Are Moderate and Vigorous Leisure-Time Physical Activity Associated With Musculoskeletal Pain? A Cross-Sectional Study Among 981 Physical Therapists

Abstract

Purpose:

Musculoskeletal pain (MP) is common among workers, especially for health-care professionals. Paradoxically, many of those rehabilitating patients for pain—that is, physical therapists (PTs)—also have pain. Adequate levels of physical activity are recommended for cardiovascular and musculoskeletal health. However, the association between physical activity and MP among PTs remains unknown. This study aims to determine the association between moderate and vigorous leisure-time physical activity levels and MP in PTs.

Design:

Cross-sectional study.

Setting:

Workplace.

Participants:

Nine hundred eighty-one PTs.

Measures:

Data on MP and leisure-time physical activity were collected using an online survey.

Analysis:

The odds for having lower level of MP as a function of physical activity were estimated using binary logistic regression controlled for various confounders.

Results:

Performing ≥75 min/week of vigorous leisure-time physical activity increased the odds of experiencing lower levels of neck–shoulder pain (odds ratio = 1.43, 95% confidence interval, 1.05-1.94). No association was found neither between vigorous nor between moderate leisure-time physical activity and MP in the arm-hand or back.

Conclusion:

Performing ≥75 min/week of vigorous leisure-time physical activity is associated with lower levels of MP in neck and shoulders among PTs. No associations were found between vigorous or moderate leisure-time physical activity and MP in arm-hand and back.

Keywords

musculoskeletal disorders occupational health exercise workplace lifestyle

Purpose

Numerous studies have reported that health-care professionals have high risk of musculoskeletal pain (MP), due to the physically demanding nature of their tasks.^1,2 For instance, physical therapists (PTs), who are typical specialists for MP management, deal with different risk factors for having MP themselves. However, few studies have been focused on the modifiable factors associated with MP among this occupational group.

Lifestyle factors are considered an interesting target to promote health interventions. Among these, regular physical activity has shown to provide numerous health benefits, including the reduction in risk factors and the prevention of chronic health problems. In this regard, vigorous exercise is much more efficient than moderate exercise to increase physical capacity, for example, in terms of cardiorespiratory fitness.³ However, while interventions with vigorous levels of physical exercise have found positive results in terms of reduction in pain in chronic low back pain patients⁴ or among workers,^5,6 there are no studies evaluating the association between physical activity and MP among PTs.

This study aims to analyze the association between moderate and vigorous physical activity and MP in PTs. We hypothesized that higher levels of both vigorous and moderate physical activity would have a protective effect for MP, in comparison to those PTs less physically active.

Methods

Design

This cross-sectional study was conducted in 2017 as part of a larger research study investigating the working environment among PTs. An online questionnaire was sent to the registered PTs from different professional associations. Ethical approval was granted by the institution’s review board of the University of Valencia in accordance with the principles of the Declaration of Helsinki. All data of the study were treated anonymously.

Sample

Analyses are based on data from 981 PTs. Participants already retired or not actively working at the time of the investigation were excluded.

Measures

The questionnaire was designed to collect information about self-reported MP and moderate/vigorous physical activity during leisure time among PTs.

Self-reported level of leisure-time physical activity was reported according the Global Physical Activity Questionnaire.⁷ A categorical score of low, moderate, and vigorous leisure-time physical activity was allocated and recoded, resulting in a binary variable indicating moderate and vigorous leisure-time physical activity. Moderate physical activity was defined as “activities that require moderate physical effort and cause small increases in breathing or heart rate,” and vigorous physical activity referred to “activities that require hard physical effort and cause large increases in breathing or heart rate.” Each of these variables was categorized according to the sum of minutes recommended during a normal week (0, 0-149 minutes, or >150 minutes of moderate physical activity, or 0, 0-74, or >75 minutes of vigorous physical activity).⁸

To report the prevalence and pain intensity in neck–shoulder, arm–hand, and back during the last month, a modified Nordic Musculoskeletal Questionnaire⁹ was used. Using a simple body diagram, participants were asked to rate pain intensity using a 0 to 10 analogue scale, where 0 meant “no pain at all” and 10 was considered “pain is as bad as it could possibly be.”

Statistical Analysis

All statistical analyses were performed using the SAS statistical software for Windows (Proc Logistic, SAS version 9.4). Descriptive statistics were used to report demographic characteristics of the participants, including age, body mass index, gender, education, smoking, alcohol units per week, and pain intensity (≥3 on a scale of 0-10 in the back, neck/shoulders, and arm/hand). Using binary logistic regression, odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for having low MP (<3 on a scale of 0-10) in different body areas (dependent variables) in function of the total amount of vigorous leisure-time physical activity (0, 1-74, and ≥75 min/week) and moderate leisure-time physical activity (0, 1-149, and ≥150 min/week) as mutually adjusted independent variables (reference category: 0 min/week), after adjusting for confounding factors (gender, education, experience, working hours, setting, type of treatment, number of patients per week, and work position). As an exposure variable, total physical activity was evaluated by multiplying vigorous physical activity minutes by 2 and adding that value to the reported minutes of moderate physical activity.

Results

In all, 1006 PTs replied to the questionnaire. Twenty-five questionnaires were excluded because of missing data for at least one of the main variables of the study, obtaining a final sample size of 981 patients. Demographic data and pain intensity of the participants are summarized in Table 1.

Table 1.

Demographics, Lifestyle, and Pain.

	N	Mean	SD	%
Gender
Men	288			29.4
Women	693			70.6
Education
Bachelor (3-year)	479			48.8
Bachelor (4-year)	236			24.1
Master	258			26.3
PhD	8			0.8
Smoking
No	852			86.9
Yes	129			13.2
Age, years	981	34.3	8.0
BMI, kg/m²	981	23.3	3.4
Alcohol, units per week	981	2.2	2.3
Pain intensity (0-10 mean SD and % ≥3)
Neck–shoulder	981	2.6	2.2	43.4
Arm–hand	981	1.5	1.9	23.9
Back	980	2.5	2.2	42.1

Abbreviations: SD, standard deviation; BMI, body mass index.

The odds for experiencing lower levels of pain in neck–shoulder were higher in those PTs performing ≥75 min/week of vigorous leisure-time physical activity, with 0 min/week of vigorous physical activity as a reference (OR = 1.43, 95% CI, 1.05-1.94; Table 2). However, the analysis did not reveal any significant difference between vigorous leisure-time physical activity and pain in the arm–hand (OR = 0.84, 95% CI, 0.59-1.19) or back (OR = 1.20, 95% CI, 0.89-1.63). The odds for having lower levels of pain were not significantly lower in those PTs performing moderate leisure-time physical activity. Additionally, a positive significant association was found with having MP in the neck–shoulders in those PTs who performed <150 min/week of total physical activity (OR = 1.58, 95% CI: 0.98-2.54). However, no associations were found with MP in the arm–hand (OR = 1.38, 95% CI: 0.79-2.42) or in the back (OR = 1.12, 95% CI: 0.70-1.79).

Table 2.

Odds Ratios (95% Confidence Intervals) for Having a Low Level of Musculoskeletal Pain (<3 on a Scale of 0-10) in the Neck–Shoulder, Arm–Hand, and Back From Different Durations of Moderate and Vigorous Physical Activity During Leisure.

				Neck–Shoulder Pain	Arm–Hand Pain	Back Pain
	Min/Week	N	%	OR (95% CI)	OR (95% CI)	OR (95% CI)
Moderate physical activity	0	256	25.5	1	1	1
	1-149	360	35.8	1.15 (0.80-1.66)	1.17 (0.77-1.76)	1.13 (0.79-1.62)
	150 or more	389	38.7	0.80 (0.56-1.15)	1.07 (0.72-1.61)	0.98 (0.69-1.39)
Vigorous physical activity	0	409	40.7	1	1	1
	1-74	104	10.4	0.92 (0.57-1.48)	0.71 (0.41-1.21)	0.72 (0.45-1.15)
	75 or more	492	49.0	1.43 (1.05-1.94)	0.84 (0.59-1.19)	1.20 (0.89-1.63)

Abbreviations: CI, confidence interval; OR, odds ratio.

Bold values denote a statistically significant result (p < 0.05).

Discussion

Summary

The main findings of the present study are that ≥75 min/week of leisure-time vigorous physical activity are associated with lower levels of MP in the neck–shoulders among PTs. However, a similar intensity seems to not confer the same benefit in the back or in the arm–hand. Moderate leisure-time physical activity did not show any significant association with MP, partially confirming our hypothesis.

According to the current physical activity guidelines for health, adults should do at least 150 min/week of moderate physical activity, or 75 min/week of vigorous intensity physical activity, or an equivalent combination of both.¹⁰ Contrariwise, over 25% of those surveyed reported not to perform any moderate physical activity, and almost 40% reported not to do any vigorous physical activity during leisure time. These rates might alert us that physical activity does not receive enough attention among PTs.

Thereby, the association found between vigorous physical activity and MP would suggest that increasing the total amount of vigorous leisure-time physical activity might be effective in preventing and/or reducing neck–shoulder pain among PTs. One possible explanation for this finding might be that by increasing the physical capacity of the worker, the relative workload might be reduced. Furthermore, physical exercise may improve the oxygenation of distant tissues of the body, by increasing the blood flow in both working and nonworking muscles,^11,12 due to an improved endothelium-dependent vasodilation.¹³ However, the intensity should be high enough to improve the oxygenation of these tissues, being moderate physical activity not enough intense to produce this effect. Regardless, the analysis revealed that those respondents who did not meet the current physical activity guidelines (including the combination of the total amount of vigorous and moderate physical activity) had higher odds for having MP in the neck–shoulders. Thus, it could be that for preventing or reducing MP in this body area, a minimum amount of total physical activity might be required. However, further longitudinal studies are needed to corroborate this assumption.

Our analysis did not show significant associations between vigorous and moderate physical activity with lower levels of MP in the back or the arm–hand nor with those PTs who met the current physical activity guidelines. An explanation for this may be that these body areas are not painful due to prolonged static muscle activity as the neck–shoulder muscles are.¹⁴ Thus, other approaches might be more effective for reducing MP. Particularly, high-intensity strength training seems especially effective in reducing MP.^14,15 Therefore, implementing workplace interventions could be an effective strategy to enhance physical activity levels among PTs and reduce MP. Besides the physiological benefits, other positive effects on well-being and on socializing with colleagues would contribute to address more potential factors involved in MP.¹⁵

Limitations

The main limitation of the present study is its cross-sectional design, as it cannot determine causality. Thus, it may be that those with high pain levels avoided doing vigorous activity due to pain. Furthermore, self-reported data could have been influenced by the recall bias, as patients with pain tend to underestimate their self-reported physical activity levels.

Significance

Performing ≥75 min/week of vigorous leisure-time physical activity is positively associated with having lower levels of MP in neck and shoulders among PTs. Moderate leisure-time physical activity did not show any association with lower levels of MP in neck and shoulders. In addition, neither vigorous nor moderate leisure-time physical activity is associated with MP in arm–hand and back.

SO WHAT?

What is Already Known on This Topic?

Leisure-time physical activity is associated with numerous health benefits, including the reduction of musculoskeletal pain (MP) among working populations, as it can increase physical capacity and therefore reduce the relative workload.

What Does This Article Add?

This study provides novel data regarding the potential effect of vigorous leisure-time physical activity on decreasing neck–shoulder MP among physical therapists (PTs), while moderate physical activity showed no association.

What are the Implications for Health Promotion Practice or Research?

These results suggest that promotion of leisure-time vigorous physical activity should be encouraged to PTs to reduce neck–shoulder MP.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Y. Ezzatvar, MSc

J. Calatayud, PhD

References

Anderson

Oakman

. Allied health professionals and work-related musculoskeletal disorders: a systematic review. Saf Health Work. 2016;7(4):259–267.

Vieira

Schneider

Guidera

Gadotti

Brunt

. Work-related musculoskeletal disorders among physical therapists: a systematic review. J Back Musculoskelet Rehabil. 2016;29(3):417–428. doi:10.3233/BMR-150649.

Blond

Rosenkilde

Gram

, et al. How does 6 months of active bike commuting or leisure-time exercise affect insulin sensitivity, cardiorespiratory fitness and intra-abdominal fat? A randomised controlled trial in individuals with overweight and obesity. Br J Sports Med. 2019. doi:10.1136/bjsports-2018-100036.

Doğan

ŞK

Tur

Kurtaiş

Atay

. Comparison of three different approaches in the treatment of chronic low back pain. Clin Rheumatol. 2008;27(7):873–881.

Andersen

Christensen

Holtermann

, et al. Effect of physical exercise interventions on musculoskeletal pain in all body regions among office workers: a one-year randomized controlled trial. Man Ther. 2010;15(1):100–104. doi:10.1016/j.math.2009.08.004.

Blangsted

Sogaard

Hansen

Hannerz

Sjogaard

. One-year randomized controlled trial with different physical-activity programs to reduce musculoskeletal symptoms in the neck and shoulders among office workers. Scand J Work Environ Health. 2008;34(1):55.

Armstrong

Bull

. Development of the World Health Organization Global Physical Activity Questionnaire (GPAQ). J Public Health. 2006;14(2):66–70. doi:10.1007/s10389-006-0024-x.

Garber

Blissmer

Deschenes

, et al. American college of sports medicine position stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise. Med Sci Sports Exerc. 2011;43(7):1334–1359. doi:10.1249/MSS.0b013e318213fefb.

Kuorinka

Jonsson

Kilbom

, et al. Standardised Nordic questionnaires for the analysis of musculoskeletal symptoms. Appl Ergon. 1987;18(3):233–237.

10.

World Health Organization. Global Recommendations on Physical Activity for Health. Geneva, Switzerland: World Health Organization; 2010.

11.

Søgaard

Blangsted

Nielsen

, et al. Changed activation, oxygenation, and pain response of chronically painful muscles to repetitive work after training interventions: a randomized controlled trial. Eur J Appl Physiol. 2012;112(1):173.

12.

Andersen

Blangsted

Nielsen

, et al. Effect of cycling on oxygenation of relaxed neck/shoulder muscles in women with and without chronic pain. Eur J Appl Physiol. 2010;110(2):389–394.

13.

Desouza

Shapiro

Clevenger

, et al. Regular aerobic exercise prevents and restores age-related declines in endothelium-dependent vasodilation in healthy men. Circ J Am Heart Assoc. 2000;102(12):1351–1357.

14.

Larsson

Søgaard

Rosendal

. Work related neck–shoulder pain: a review on magnitude, risk factors, biochemical characteristics, clinical picture and preventive interventions. Best Pract Res Clin Rheumatol. 2007;21(3):447–463.

15.

Jakobsen

Sundstrup

Brandt

Jay

Aagaard

Andersen

. Effect of workplace- versus home-based physical exercise on musculoskeletal pain among healthcare workers: a cluster randomized controlled trial. Scand J Work Environ Health. 2015;41(2):153–163. doi:10.5271/sjweh.3479.