Does a ten-week activate GAA warm-up intervention improve outcomes in adult male hurlers?

Abstract

BACKGROUND:

Injuries are frequent in hurlers and injury prevention exercise programmes implemented during their warm-up could play a role in reducing injury risk.

OBJECTIVES:

To determine whether a ten-week Activate GAA warm-up intervention improves outcomes (landing mechanics, dynamic postural control, quality of movement and hamstring and adductor strength) in hurlers.

METHODS:

A non-randomized controlled trial was implemented in adult male non-elite hurlers (intervention n=58; control n=59) and players were eligible if they were uninjured and currently playing with a non-elite hurling team. The landing error scoring system (LESS), Y balance test, overhead squat, single leg squat, hamstring strength test and adductor break test were assessed by one Certified Athletic Therapist pre- and post-intervention. The intervention group completed the Activate GAA warm-up prior to all training and games. Two participants were unable to complete post-testing due to injury in the control group only.

RESULTS:

The ANCOVA analysis revealed that the intervention group’s landing mechanics (LESS total score: p<0.0001, η_p²=0.34), postural control (Y balance test composite score: p<0.0001, η_p²=0.23), and quality of movement (Overhead squat: p<0.0001, η_p²=0.21; single leg squat dominant: p=0.04, η_p²=0.0.04; single leg squat non-dominant: p<0.0001, η_p²=0.12) were significantly better than the control group. Adductor and hamstring strength were not significantly improved (p>0.05).

CONCLUSIONS:

These findings support the use of the Activate GAA warm-up in non-elite adult male hurlers with improvements observed in landing mechanics, dynamic postural control and quality of movement. Randomised controlled trials to examine its effect on injury incidence along with consideration of long-term compliance are required.

Keywords

Injury prevention injury prevention exercise program hurlers GAA

1 Introduction

Hurling is a popular Irish national field-sport that is expanding internationally and is similar to shinty, lacrosse and field hockey [1 –3]. It is a high-intensity, contact, multi-directional sport, with players required to run, sprint, jump and frequently change direction at a high pace [1]. Sport specific skills are in high demand in this sport, with catching, striking, blocking, hooking, shouldering, lifting the ball from the ground with the hurley, soloing and hand passing the sliotar required frequently [1 , 4]. Hurling is a community sport played both at an elite (inter-county) and non-elite (club) level.

Injuries are frequent in hurling, with more match than training injuries in elite adult (61.11 vs 2.99 injuries per 1,000 hours) [1] and non-elite adolescent hurlers (11.11 vs 3.01 injuries per 1,000 hours) [3]. Injuries of the thigh (22.9%), pelvic/groin region (10-10.3%), knee (11.9–20%) and ankle (9.3–10%) are the most prevalent injuries [1, 3]. Most injuries are non-contact in nature occurring during sprinting, landing, jumping, catching and kicking [1, 3]. Therefore, the development of injury prevention programmes should focus on identifying and addressing risk factors for these injuries and subsequently evaluate the effectiveness of implementation strategies[5, 6].

Table 1
The Activate GAA warm-up exercises

Phase 1 Running, cutting and landing mechanics Phase 2 Strength, plyometrics and balance Phase 3

Circuit 1 Circuit 2 Agility and power

Jog* Arabesque^∧ Arabesque^∧ Three quarter pace run^∧

Skip Front leg swings Lateral leg swings High skip

Half pace run* Partner push into lunge (straight)^∧ Partner push into lunge (multi-directional)^∧ 2 forwards 1 back

Ice Hockey stop Nordic hamstring curl* Nordic hamstring curl* Bounds*

Jump, catch and land Front plank* Front plank with leg lift Fast plant and cut with ball^∧

Pick ups^∧ Side plank with leg lift (bent knee)^∧ Side plank with leg lift (straight leg) One on one

Partner shuffle Split leg squats Scissor jumps Fast feet shuffle (front to back, two legs)

Lunge stops Lateral hop and hold Diagonal hop and hold Fast feet shuffle (right to left, single leg)

Slow plant and cut Prisoner squats^∧ Prisoner squats^∧ Dynamic lunge

Squat stops Counter movement jump* Counter movement jump with a twist

Phase 1 Running, cutting and landing mechanics	Phase 2 Strength, plyometrics and balance	Phase 3
Jog*	Arabesque^∧	Arabesque^∧	Three quarter pace run^∧
Skip	Front leg swings	Lateral leg swings	High skip
Half pace run*	Partner push into lunge (straight)^∧	Partner push into lunge (multi-directional)^∧	2 forwards 1 back
Ice Hockey stop	Nordic hamstring curl*	Nordic hamstring curl*	Bounds*
Jump, catch and land	Front plank*	Front plank with leg lift	Fast plant and cut with ball^∧
Pick ups^∧	Side plank with leg lift (bent knee)^∧	Side plank with leg lift (straight leg)	One on one
Partner shuffle	Split leg squats	Scissor jumps	Fast feet shuffle (front to back, two legs)
Lunge stops	Lateral hop and hold	Diagonal hop and hold	Fast feet shuffle (right to left, single leg)
Slow plant and cut	Prisoner squats^∧	Prisoner squats^∧	Dynamic lunge
Squat stops	Counter movement jump*	Counter movement jump with a twist

*;Indicates exercise common with the GAA15 injury prevention warm-up. ^∧;Indicates an exercise that is similar to one included in the GAA15 injury prevention warm-up.

Deficits in landing mechanics, dynamic postural control, quality of movement and muscle strength have been proposed as risk factors for knee [7], ankle [8], lower extremity injuries [9] and hamstring [10] and pelvis/groin [11]. Injury prevention exercise warm-ups designed to address these factors have reduced injury risk across many sports [12 –16]. Two injury prevention exercise warm-ups have been developed for use in hurling, the GAA15 [17] and the Activate GAA warm-up [18]. The GAA15 is a modification of the FIFA11+ programme specific for Gaelic games. It has been found to reduce injury incidence [13] in collegiate Gaelic footballers and hurlers and lower extremity injury incidence in adolescent hurlers [19]. This reduction may be due to the observed improvements in dynamic postural control [19, 20] and landing technique [20] following a GAA15 programme. However, just 2 out of 26 coaches investigated utilised the GAA15, despite 96% believing that injury prevention exercise programmes could reduce injuries [21]. Recently, lower levels of player enjoyment and engagement and insufficient links to football-related goals have been identified as barriers to implementation of the FIFA11+ [22]. The Activate GAA warm-up is based on the FIFA11+, developed by Sports Institute Northern Ireland and Ulster GAA, and is similar to the GAA15. However, it is a high intensity warm-up with a greater focus on the inclusion of game specific skills and drills [18]. It has been formally adopted and rolled out nationally by the Camogie Association for Camogie players (the female equivalent of hurling) [23]. The Activate GAA warm-up consists of 29 exercises that are divided into three phases (Table 1) [18]. Phase one includes 10 exercises that focus on running, cutting and landing mechanics. Phase two is composed of 10 exercises to improve players’ strength, plyometrics and balance that alternate between two circuits on a monthly basis. There are nine exercises in phase three that focus on agility and power. Phase one and three are drill based and are completed prior to all training sessions and games whereas phase two is only conducted prior to training. The Activate GAA warm-up includes elements of the sport throughout (for example one drill incorporates jab and/or roll lifts that are required during hurling) and players are encouraged to hold their hurley during the warm-up for all tasks if possible.

To the authors’ knowledge no published research to date has examined the effectiveness of the Activate GAA warm-up. This study aimed to examine whether the implementation of a ten-week Activate GAA warm-up improves landing mechanics, dynamic postural control, quality of movement and hamstring and adductor strength in adult male non-elite hurlers.

2 Methods

2.1 Design and participants

A non-randomized controlled trial study design was implemented. A sample size calculation revealed 55 participants per group was needed to achieve a 95% statistical power at an alpha level of 0.05 using previous data from Root et al. [24]. Convenience sampling was used to recruit four adult male hurling teams from three clubs. One club was assigned the control group (two teams, n=59) and two clubs the intervention (two teams, n=58). This was not randomly assigned and the tester was not blinded to the intervention or control group clubs. Players were eligible for inclusion if they were a current adult hurling player for the recruited club and were currently uninjured. Ethical approval was granted by Dublin City University’s Research Ethics Committee (DCUREC/2017/152) and informed consent was gained.

2.2 Procedures

Testing and the intervention took place in 2017-2018. Players underwent a battery of 6 tests (Fig. 1) during their pre-season conducted by one Certified Athletic Therapist which took approximately 25 minutes per participant. Figure 1 displays the order of tests that was completed for all participants. Rest periods between tests and reps were included to minimise risk of fatigue. Pre- and post-testing took place in the Dublin City University athletic therapy clinical laboratory or in the individual recruited club depending on participant convenience. Tests were chosen to examine landing mechanics (LESS), dynamic postural control (Y balance test), quality of movement (overhead squat and single leg squat) and muscle strength (adductor break test and hamstring isometric strength test). Excellent intra-tester reliability for all tests (ICC>0.90) was observed. The reliability testing took place one week apart at the same time and location.

Fig.1

Battery of tests and testing order.

Leg dominance was noted and defined as their preferred kicking leg [25]. The Y balance test was conducted on both legs. Participants stood with the distal end of their longest toe at the red line of the Y balance testing kit platform. Participants then pushed the reach indicator with their contralateral toe as far as they could in the anterior, posteromedial and posterolateral directions and the distance to the nearest centimetre was noted. Four practice trials were conducted [26], followed by three trials with the average score used for analysis. A trial was deemed invalid if the participant lost their balance in the stance leg and either moved off the platform or touched the ground with the contralateral leg, failed to maintain contact with the reach indicator throughout the movement, kicked the reach indicator, placed the foot on the top of the reach indicator to aid their balance or did not maintain their hands on their hips throughout the trial [27]. The reach distances were normalised according to leg length, which was measured from the anterior superior iliac spine to the medial malleolus [28]. The Landing Error Scoring System test was conducted according to O’Malley et al. [20] and is a valid and reliable test to examine jump landing techniques [29] and is associated with increased risk of sustaining an injury [30]. Half their body height was calculated and participants were required to jump forward from a 30 cm box to this distance and upon landing jump vertically as high as possible. When jumping vertically participants were instructed to lift their hands in the air like they are aiming to catch a ball as they would typically do in hurling. Two practice trials were completed, followed by three trials which were recorded and the last trial was scored. Video cameras (Canon Legria HF R706) were placed 2.5 m away from the box to capture the frontal and sagittal plane.

The overhead squat and single leg squat on both legs were conducted as outlined by O’Connor et al. [9]. For the overhead squat, participants were required to stand shoulder-width distance apart and with a dowel overhead, squat down as far as comfortable while keeping their heels on the floor. To complete the single leg squat, the participant stood on the leg to be tested at the edge of a step with their contralateral leg outstretched in front and their arms outstretched to 90 degrees, elbows straight and hands clasped together. Participants were instructed to squat down as far as was comfortable and return to the starting position. Three trials were completed for each test and the test was scored live. An overall rating was provided for each test (1=poor, 2=average, 3=excellent). Two strength tests were conducted on both legs using a hand held dynamometer (HHD) (Commander Echo JTECH Medical, Salt Lake City, Utah, USA). The adductor break test to measure eccentric adductor strength was completed according to Haroy et al. [31]. The participant lay side-lying with the leg to be tested in a straight position and the non-tested leg in 90 degrees of hip and knee flexion on a plinth. Participants stabilised themselves by holding onto the edge of plinth. The HHD was placed 5 cm proximal to the most prominent part of the medial malleolus, and a 3–5 second isometric maximal voluntary contraction was performed by the participant before the primary researcher performed a break contraction. The participant conducted 1 practice trial, then performed 3 maximal tests with 30 second rests between each test. The hamstring isometric strength test was completed according to Reurink et al. (2015) in the prone position with the tested leg at 90 degrees knee flexion. The HHD was placed on the participant’s heel and participants were instructed to gradually increase their strength over 3–5 seconds and perform an isometric maximal voluntary contraction before the primary researcher performed a break contraction. Participants completed 4 practice trials progressing their strength to 25%, 50%, 75% and 100% of their strength to familiarise themselves with the test. Three break tests were then conducted with a 60 second rest period between each test. The highest result for both strength tests werenoted.

The intervention ran for ten weeks and players in the control group underwent their typical warm-up routine. This was not a standardised warm-up and did not include a specific injury prevention programme and no advice was given by the researchers on what to include. The warm-ups generally consisted of, to start with, running drills of gradually increasing intensity, followed by sport specific hurling skill drills that gradually increased intensity followed by static stretching. The intervention group first undertook a practice session (30 minutes’ duration) to teach players the Activate GAA warm-up. Each exercise was outlined and demonstrated by the Certified Athletic Therapist prior to the players undertaking the exercise. Players were verbally informed of key coaching cues during each exercise and mistakes were corrected. Coaches were present at this session and were encouraged to assist the Certified Athletic Therapist in re-enforcing the coaching cues. The intervention group then underwent ten weeks of normal training and matches (Intervention team 1:16 trainings/8 games; Intervention team 2:18 trainings/7 games). The intervention was delivered at all sessions, however not all players attended all training/games, with 76% and 72% attendance reported for team 1 and team 2 respectively. Attendance was captured at each session by the Certified Athletic Therapist and coaching staff. The time taken to complete the intervention reduced over the course of the intervention (Training: 29 minutes to 16 minutes) however prior to games the intervention took on average 10.5 minutes. Following the ten weeks, all players repeated the pre-intervention battery of tests by the same Certified Athletic Therapist that completed the baseline testing. The tester was not blinded to the group the participant was in. No drop-outs were observed in the intervention group however 2 players were unable to complete post-testing due to injury (one hamstring and one adductor injury).

2.3 Data analysis

The quantitative data were entered into SPSS Version 26.0 (IBM Corp. 2019. Armonk, NY). The combined composite score for the Y balance test was calculated according to the following equation: $\begin{matrix} Composite score \\ = [\frac{Anterior + Posteromedial + Posterolateral}{Leg length X 3}] \\ \times 100 \end{matrix}$

Equation 1. Calculation of the composite score

A one-way ANCOVA was conducted to determine any statistically significant differences between group (intervention vs control) on the post-intervention outcome scores occurred while controlling for the corresponding pre-intervention outcome scores. The outcome variables are presented in Table 2 and their descriptive statistics were calculated and reported, along with the adjusted means utilised in the ANCOVA. Effect sizes were determined using partial eta squared (η_p²) and classified as small (0.01), moderate (0.06) or large (0.14) [33]. Strength asymmetry or asymmetry index was calculated according to Bini and Hume [34] using the following calculation: (Dominant leg –Non dominant leg)/(Dominant leg + Non dominant leg/2)*100. Statistical significance was set at p<0.05.

Table 2
Outcome variables included in the ANCOVA analysis

Y balance test Composite score

Anterior normalised score

Posteromedial normalised score

Posterolateral normalised score

Less overall score

Overhead squat overall impression score

Single leg squat Dominant

Non-dominant

Adductor break test Dominant

Non-dominant

Asymmetry

Hamstring strength score Dominant

Non-dominant

Asymmetry

Y balance test	Composite score
	Anterior normalised score
	Posteromedial normalised score
	Posterolateral normalised score
Less overall score
Overhead squat overall impression score
Single leg squat	Dominant
	Non-dominant
Adductor break test	Dominant
	Non-dominant
	Asymmetry
Hamstring strength score	Dominant
	Non-dominant
	Asymmetry

3 Results

The one-way ANCOVA analysis results are presented in Table 3. After controlling for the pre-intervention outcome scores, the intervention group performed significantly better with a large effect size for the Y balance test composite score, (p<0.0001, η_p²=0.23), LESS total score (p<0.0001, η_p²=0.34) and overhead squat (p<0.0001, η_p²=0.21). In fact, the intervention group mean error score in the LESS improved from a poor score (6.4±2.7, value>6) to a good score (4.5±2.4, value of 4–5) by the end of the intervention. The intervention group also preformed significantly better post-intervention in the single leg squat on the non-dominant (p=0.04, η_p²=0.04) and dominant (p<0.0001, η_p²=0.12) leg with a small and moderate effect size respectively. No significant difference was observed for hamstring or adductor strength (p>0.05).

Table 3
Pre and post-intervention and control mean values, percentage change and differences between the intervention and control group while controlling for baseline scores and the adjusted means (n=115)

Test Score Intervention Control ANCOVA

Pre Mean±SD Post Mean±SD % Adj Mean Pre Mean±SD Post Mean±SD % Adj Mean p η _p ²

Y balance test Dom Ant% (LL) 70.8±6.8 74.6±7.7 5.4 77.0 75.5±7.6 75.9±8.3 0.5 73.5 <0.0001* 0.19

Dom PM% (LL) 110.1±7.6 112.7±10.8 2.4 114.8 114.0±9.2 114.7±10.1 0.6 112.6 0.04* 0.04

Dom PL% (LL) 108.2±7.7 111.7±8.5 3.2 116.4 117.6±9.5 117.6±9.9 0.0 112.9 <0.0001* 0.17

Non-dom Ant% (LL) 70.7±6.8 73.5±6.9 4.0 75.5 74.9±8.2 75.3±8.8 0.5 73.3 <0.0001* 0.11

Non-dom PM% (LL) 110.0±6.9 112.1±6.6 1.9 113.7 113.2±9.6 113.3±9.4 0.1 111.8 <0.0001* 0.40

Non-dom PL% (LL) 107.3±7.3 109.7±7.4 2.2 113.7 115.4±9.1 116.1±9.6 0.6 112.2 0.01* 0.06

Composite% (LL) 96.2±6.2 99.1±6.6 3.0 101.9 101.8±7.9 102.1±8.3 0.3 99.3 <0.0001* 0.23

LESS Total score 6.4±2.7 4.5±2.4 –29.7 3.8 4.7±2.5 4.9±2.5 4.3 5.6 <0.0001* 0.34

Overhead squat Total score 2.0±0.8 2.3±0.7 15.0 2.2 1.8±0.8 1.8±0.8 –21.7 1.9 <0.0001* 0.21

Single leg squat Dominant TS 2.0±0.8 2.1±0.8 5.0 2.0 1.8±0.8 1.8±0.9 0 1.9 0.04* 0.04

Non-dominant TS 1.9±0.8 2.2±0.8 15.8 2.1 1.8±0.8 1.7±0.8 –5.6 1.8 <0.0001* 0.12

Hamstring strength Dominant (N) 163.4±16.9 175.3±18.1 7.3 215.3 161.3±29.8 162.2±28.0 0.6 216.2 0.59 0.00

Non-dominant (N) 159.5±19.0 172.6±18.4 8.2 211.4 156.9±31.4 158.4±28.8 1.0 214.6 0.20 0.01

Asymmetry (N) 2.6±7.2 1.7±7.1 –34.6 1.9 3.1±9.0 2.5±9.8 –19.4 0.5 0.27 0.01

Adductor break test Dominant (N) 216.3±24.5 217.4±24.0 0.5 215.3 212.0±40.0 214.2±39.3 1.0 216.2 0.59 0.00

Non-dominant (N) 208.1±23.6 209.1±23.3 0.5 211.4 213.1±34.2 216.9±35.8 1.8 214.6 0.20 0.01

Asymmetry (N) 3.9±6.4 0.0±15.1 –100.0 1.9 3.9±6.5 –1.6±12.1 –141.0 0.5 0.27 0.01

Test	Score	Intervention	Control	ANCOVA
Y balance test	Dom Ant% (LL)	70.8±6.8	74.6±7.7	5.4	77.0	75.5±7.6	75.9±8.3	0.5	73.5	<0.0001*	0.19
	Dom PM% (LL)	110.1±7.6	112.7±10.8	2.4	114.8	114.0±9.2	114.7±10.1	0.6	112.6	0.04*	0.04
	Dom PL% (LL)	108.2±7.7	111.7±8.5	3.2	116.4	117.6±9.5	117.6±9.9	0.0	112.9	<0.0001*	0.17
	Non-dom Ant% (LL)	70.7±6.8	73.5±6.9	4.0	75.5	74.9±8.2	75.3±8.8	0.5	73.3	<0.0001*	0.11
	Non-dom PM% (LL)	110.0±6.9	112.1±6.6	1.9	113.7	113.2±9.6	113.3±9.4	0.1	111.8	<0.0001*	0.40
	Non-dom PL% (LL)	107.3±7.3	109.7±7.4	2.2	113.7	115.4±9.1	116.1±9.6	0.6	112.2	0.01*	0.06
	Composite% (LL)	96.2±6.2	99.1±6.6	3.0	101.9	101.8±7.9	102.1±8.3	0.3	99.3	<0.0001*	0.23
LESS	Total score	6.4±2.7	4.5±2.4	–29.7	3.8	4.7±2.5	4.9±2.5	4.3	5.6	<0.0001*	0.34
Overhead squat	Total score	2.0±0.8	2.3±0.7	15.0	2.2	1.8±0.8	1.8±0.8	–21.7	1.9	<0.0001*	0.21
Single leg squat	Dominant TS	2.0±0.8	2.1±0.8	5.0	2.0	1.8±0.8	1.8±0.9	0	1.9	0.04*	0.04
	Non-dominant TS	1.9±0.8	2.2±0.8	15.8	2.1	1.8±0.8	1.7±0.8	–5.6	1.8	<0.0001*	0.12
Hamstring strength	Dominant (N)	163.4±16.9	175.3±18.1	7.3	215.3	161.3±29.8	162.2±28.0	0.6	216.2	0.59	0.00
	Non-dominant (N)	159.5±19.0	172.6±18.4	8.2	211.4	156.9±31.4	158.4±28.8	1.0	214.6	0.20	0.01
	Asymmetry (N)	2.6±7.2	1.7±7.1	–34.6	1.9	3.1±9.0	2.5±9.8	–19.4	0.5	0.27	0.01
Adductor break test	Dominant (N)	216.3±24.5	217.4±24.0	0.5	215.3	212.0±40.0	214.2±39.3	1.0	216.2	0.59	0.00
	Non-dominant (N)	208.1±23.6	209.1±23.3	0.5	211.4	213.1±34.2	216.9±35.8	1.8	214.6	0.20	0.01
	Asymmetry (N)	3.9±6.4	0.0±15.1	–100.0	1.9	3.9±6.5	–1.6±12.1	–141.0	0.5	0.27	0.01

SD; Standard deviation,%; Percentage change, Adj; Adjusted mean in the ANCOVA, Pre; pre-intervention score, Post; post-intervention score, Ant; Anterior, PM; Posteriomedial, PL; Posteriolateral,% LL; Percentage Leg Length, mm; Millimetres, TS; Total score, N; newtons.

4 Discussion

This study aimed to examine the effectiveness of a ten-week Activate GAA warm-up intervention on ameliorating risk factors for prevalent injuries in hurling. The findings of this study support the use of the Activate GAA warm-up and observed improvements in landing mechanics, dynamic postural control and movement quality, but not adductor or hamstring strength. Therefore, similar to the GAA15 which also reported improvements in landing technique [20] and dynamic postural control [19, 20], this intervention ameliorates risk factors for injury in adult club level hurlers. This finding further demonstrates the effectiveness of an injury prevention warm-up, that a coach can feasibly deliver, in minimising injury risk in the community sport setting. Future research investigating its impact on reducing injury incidence is required.

Movement quality (overhead squat and single leg squat scores) and landing technique (LESS score) significantly improved following the ten-week intervention, indicating the Activate warm-up reduced lower extremity injury risk in hurlers. In fact, participants that completed the Activate warm-up improved their landing technique score from a “poor” (>6) to a “good” [4, 5] classification. Whereas the control group remained unchanged within the “good” classification. This is similar to previous research in a number of field based sports using group delivered, neuromuscular injury prevention programmes such as the GAA15 [20], the FIFA11+ [36], in physically active adults [37], and youth athletes [24] where an injury prevention programme significantly improved LESS scores. Given that the LESS correlates with 3d motion analysis [38] and higher scores are associated with sustaining an injury [30], this suggests that the Activate GAA warm-up may be useful in reducing lower limb injuries.

Poor dynamic postural control has also been demonstrated to increase lower extremity injury risk in sporting populations [39 –41] and the current intervention successfully improved dynamic postural control, as measured by the Y balance test in adult hurlers. This is similar to the effects seen following the GAA15 [20] but better than those observed following the FIFA11+ for the Y balance test [42] or the star excursion balance test [43]. Due to the frequency of lower extremity injuries and ankle injuries in hurling improving dynamic postural control may consequentially reduce lower extremity injury risk and is a welcome finding.

The Activate GAA warm-up did not result in a statistically significant higher hamstring strength score. However, improvements of 7.3 and 8.2% for dominant and non-dominant limbs respectively were noted which may be clinically significant. Although the effect of the GAA15 on hamstring strength has not been investigated, the magnitude of changes in isometric strength in the current study are similar to the 7.7% increases in eccentric strength following the FIFA11+ programme [31]. These improvements in the current study may be largely attributed to the inclusion of the Nordic hamstring exercise which increases hamstring strength [44] and can halve the number of hamstring strains sustained in athletes [45]. However, the Activate GAA warm-up recommends 5–10 reps per training session, with players in the current study undertaking an average weekly volume of 8–16 reps. A recent meta-analysis found that the lowest average weekly reps found to statistically improve eccentric strength was 21 reps [46]. Therefore, increasing the Nordic hamstring exercise reps to the recommended number of reps in the Activate GAA warm-up and similar injury prevention warm-ups would be beneficial. The current study did not find any effect on hamstring strength asymmetry which may be due to a number of factors. Firstly, between limb hamstring strength asymmetries are an inconsistent risk factor for injury [47, 48] with large asymmetries of more than 15% a potential risk factor [47]. These were much higher than the 1.7–3.1% asymmetries in the current study. Secondly, the Nordic hamstring exercise is a bilateral exercise which may allow the stronger limb to compensate for the weaker limb if feedback is not provided [49]. It has therefore been suggested that unilateral exercises may avoid this and have subsequently been recommended for hamstring strengthening exercises [50], particularly when large asymmetries are present.

A significant improvement in adductor strength compared to the control group was not observed. Although this risk factor has not been investigated following the GAA15, the finding of the current study are similar to those following the FIFA11+ [31]. This may not be surprising given that there is no exercise that primarily targets hip adductor strength in the activate programme or the original FIFA11+. This was addressed in the FIFA11+ programme by including the Copenhagen adduction exercise Therefore, the incorporation of an adductor focussed exercise such as the Copenhagen adduction exercise into the Activate GAA warm-up or other warm-ups for sports with a high incidence of adductor injuries is warranted to address this risk factor for pelvic/groin injuries.

A substantial time investment is required by coaches and players to implement the Activate GAA warm-up at the beginning. In the current study it took approximately a half an hour to at the start of the study as there is an important focus in this intervention on correcting mechanics and encouraging good technique. However, over the course of the ten weeks this time commitment was halved. The intervention took on average 10.5 minutes before matches, as phase 2 (strength, plyometrics and balance exercises) was removed. Therefore, coaches could potentially consider implementing phase 2 at the end of the training session. Previous research in soccer has found that re-scheduling part 2 of the FIFA11+ injury prevention programme led to a decreased amount of severe injuries, total injury burden and improved player compliance [51].

4.1 Limitations

Due to an error in the transfer of data, height, weight and age was lost and was unable to be reported in the current study. The authors were consequentially unable to normalise the strength measures by weight. The intervention was not randomly allocated and so selection bias may impact these findings. In addition, when conducting the battery of tests, the tester was not blinded to whether the participant was in the intervention or control group. Future randomised controlled trials should be conducted. Also, the majority of research investigating strength as a risk factor for hamstring strain injuries measure eccentric strength whereas we recorded isometric strength which may limit the applicability of our findings. This research was conducted in non-elite adult hurlers and so cannot be generalised to other hurling populations or female Camogie players. Therefore, the effectiveness of this intervention should also be established in adolescent and elite adult hurlers and female players.

5 Conclusions

This study found that the Activate GAA warm-up significantly improved a number of risk factors for injury including landing mechanics, postural control and movement quality and therefore, it can be recommended to reduce risk of injury. However, no improvements in adductor strength or statistically significant improvement in hamstring strength were observed. Therefore, the Activate GAA warm-up, supplemented by an additional adduction exercise and increased Nordic hamstring exercise volume, may be a useful injury prevention warm-up for adult hurlers. This study further highlights that a coach led injury prevention exercise programme, which incorporates sport specific elements and is delivered as part of a warm-up can ultimately minimise players’ injury risk. A randomized controlled trial to examine whether the Activate GAA warm-up effectively reduces injury incidence in hurlers is required. If proven effective, consideration of compliance to the programme is then required to establish its utility as an injury prevention programme for hurlers nationally.

Funding

No funding was provided for this study.

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