73 to 1.03	0.74	20 (1)	–
Static stretching vs. dynamic stretching
Strength	0.02	$-$ 0.33 to 0.37	0.92	126 (4)	0%
Power	0.42	0.01 to 0.83	0.04^#	226 (7)	54%
Static stretching vs. PNF
Endurance	1.64	0.80 to 2.48	0.0001^‡	30 (1)	–
Power	$-$ 0.06	$-$ 0.86 to 0.74	0.88	24 (1)	–
Dynamic stretching vs. PNF
Power	0.28	$-$ 0.53 to 1.08	0.50	24 (1)	–

PNF: proprioceptive neuromuscular facilitation; ES: effect size; CI: Confidence interval; I²: Heterogeneity; –: Heterogeneity not applicable; $N$ : sample; ^#favors dinamic stretching; ^†favors control; ^‡favors static stretching. Note: all comparisons involved lower limbs, unless otherwise indicated: ^*upper limbs.

Table 2 presents a primary analysis involving the acute effects of stretching on muscle strength, power, and endurance. Only one analysis involved the upper limbs, demonstrating a large effect size for decreasing muscle endurance after PNF (ES $=$ 1.32). All other analyses were for lower limbs. In this case, compared to control groups, no significant results were observed in comparisons involving static and ballistic stretching. Dynamic stretching potentiated the increase in muscle power ( $p=$ 0.02), with a small effect size (ES $=$ 0.38), with no difference for muscle strength. PNF caused a decline in muscle endurance, with a large effect size (ES $=$ 1.68), with no difference for muscle power. Comparing the different forms of stretching with each other, there was a significant difference in favor of dynamic stretching compared to static stretching for muscle power, with a moderate effect size (ES $=$ 0.42), but not for strength, while static stretching was superior to PNF for muscle endurance with a large effect size (ES $=$ 1.64), but not for power. Finally, dynamic stretching was not different from PNF for muscle power.

3.3.2 Primary analysis: Chronic effects of stretching

Table 3
Primary analysis: chronic effects of stretching on muscle strength, power and endurance

Static stretching vs. control
	ES	CI [95%]	$P$	$N$ (studies)	I²
Strength	0.60	0.20 to 1.00	0.004^‡	102 (4)	0%
Strength^*	0.66	0.00 to 1.32	0.05	38 (1)	–
Endurance	0.06	$-$ 0.73 to 0.84	0.89	25 (1)	–
Power	0.37	$-$ 0.42 to 1.16	0.36	25 (1)	–
Dynamic stretching vs. control
Power	1.04	0.21 to 1.88	0.01^#	26 (1)	–
PNF vs. control
Strength	0.45	$-$ 0.44 to 1.34	0.32	20 (1)	–
Balistic stretching vs. control
Strength	0.01	$-$ 0.62 to 0.63	0.99	39 (1)	–

PNF: proprioceptive neuromuscular facilitation; ES: effect size; CI: Confidence interval; I²: Heterogeneity; –: heterogeneity not applicable; $N$ : sample; ^#favors dinamic stretching; ^‡favors static stretching. Note: all comparisons involved lower limbs, unless otherwise indicated: ^*upper limbs.

Table 3 presents a primary analysis involving the chronic effects of stretching on lower limb muscle strength, power, and endurance. Static stretching potentiated the increase in muscle strength, with a moderate effect size (ES $=$ 0.60), but not for endurance and power. Dynamic stretching potentiated muscle power gain, with a large effect size (ES $=$ 1.04). PNF and ballistic stretching were not different from the control group. The only analysis involving upper limbs did not identify significant effects for muscle strength after intervention with static stretching.

3.3.3 Subgroup analysis

Table 4
Subgroups analysis: acute effects of static stretching vs. control on muscle strength, power

Muscle strength
		ES	CI [95%]	$P$	$N$ (Studies)	I²
Volume	$\geqslant$ 60-s	0.43	0.03 to 0.83	0.04^†	98 (3)	0%
	$<$ 60-s	0.04	$-$ 0.32 to 0.39	0.84	124 (4)	0%
Intensity	Low	0.08	$-$ 0.41 to 0.57	0.76	64 (2)	0%
	High	0.33	$-$ 0.02 to 0.67	0.06	132 (4)	0%
Aerobic heating	Performed	0.34	$-$ 0.01 to 0.69	0.06	128 (4)	0%
	Absent	0.07	$-$ 0.40 to 0.55	0.76	68 (2)	0%
Evaluation time	Immediate	0.05	$-$ 0.45 to 0.56	0.83	60 (2)	0%
	Late	0.43	0.03 to 0.83	0.04^†	98 (3)	0%
Muscle power
Volume	$\geqslant$ 60-s	0.12	$-$ 0.14 to 0.37	0.38	234 (8)	0%
	$<$ 60-s	0.08	$-$ 0.17 to 0.32	0.55	251 (8)	0%
Intensity	Low	0.36	0.09 to 0.63	0.008^†	217 (6)	0%
	High	0.03	$-$ 0.23 to 0.30	0.79	228 (8)	0%
Aerobic heating	Performed	0.18	$-$ 0.03 to 0.39	0.10	343 (9)	0%
	Absent	0.09	$-$ 0.23 to 0.40	0.60	154 (6)	0%
Evaluation time	Immediate	0.02	$-$ 0.22 to 0.27	0.86	254 (8)	0%
	Late	0.38	0.11 to 0.64	0.006^†	221 (6)	0%

ES: effect size; CI: Confidence interval; I²: Heterogeity; $N$ : sample; ^†favors control. Note: all comparisons involved lower limbs.

Table 4 presents the subgroup analysis involving the acute effects of static stretching vs. control over muscle strength and power of lower limbs. Static stretching decreased muscle strength performance, with a moderate effect size (ES $=$ 0.43), when applied with a volume $\geqslant$ 60-s and when evaluated later (mean 5 min after stretching), as well as, for muscle power, with a small effect size when performed at low intensity (ES $=$ 0.36) and when assessed later (ES $=$ 0.38) (mean 4 min after stretching). For all other variables there were no differences between groups.

Table 5 presents the subgroup analysis involving the acute effects of dynamic stretching vs. control over muscle strength and power of lower limbs. Dynamic stretching potentiated muscle power gain when performed at a volume $<$ 90-s, with a small effect size (ES $=$ 0.34). For all other variables there were no differences between groups.

4. Discussion

The current study aimed to verify the effects of different forms of stretching on the performance of muscle strength, endurance, and power through a systematic review and meta-analysis. In the current study we only included RCTs, which decreases the risk of bias in our analyses. In order to increase the homogeneity of the sample, we limited the age range to young adults, which typically refers to the public with the greatest interest in research related to performance gains in muscle strength, endurance, and power.

4.1 Agreements and disagreements with other studies

4.1.1 Effects of static stretching on muscle strength, endurance, and power performance

Regarding static stretching, performed acutely, prior tosports activities, a substantial number of articles did not identify any harmful effect on the performance of muscle strength and power [2, 4, 5, 39, 44, 45, 46, 54, 56, 57, 58, 59, 60, 61, 62, 63]. However, a systematic review study demonstrated that static stretching exercises can impair strength and muscle power gain when performed in isolation (without another form of associated warm-up) and when performed for a long time ( $\geqslant$ 60-s per muscle group) [10]. In addition, other factors related to static stretching that can affect the performance of muscle strength and power were demonstrated: high intensity stretching and immediate post-intervention evaluation (less than 5 min) [10, 15]. That is, when stretching is performed in the maximum discomfort zone and the assessment of muscle strength/power occurs immediately after stretching exercises.

Table 5
Subgroups analysis: acute effects of dynamic stretching vs. control on muscle strength, power

Muscle strength
		ES	CI [95%]	$P$	$N$ (Studies)	I²
Volume	$\geqslant$ 90-s	0.30	$-$ 0.19 to 0.79	0.23	66 (2)	43%
	$<$ 90-s	0.00	$-$ 0.50 to 0.51	0.99	60 (2)	0%
Intensity	Low	0.10	$-$ 0.62 to 0.81	0.79	30 (1)	–
	High	0.06	$-$ 0.42 to 0.54	0.80	68 (2)	0%
Aerobic heating	Performed	0.29	$-$ 0.49 to 1.07	0.47	58 (2)	55%
	Absent	0.06	$-$ 0.42 to 0.54	0.80	68 (2)	0%
Evaluation time	Immediate	0.00	$-$ 0.50 to 0.51	0.99	60 (2)	0%
	Late	0.70	$-$ 0.07 to 1.47	0.07	28 (1)	–
Muscle power
Volume	$\geqslant$ 90-s	0.19	$-$ 0.62 to 0.99	0.65	24 (1)	–
	$<$ 90-s	0.41	0.05 to 0.77	0.03^#	246 (8)	47%
Intensity	Low	0.46	$-$ 0.27 to 1.19	0.21	30 (1)	–
	High	0.26	$-$ 0.14 to 0.66	0.20	98 (3)	0%
Aerobic heating	Performed	0.24	$-$ 0.05 to 0.52	0.10	194 (6)	0%
	Absent	0.74	$-$ 0.31 to 1.79	0.17	76 (3)	78%
Evaluation time	Immediate	0.22	$-$ 0.10 to 0.54	0.18	152 (5)	0%
	Late	0.24	$-$ 0.16 to 0.64	0.24	96 (3)	0%

ES: effect size; CI: Confidence interval; I²: Heterogeity; –: heterogeity not applicable; $N$ : sample; ^#favors dinamic stretching. Note: all comparisons involved lower limbs.

The present study also identified that static stretching was shown to be harmful to muscle strength gain when performed with a volume $\geqslant$ 60-s per muscle group. On the other hand, contradicting the literature [10, 15], a harmful effect was observed when evaluated on average 5 min post-intervention for muscle strength and power performance and when performed at low intensity for muscle power. It is probable these results may have been influenced by the volume of stretching, considering that in these analyses involving intensity and time of assessment, most studies had a volume $\geqslant$ 60-s per muscle group. Furthermore, it must be considered that the harmful effects observed were of small magnitude. However, according to our findings, when compared to other forms of stretching such as PNF, this type of stretching seems to be a viable stretching option before muscular endurance performance (ES 1.64, Table 2).

With regard to chronic interventions, our analyses demonstrated a moderate effect size in favor of static stretching to increase muscle strength. This is probably due to a possible long-term benefit of static stretching over muscle hypertrophy, thereby contributing to increased muscle strength [82]. A recent review study demonstrated that these effects may be dependent on greater overload in the execution, such as the aid of equipment or external load [83]. Considering the follow-up time of studies with a chronic intervention included in our analysis (6 and 8 weeks), it is noteworthy that they are located close to the minimum time (8 weeks) suggested for morphological alterations in elastic structures to be noticeable [84, 85]. In addition, studies excluded from our analyses for not meeting the inclusion criteria also found positive effects of long-term static stretching on strength performance [81, 86, 87, 88].

4.1.2 Effects of dynamic stretching on muscle strength and power performance

In the context of dynamic stretching, in our primary analysis, we identified that performing this technique acutely pre-training provided significant improvement in lower limb muscle power performance when compared to the control condition or static stretching, with small and moderate effect sizes, respectively. Taking into consideration the primary analysis with chronic interventions, dynamic stretching provided an increase in lower limb muscle power compared to the control group, with a high effect size. The isolated effect of chronic dynamic stretching had not been investigated in any previous meta-analysis work.

Regarding the mechanisms by which dynamic stretching can improve muscle performance, the following hypotheses have been suggested: increase in muscle and body temperature [35]; increased neuromuscular function, caused by post-activation potentiation in the elongated muscle, through voluntary contractions of antagonist muscles, which supposedly contributes to greater cross-bridge formation of actin and myosin filaments [89, 90]; stimulation of the nervous system and/or decreased inhibition of antagonist muscles [5, 64]; and decreased muscle stiffness; increased metabolic rate related to phosphorylation of regulatory myosin light chains and glycolytic energy systems that improve actin-myosin interaction [74, 91, 92, 93]. Through these mechanisms, dynamic stretching can improve muscle strength and power development [64, 89, 90]. Although these mechanisms have been hypothesized by the literature so far, it must be considered that dynamic stretching, due to the nature of the movements/exercise performed, can generate effects similar to warm-up. That is, the effects on the subsequent performance of strength, power and muscular endurance can be basically linked to the muscular warm-up [35].

Subgroup analyses also found significant effects for improving lower limb muscle power when dynamic stretching was performed with a volume $<$ 90-s per muscle group, with a small effect size. This result is divergent from the findings of previous studies [89, 94], in which only larger volumes of dynamic stretching potentiated muscle power performance. Although a systematic review study [10] has shown that both volumes $\geqslant$ 90-s and volumes $<$ 90-s of dynamic stretching potentiated the gain in muscle power and strength, with an advantage for larger volumes, in the present study, volumes $\geqslant$ 90-s of dynamic stretching did not show any effect on muscle strength and power. This could perhaps be explained by the fact that the analysis with a volume $\geqslant$ 90-s was carried out with a single study, while the analysis with a volume $<$ 90-s included eight studies.

When analyzing studies according to the intensity of dynamic stretching (low or high), no significant results were found. Dynamic stretching studies are often inconsistent in their description of intensity, making this comparison difficult. Although some studies do not report intensity [49, 52, 62, 64, 65], others control the intensity of dynamic stretching by reporting the range of motion achieved or the point of joint discomfort [2, 56, 57, 58, 73, 76]. However, other factors must also be considered, such as the frequency and speed of movement, which seem to have a direct impact on the modulation of muscle power and strength performance [10, 71, 95].

In the current work, no significant results for muscle strength and power performance were observed when dynamic stretching was preceded or not by aerobic warm-up exercises and when evaluated immediately or after an average period of 4 minutes. It seems that the greater concern with these factors in the warm-up program is more evident when considering other forms of stretching, such as static and PNF. It is noteworthy that dynamic stretching did not have a negative influence on the performance of power and muscle strength in any of our analyses.

4.1.3 Effects of PNF on the performance of muscle strength, endurance, and power

For PNF, in the present study, an analysis that verified its acute effect on the muscular resistance of upper and lower limbs, showed that this form of pre-training stretching significantly decreases the number of repetitions in the bench press and knee extension exercises, with a large effect size. This effect of PNF apparently only affects resistance capacity, since changes were not observed for muscle power. PNF, according to previous studies [68, 80, 81, 96, 97] is a technique that has a greater capacity to lead to gains in range of motion, when compared to other forms of stretching, producing a great capacity for transient changes, such as reduced muscle stiffness and lower motor unit recruitment [80, 98]. Thus, its effects can last for a longer period after its application [80], which could eventually compromise muscle contraction and the musculature’s ability to resist external loads. This can be explained by the effect of PNF stretching on the body’s mechanoreceptors, such as: the neuromuscular spindle and Golgi tendon organ (GTO).

PNF stretching causes an important decrease in musculotendinous stiffness, which may possibly be associated with the inhibitory mechanism of muscle contraction itself, generated by the reduction in the reflex activation of stretch-sensitive mechanoreceptors (muscle spindle), produced by the momentary activation of antagonist muscles during isometric contraction and the subsequent stretch stimulus in the agonist muscles [68]. The GTO, when stimulated, provokes a reflex muscle relaxation. The tension produced during the contraction stimulates the GTO, causing a reflex relaxation of the same muscle during subsequent passive stretching. If relaxation occurs in the muscle opposite the muscle that experiences increased tension, the result is called reciprocal inhibition. During passive stretching, reciprocal inhibition is achieved by the simultaneous contraction of the muscle opposite the muscle being stretched. Tension in the contracting muscle stimulates the GTO and causes simultaneous reflex relaxation in the opposite muscle [36].

Although we performed analyses on the effect of PNF stretching on upper and lower limb muscle endurance, relatively few studies in the literature verified the effects of these stretching exercises on this capacity [69, 72], which consequently limits the extrapolation of our findings. Furthermore, it should be considered that a study included in our qualitative analysis [43] demonstrated that PNF stretching produces a significant decrease in lower limb muscle endurance capacity. Regarding muscle strength, although no studies with this outcome met our inclusion criteria, a systematic review study found a negative impact of PNF on this component [10]. It should be considered, that the decline in performance occurred only in muscular endurance tests, but not in muscular strength.

For muscle power, two studies [65, 68] included in our qualitative analysis observed a significant decline in this component after PNF performance, when compared to dynamic stretching and the control condition. However, when analyzed through meta-analysis, no significant results were found. With regard to the chronic effects of PNF, our qualitative analysis showed an increase in lower limb muscle strength after 8 weeks of intervention [75], similar to what occurred with the chronic effects of static stretching. However, when analyzed quantitatively, no results were found in our primary analysis. In short, PNF seems to offer immediate effects that negatively impact muscle strength, power, and endurance performance, which may not occur in long-term interventions, although current evidence is limited regarding chronic effects.

4.1.4 Effects of ballistic stretching on muscle strength and power performance

Our primary analyses did not find any significant results in comparisons involving ballistic stretching, for both acute and chronic effects. The scarcity of studies referring to this type of stretching performed before immediate or long-term performance was a limiting factor to establish in-depth analyses on this theme. Only two studies included in this systematic review presented quantitative results of post-intervention results, which only allowed the performance of primary analyses on the acute effect on lower limb muscle power [5], and the chronic effect of this stretching on the muscle strength of ankle plantar flexors [46]. Analysis involving the effect of ballistic stretching on muscle endurance was not performed, as no studies that were eligible according to our criteria addressed the impact of this type of stretching on this physical capacity. In this sense, more studies in this area should be carried out to elucidate this issue, especially considering that this technique is widely used by coaches.

Some authors reported that acute ballistic stretching is harmful for lower limb muscle power activities compared to no intervention [70], however, a study by Gao et al. [63] and Bradley et al. [68] found no significant results for vertical jump performance. Furthermore, a study by Bacurau et al. [71], showed that acute static stretching was worse than ballistic stretching and control condition in the 1 RM leg press test. Thus, the effect of ballistic stretching on muscle strength, endurance, and power performance still seems uncertain. Further studies that take into account ballistic stretching as an intervention are necessary. In principle, according to our findings and until further studies are available, there is no restriction on the use of ballistic stretching preceding main training.

4.2 Quality of evidence

Of the 41 studies included in our systematic review, eight were from South America [4, 16, 43, 51, 54, 66, 69, 71], thirteen from North America [2, 5, 13, 39, 44, 45, 52, 56, 57, 65, 70, 72, 73], eight from Europe [46, 50, 53, 58, 60, 67, 68, 73], one from Africa [76], and ten from Asia [47, 48, 49, 55, 59, 61, 62, 63, 64, 75, 77]. This scope allows for possible generalizations regarding the applicability of evidence in other locations. The methodological quality of the studies was low (mean 3.9 on the PEDro scale) which should be taken into account when interpreting the results of our review. This result made it impossible to carry out a sensitivity analysis. None of the studies blinded the participants and professionals who performed the interventions, however, for studies involving physical exercise, in which the stimuli are perceptible, this blinding becomes very difficult. It is unlikely that this bias could have influenced measures of muscle strength, endurance, and power. However, only three studies blinded the evaluators [2, 5, 54] and another three [4, 46, 60] blinded the volunteers to the intervention groups, which is an important methodological bias in most studies of the present review. Finally, 10 studies [4, 13, 39, 53, 59, 63, 67, 68, 70, 74] did not report quantitative results before and after the intervention, with measures of precision and variability, making meta-analysis calculations unfeasible.

4.3 Potential biases in the review process

Our review only included RCTs, which decreases the risk of bias. However, most studies did not hide the distribution of volunteers in each group. For the majority of the studies, we had the mean and standard deviation post-intervention measures of muscle strength, power, or endurance. However, for some studies [65, 66], it was necessary to carry out the conversion of dispersion measure values, from standard error to standard deviation, to enable the insertion of data in the meta-analysis. In addition, four studies [63, 68, 70, 71] that intervened with ballistic stretching did not have measures that allowed the comparison in meta-analysis graphs. This, therefore, restricted discussions about the effects of ballistic stretching on measures of muscle strength, endurance, and power. Another aspect that must be considered is that our search did not extend to all existing databases. However, we performed searches in three primary databases (PubMed, Web of Science, and LILACS), three secondary databases (CENTRAL, Scopus, and Science Direct) and clinical trials registry databases (clinicaltrials.gov and apps.who.int/trialsearch), aiming to find unpublished studies. In addition, we carried out a thorough search of all the bibliographic references of the studies included in the review, in an attempt to find other RCTs. Finally, only one analysis allowed visual inspection in a funnel plot (Supplementary Fig 28), in which no large or evident asymmetry was observed, hampered by the number of studies in the analysis (15 studies).

5. Conclusion

5.1 Implications for practice

Our results suggest that: 1) acute static stretching should not be part of warm-up routines before activities involving muscle strength and power performance, especially if performed at a volume $\geqslant$ 60-s and at low intensity, respectively, and if performed less than 5 minutes prior to the activity; 2) long-term static stretching has the potential to help increase muscle strength, being indicated in this case; 3) acute static stretching is better than PNF before muscle endurance activities; 4) acute dynamic stretching contributes to improved performance before activities involving muscle power performance, if performed with a volume $<$ 90-s per muscle group; 5) long-term dynamic stretching has the potential to help increase muscle power and is therefore indicated; 6) acute dynamic stretching is better than acute static stretching for muscle power and may be a viable option to build warm-up programs; 7) acute PNF stretching should be avoided before performing muscle endurance activities. Other forms of stretching and application conditions do not seem to imply the performance of muscle strength, endurance, and power. Finally, although our study contributes to the definition of warm-up protocols using stretching exercises, the effects on muscle strength, endurance, and power performance are not yet fully understood.

5.2 Implications for research

Our subgroup analyses helped in understanding how different factors (dose-response [volume and intensity], warm-up and time of assessment) influence the effects of stretching performed before activities that require muscle strength, endurance, and power in young adults, which may contribute to the definition of future research protocols. However, the small number of RCTs per analysis, the high heterogeneity of intervention protocols, and the low methodological quality of most studies limited safer extrapolations of our findings. For future studies, greater methodological care is suggested, especially with regard to the confidentiality of allocation and blinding of evaluators, in addition to greater clarity in the presentation of precision and variability measures. Rigorous conduction and detailed reports of the intervention with stretching regarding intensity control, assessment time, frequency, and rhythm of movements, are also necessary. Furthermore, more long-term studies should be carried out, aiming to establish the chronic effects of stretching. These factors may help to better clarify the effects of stretching on muscle strength, endurance, and power performance in young adults.

Author contributions

CONCEPTION: Raphael Gonçalves de Oliveira and Laís Campos de Oliveira.PERFORMANCE OF WORK: Alex Lopes dos Reis, Amanda Yasmin Vieira de Souza and Antonio Stabelini Neto.INTERPRETATION OR ANALYSIS OF DATA: Alex Lopes dos Reis and Raphael Gonçalves de Oliveira.PREPARATION OF THE MANUSCRIPT: Alex Lopes dos Reis, Amanda Yasmin Vieira de Souza and Antonio Stabelini Neto.REVISION FOR IMPORTANT INTELLECTUAL CONTENT: Antonio Stabelini Neto, Raphael Gonçalves de Oliveira and Laís Campos de Oliveira.SUPERVISION: Raphael Gonçalves de Oliveira and Laís Campos de Oliveira.

Ethical considerations

This study, as a systematic review and meta-analysis, is exempt from Institutional Review Board approval.

Funding

Universidade Estadual do Norte do Paraná – UENP/PROPG/EDITORA UENP.

Footnotes

Acknowledgments

We thank the Universidade Estadual do Norte do Paraná – UENP/PROPG/EDITORA UENP, for the partial financial support for this manuscript.

Conflict of interest

The authors have no conflicts of interest to report.

References

Page

. Current concepts in muscle stretching for exercise and rehabilitation. Int J Sports Phys Ther. 2012; 7(1): 109-119.

Curry

Chengkalath

Crouch

Romance

Manns

. Acute effects of dynamic stretching, static stretching, and light aerobic activity on muscular performance in women. J Strength Cond Res. 2009; 23: 1811-19.

Amiri-Khorasani

Kellis

. Static vs. dynamic acute stretching effect on quadriceps muscle activity during soccer instep kicking. J Hum Kinet. 2013; 39: 37-47.

Barbosa

Dantas

GAF

Pinheiro

. Acute effects of stretching and/or warm-up on neuromuscular performance of volleyball athletes: a randomized cross-over clinical trial. Sport Sci Health. 2020; 16: 85-92.

Jaggers

Swank

Frost

Lee

. The acute effects of dynamic and ballistic stretching on vertical jump height, force, and power. J Strength Cond Res. 2008; 22: 1844-49.

Bandy

Irion

Briggler

. The effect of time and frequency of static stretching on flexibility of the hamstring muscles. Phys Ther. 1997; 77: 1090-96.

Alter

. Science of flexibility third ed. Champaign: Human Kinetics. 2004.

Power

Behm

Cahill

Carroll

Young

. An acute bout of static stretching: Effects on force and jumping performance. Med Sci Sports Exerc. 2004; 36: 1389-96.

Woods

Bishop

Jones

. Warm-up and stretching in the prevention of muscular injury. Sport Med. 2007; 37: 1089-99.

10.

Behm

Blazevich

Kay

McHugh

. Acute effects of muscle stretching on physical performance, range of motion, and injury incidence in healthy active individuals: a systematic review. Appl Physiol Nutr Metab. 2016; 41: 1-11.

11.

Lauersen

Bertelsen

Andersen

. The effectiveness of exercise interventions to prevent sports injuries: a systematic review and meta-analysis of randomised controlled trials. Br J Sports Med. 2014; 48(11): 871-877.

12.

Knudson

Bennett

Corn

Leick

Smith

. Acute effects of stretching are not evident in the kinematics of the vertical jump. J Strength Cond Res. 2001; 15: 98-101.

13.

Knudson

Noffal

Bahamonde

Bauer

Blackwell

. Stretching has no effect on tennis serve performance. J Strength Cond Res. 2004; 18: 654-56.

14.

Young

Elias

Power

. Effects of static stretching volume and intensity on plantar flexor explosive force production and range of motion. J Sports Med Phys Fitness. 2006; 46: 403-11.

15.

Behm

Chaouachi

. A review of the acute effects of static and dynamic stretching on performance. Eur J Appl Physiol. 2011; 111: 2633-51.

16.

Pinto

Wilhelm

Tricoli

Pinto

Blazevich

. Differential effects of 30- vs. 60-second static muscle stretching on vertical jump performance. J Strength Cond Res. 2014; 28: 3440-46.

17.

Bishop

. Warm up II. Sport Med. 2003; 33: 483-98.

18.

Ferguson

. ACSM’s guidelines for exercise testing and prescription 9th Ed. J Can Chiropr Assoc. 2014; 58: 328.

19.

Cè

Margonato

Casasco

Veicsteinas

. Effects of stretching on maximal anaerobic power: the roles of active and passive warm-ups. J Strength Cond Res. 2008; 22: 794-800.

20.

Peck

Chomko

Gaz

Farrell

. The effects of stretching on performance. 2014. Curr Sports Med Rep. 2014; 13: 179-85.

21.

Kay

Blazevich

. Effect of acute static stretch on maximal muscle performance: a systematic review. Med Sci Sports Exerc. 2012; 44: 154-64.

22.

Simic

Sarabon

Markovic

. Does pre-exercise static stretching inhibit maximal muscular performance? A meta-analytical review. Scand J Med Sci Spor. 2013; 23: 131-48.

23.

Konrad

Moc̆nik

Titze

Nakamura

Tilp

. The influence of stretching the hip flexor muscles on performance parameters. A systematic review with meta-analysis. 2021. Int J Environ Res Public Health. 2021; 18: 1936.

24.

Uman

. Systematic reviews and meta-analyses. J Can Acad Child Adolesc Psychiatry. 2011; 20: 57-9.

25.

Mancini

Cardoso

Sampaio

Costa

LCM

Cabral

CMN

Costa

LOP

. Tutorial for writing systematic reviews for Brazilian Journal of Physical Therapy (BJPT). Braz J Phys Ther. 2014; 18: 471-480.

26.

Page

McKenzie

Bossuyt

Boutron

Hoffmann

Mulrow

Shamseer

Tetzlaff

Akl

Brennan

Chou

Glanville

Grimshaw

Hróbjartsson

Lalu

Loder

Mayo-Wilson

McDonald

McGuinness

Stewart

Thomas

Tricco

Welch

Whiting

Moher

. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ. 2021; 372: n71.

27.

Centre for Evidence-Based Medicine. Oxford. Available from: http://wwwcebm.net.36. 2012.

28.

Maher

Sherrington

Herbert

Moseley

Elkins

. Reliability of the PEDro scale for rating quality of randomized controlled trials. Phys Ther. 2003; 83: 713-21.

29.

Maher

Moseley

Sherrington

Elkins

Herbert

. A description of the trials, reviews and practice guidelines indexed in the PEDro database. Phys Ther. 2008; 88: 1068-77.

30.

Jadad

Moore

Carroll

Jenkinson

Reynolds

Gavaghan

McQuay

. Assessing the quality of reports of randomized clinical trials: is blinding necessary? Control Clin Trials. 1996; 17: 1-12.

31.

Verhagen

de Vet

de Bie

Kessels

Boers

Bouter

Knipschild

. The Delphi list: a criteria list for quality assessment of randomized clinical trials for conducting systematic reviews developed by Delphi consensus. J Clin Epidemiol. 1998; 51: 1235-41.

32.

Alter

. Science of flexibility. Human Kinetics Publishers, Champaign. 1996.

33.

Unick

Kieffer

Cheesman

Feeney

. The acute effects of static and ballistic stretching on vertical jump performance in trained women. J Strength Cond Res. 2005; 19: 206-12.

34.

Young

. The use of static stretching in warm-up for training and competition. Int J Sports Physiol Perf. 2007; 2: 212-16.

35.

Fletcher

Jones

. The effect of different warm-up stretch protocols on 20 meter sprint performance in trained rugby union players. J Strength Cond Res. 2004; 18: 885-88.

36.

Holcomb

. Improved stretching with proprioceptive neuromuscular facilitation. J Strength Cond Res. 2000; 22: 59-61.

37.

Sady

Wortman

Blanke

. Flexibility training: ballistic, static or proprioceptive neuromuscular facilitation? Arch Phys Med Rehabil. 1982; 63: 261-63.

38.

Hedrick

. Dynamic Flexbility Training. Strength Cond J. 2000; 22: 33-38.

39.

Behm

Kibele

. Effects of differing intensities of static stretching on jump performance. Eur J Appl Physiol. 2007; 101: 587-594.

40.

Corbin

Pangrazi

Franks

. Definitions: Health, fitness, and physical activity. Pres Counc Phys Fit Sports Res Dig. 2000; 3(9): 1-9.

41.

Higgins

JPT

Green

. Cochrane Collaboration. Cochrane handbook for systematic reviews of interventions. Chichester, England; Hoboken, NJ: Wiley-Blackwell. 2008.

42.

Cohen

. Statistical power analysis for the behavioural sciences. L. Erbraum Associates, Hillside, N.J., USA. 1988.

43.

Novaes

Sá

Rodrigues Neto

Araujo

Costa e Silva

Gomes

. The acute effects of stretching method and exercise order on the maximal number of repetitions in a strength training session. Med Sport. 2015; 68: 1-11.

44.

Brandenburg

. Duration of stretch does not influence the degree of force loss following static stretching. J Sports Med Phys Fitness. 2006; 46: 526-34.

45.

Winke

Jones

Berger

Yates

. Moderate static stretching and torque production of the knee flexors. J Strength Cond Res. 2010; 24: 706-10.

46.

Konrad

Tilp

. Effects of ballistic stretching training on the properties of human muscle and tendon structures. Journal Applied Physiology. 2014; 117: 29-35.

47.

Ikeda

Ryushi

. Effects of 6-Week static stretching of knee extensors on flexibility, muscle strength, jump performance, and muscle endurance. J Força Cond Res. 2021; 35: 715-23.

48.

Yamaguchi

Ishii

Yamanaka

Yasuda

. Acute effect of static stretching on power output during concentric dynamic constant external resistance leg extension. J Strength Cond Res. 2006; 20: 804-10.

49.

Yamaguchi

Ishii,

Yamanaka

Yasuda

. Acute effects of dynamic stretching exercise on power output during concentric dynamic constant external resistance leg extension. J Strength Cond Res. 2007; 21: 1238-44.

50.

La Torre

Castagna

Gervasoni

Cè

Rampichini

Ferrarin

Merati

. Acute effects of static stretching on squat jump performance at different knee starting angles. J Strength Cond Res. 2010; 24: 687-94.

51.

De Souza

LML

Paz

Eloi

Dias

Maia

Miranda

Lima

. Vertical jump performance after passive staticstretching of knee flexors muscles. Apunts Med Esport. 2016; 51: 131-36.

52.

Vetter

. Effects of six warm-up protocols on Sprint and jump performance. J Strength Cond Res. 2007; 21: 819-23.

53.

Walsh

. Effect of static and dynamic muscle stretching as part of warm up procedures on knee joint proprioception and strength. Hum Mov Sci. 2017; 55: 189-195.

54.

Solon Júnior

LJF

da Silva Neto

. Efeito do alongamento estático e da corrida submáxima no desempenho do salto contramovimento e sprint em jogadores universitários de voleibol. Retos. 2021; 39: 325-29.

55.

Yildiz

Gelen

Çilli

Karaca

Kayihan

Ozkan

Sayaca

. Acute effects of static stretching and massage on flexibility and jumping performance. J Musculoskeletal & Neuronal Interactions. 2020; 20: 498-504.

56.

Beedle

Rytter

Healy

Ward

. Pretesting static and dynamic stretching does not affect maximal strength. J Strength Cond Res. 2008; 22: 1838-43.

57.

Aguilar

DiStefano

Brown

. A dynamic warm-up model increases quadriceps strength and hamstring flexibility. J Strength Cond Res. 2012; 26: 1130-41.

58.

Fortier

Lattier

Babault

. Acute effects of short-duration isolated static stretching or combined with dynamic exercises on strength, jump and sprint performance. Science & Sports. 2013; 28: 111-7.

59.

Yang

Liu

Shiang

. Warm-up effects from concomitant use of vibration and static stretching after cycling. J Sport Med Phys Fit. 2017; 57: 362-68.

60.

Krc̆már

Xaverová

Lehnert

Krc̆márová

Šimonek

Kanásová

Bognar

Vanderka

Ruiz-Pérez

Ayala

. Acute effects of different durations of static stretching on the eccentric strength and power of leg flexor muscles. Isokinet Exerc Sci. 2018; 26: 43-52.

61.

Harmanci

Karavelioglu

. Effects of different warm-up methods on repeated sprint performance. J Biomed Res. 2017; 28: 7540-45.

62.

Alp

Çatıkkaş

Kurt

. Acute effects of static and dynamic stretching exercises on lower extremity isokinetic strength in taekwondo athletes. Isokinet Exerc Sci. 2018; 26: 307-11.

63.

Gao

Song

Zhang

. Acute effects of different stretching techniques on lower limb kinematics, kinetics and muscle activities during vertical jump. J Biomim Biomater Tissue Eng. 2019; 40: 1-15.

64.

Yamaguchi

Ishii

. Effects of static stretching for 30 seconds and dynamic stretching on leg extension power. J Strength Cond Res. 2005; 19: 677-83.

65.

Manoel

Harris-Love

Danoff

Miller

. Acute effects of static, dynamic, and proprioceptive neuromuscular facilitation stretching on muscle power in women. J Strength Cond Res. 2008; 22: 1528-34.

66.

Rodrigues

Hernandez

de Macedo Salgueirosa

Novack

Wassmansdorf

Wharton

Osiecki

. The influence of two static stretching protocols with different intensities on concentric knee extension strength. Isokinet Exerc Sci. 2017; 25: 41-6.

67.

Papadopoulos

Siatras

Kellis

. The effect of static and dynamic stretching exercises on the maximal isokinetic strength of the knee extensors and flexors. Isokinet Exerc Sci. 2005; 13: 285-91.

68.

Bradley

Olsen

Portas

. The effect of static ballistic, and proprioceptive neuromuscular facilitation stretching on vertical jump performance. J Strength Cond Res. 2007; 21: 223-26.

69.

Franco

Signorelli

Trajano

de Oliveira

. Acute effects of different stretching exercises on muscular endurance. J Strength Cond Res. 2008; 22: 1832-37.

70.

Samuel

Holcomb

Guadagnoli

Rubley

Wallmann

. Acute effects of static and ballistic stretching on measures of strength and power. J Strength Cond Res. 2008; 22: 1422-28.

71.

Bacurau

RFP

Monteiro

Ugrinowitsch

Tricoli

Cabral

Aoki

. Acute effect of a ballistic and a static stretching exercise bout on flexibility and maximal strength. J Strength Cond Res. 2009; 23: 304-08.

72.

Gomes

Simão

Marques

Costa

da Silva Novaes

. Acute effects of two different stretching methods on local muscular endurance performance. J Strength Cond Res. 2011; 25: 745-52.

73.

Morrin

Redding

. Acute effects of warm-up stretch protocols on balance, vertical jump height, and range of motion in dancers. J Dance Med Sci. 2013; 17: 34-40.

74.

Smith

Pridgeon

Hall

. Acute effect of foam rolling and dynamic stretching on flexibility and jump height. J Strength Cond Res. 2018; 32: 2209-15.

75.

Chen

Lin

Tseng

. Effects of 8-week static stretch and PNF training on the angle-torque relationship. J Med Biol Eng. 2009; 29: 196-201.

76.

Turki-Belkhiria

Chaouachi

Turki

Chtourou

Chtara

Chamari

Amri

Behm

. Eight weeks of dynamic stretching during warm-ups improves jump power but not repeated or single sprint performance. Eur J Sport Sci. 2014; 14: 19-27.

77.

Nakao

Ikezoe

Nakamura

Umegaki

Fujita

Umehara

Kobayashi

Ibuki

Ichihashi

. Chronic effects of a static stretching program on hamstring strength. J Strength Cond Res. 2021; 35: 1924-29.

78.

Nakamura

Yoshida

Sato

Yahata

Murakami

Kasahara

Fukaya

Takeuchi

Nunes

Konrad

. Comparison between high- and low-intensity static stretching training program on active and passive properties of plantar flexors. Front Physiol. 2021; 12: 796497.

79.

Reiner

Gabriel

Sommer

Bernsteiner

Tilp

Konrad

. Effects of a high-volume 7-week pectoralis muscle stretching training on muscle function and muscle stiffness. Sports Med Open. 2023; 9(1): 40.

80.

McHugh

Cosgrave

. To stretch or not to stretch: the role of stretching in injury prevention and performance. Scand J Med Sci Spor. 2010; 20: 169-81.

81.

Lima

Ruas

Behm

Brown

. Efeitos agudos do alongamento na flexibilidade e no desempenho: uma revisão narrativa. J Sci Sport Exer. 2019; 1: 29-37.

82.

Shrier

. Does stretching improve performance? A systematic and critical review of the literature. Clin J Sport Med. 2004; 14: 267-73.

83.

Nunes

Schoenfeld

Nakamura

Ribeiro

Cunha

Cyrino

. Does stretch training induce muscle hypertrophy in humans? A review of the literature. Clin Physiol Funct Imaging. 2020; 40(3): 148-56.

84.

Freitas

Vaz

Bruno

, et al. Stretching effects: high-intensity and moderate-duration vs. low-intensity & long-duration. Int J Sports Med. 2016; 37: 239-44.

85.

Ryan

Beck

Herda

Hull

Hartman

Costa

Defreitas

Stout

Cramer

. The time course of musculotendinous stiffness responses following different durations of passive stretching. J Orthop Sports Phys Ther. 2008; 38: 632-39.

86.

Kokkonen

Nelson

Eldredge

Winchester

. Chronic static stretching improves exercise performance. Med Sci Sports Exerc. 2007; 39: 1825-31.

87.

Rubini

Costa

Gomes

. The effects of stretching on strength performance. Sports Med. 2007; 37: 213-24.

88.

Nelson

Kokkonen

Winchester

Kalani

Peterson

Kenly

Arnall

. A 10-week stretching program increases strength in the contralateral muscle. J Strength Cond Res. 2012; 26: 832-36.

89.

Hough

Ross

Howatson

. Effects of dynamic and static stretching on vertical jump performance and electromyographic activity. J Strength Cond Res. 2009; 23: 507-12.

90.

Torres

Kraemer

Vingren

, et al. Effects of stretching on upperbody muscular performance. J Strength Cond Res. 2008; 22: 1279-85.

91.

McNair

Stanley

. Effect of passive stretching and jogging on the series elastic muscle stiffness and range of motion of the ankle joint. Br J Sports Med. 1996; 30: 313-17.

92.

Robbins

. Postactivation potentiation and its practical applicability: A brief review. J Strength Cond Res. 2005; 19: 453.

93.

McGowan

Pyne

Thompson

Rattray

. Warm-up strategies for sport and exercise: Mechanisms and applications. Sports Med. 2015; 45: 1523-46.

94.

Pearce

Kidgell

Zois

Carlson

. Effects of secondary warm up following stretching. Eur J Appl Physiol. 2009; 105: 175-83.

95.

Fletcher

. The effect of different dynamic stretch velocities on jump performance. Eur J Appl Physiol. 2010; 109: 491-98.

96.

Marek,

Cramer

Fincher

, et al. Acute effects of static and proprioceptive neuromuscular facilitation stretching on muscle strength and power output. J Athl Train. 2005; 40: 94.

97.

Miyahara

Naito

Ogura

Katamoto

Aoki

. Effects of proprioceptive neuromuscular facilitation stretching and static stretching on maximal voluntary contraction. J Strength Cond Res. 2013; 27: 195-201.

98.

Avela

Kyröläinen

Komi

. Altered reflex sensitivity after repeated and prolonged passive muscle stretching. J Appl Physiol. 1999.

Effects of stretching on muscle strength,endurance,and power performance: A systematic review and meta-analysis

Abstract

BACKGROUND:

OBJECTIVE:

METHODS:

RESULTS:

CONCLUSIONS:

Keywords

1. Introduction

2. Methods

2.1 Databases and search strategy

2.2 Selection of studies

2.3 Data extraction

2.4 Assessment of the methodological quality of studies

2.5 Definitions

2.5.1 Static stretching

2.5.2 Dynamic stretching

2.5.3 Proprioceptive neuromuscular facilitation

2.5.4 Ballistic stretching

2.5.5 Strength, power and muscular endurance

2.6 Synthesis of results

3. Results

3.1 Qualitative synthesis of studies

Table 1 Methodological quality of the studies included in the systematic review

3.3.1 Primary analysis: Acute effects of stretching

Table 2 Primary analysis: acute effects of stretching on muscle strength, power and endurance

Table 3 Primary analysis: chronic effects of stretching on muscle strength, power and endurance

Table 4 Subgroups analysis: acute effects of static stretching vs. control on muscle strength, power

4.1 Agreements and disagreements with other studies

4.1.1 Effects of static stretching on muscle strength, endurance, and power performance

Table 5 Subgroups analysis: acute effects of dynamic stretching vs. control on muscle strength, power

4.1.3 Effects of PNF on the performance of muscle strength, endurance, and power

4.1.4 Effects of ballistic stretching on muscle strength and power performance

4.2 Quality of evidence

4.3 Potential biases in the review process

5. Conclusion

5.1 Implications for practice

5.2 Implications for research

Author contributions

Ethical considerations

Funding

Footnotes

Acknowledgments

Conflict of interest

References

Table 1
Methodological quality of the studies included in the systematic review

Table 2
Primary analysis: acute effects of stretching on muscle strength, power and endurance

Table 3
Primary analysis: chronic effects of stretching on muscle strength, power and endurance

Table 4
Subgroups analysis: acute effects of static stretching vs. control on muscle strength, power

Table 5
Subgroups analysis: acute effects of dynamic stretching vs. control on muscle strength, power