The authors declare that they have no financial or non-financial competing interests.
All three authors (AV, JC and PA) contributed to the design of the study and performed statistical analysis. AV carried out data collection and drafted the manuscript. JC and PA coordinated data collection and helped to draft the manuscript. All authors read and approved the final manuscript.
Work-related musculoskeletal disorders (WMSD) is the most expensive form of work disability. Female sex has been considered as an individual risk factor for the development of WMSD, specifically in the neck and shoulder region. One of the factors that might contribute to the higher injury rate in women is possible differences in neuromuscular control. Accordingly the purpose of this study was to estimate the effect of sex on shoulder joint position sense acuity (as a part of shoulder neuromuscular control) in healthy individuals.
Twenty-eight healthy participants, 14 females and 14 males were recruited for this study. To test position sense acuity, subjects were asked to flex their dominant shoulder to one of the three pre-defined angle ranges (low, mid and high-ranges) with eyes closed, hold their arm in that position for three seconds, go back to the starting position and then immediately replicate the same joint flexion angle, while the difference between the reproduced and original angle was taken as the measure of position sense error. The errors were measured using Vicon motion capture system. Subjects reproduced nine positions in total (3 ranges × 3 trials each).
Calculation of absolute repositioning error (magnitude of error) showed no significant difference between men and women (p-value ≥ 0.05). However, the analysis of the direction of error (constant error) showed a significant difference between the sexes, as women tended to mostly overestimate the target, whereas men tended to both overestimate and underestimate the target (p-value ≤ 0.01, observed power = 0.79). The results also showed that men had a significantly more variable error, indicating more variability in their position sense, compared to women (p-value ≤ 0.05, observed power = 0.78).
Differences observed in the constant JPS error suggest that men and women might use different neuromuscular control strategies in the upper limb. In addition, higher JPS variability observed in men might be one of the factors that could contribute to their lower rate of musculoskeletal disorders, compared to women.
The result of this study showed that shoulder position sense, as part of the neuromuscular control system, differs between men and women. This finding can help us better understand the reasons behind the higher rate of musculoskeletal disorders in women, especially in the working environments.
Punnett L, Wegman DH. Work-related musculoskeletal disorders: the epidemiologic evidence and the debate. Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology. 2004;14(1):13–23. CrossRef
da Costa BR, Vieira ER. Risk factors for work-related musculoskeletal disorders: A systematic review of recent longitudinal studies. Am J Ind Med. 2010;53(3):285–323. PubMed
Zwerling C, Sprince NL, Ryan J, Jones MP. Occupational injuries: comparing the rates of male and female postal workers. Am J Epidemiol. 1993;138(1):46–55. PubMed
Esmail S, Bhambhani Y, Brintnell S. Gender differences in work performance on the Baltimore Therapeutic Equipment work simulator. The American journal of occupational therapy : official publication of the American Occupational Therapy Association. 1995;49(5):405–11. CrossRef
Haward BM, Griffin MJ. Repeatability of grip strength and dexterity tests and the effects of age and gender. Int Arch Occup Environ Health. 2002;75(1-2):111–9. PubMed
Rodrigues PC, Vasconcelos O, Barreiros J, Barbosa R. Manual asymmetry in a complex coincidence-anticipation task: handedness and gender effects. Laterality. 2009;14(4):395–412. PubMed
Sherrington C. The integrative action of the nervous system. Scribner’s Son: New York, NY; 1906.
Vafadar AK, Cote JN, Archambault PS. The effect of muscle fatigue on position sense in an upper limb multi-joint task. Mot Control. 2012;16(2):265–83. CrossRef
Suprak DN, Osternig LR, van Donkelaar P, Karduna AR. Shoulder joint position sense improves with elevation angle in a novel, unconstrained task. Journal of orthopaedic research : official publication of the Orthopaedic Research Society. 2006;24(3):559–68. CrossRef
Vafadar A, Côté J, Archambault P: Inter-rater and Intra-rater Reliability and Validity of Three Measurement Methods for Shoulder Position Sense. Journal of sport rehabilitation 2015. http://dx.doi.org/10.1123/jsr.2014-0309.
Punnett L, Herbert R. Work-related musculoskeletal disorders: Is there a gender differential, and if so, what does it mean? In: Goldman M, Hatch M, editors. Women and Health. San Diego, CA: Academic Press; 2000.
Fedorowich L, Emery K, Gervasi B, Cote JN. Gender differences in neck/shoulder muscular patterns in response to repetitive motion induced fatigue. Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology. 2013;23(5):1183–9. CrossRef
- Sex differences in the shoulder joint position sense acuity: a cross-sectional study
Amir K. Vafadar
Julie N. Côté
Philippe S. Archambault
- BioMed Central
Neu im Fachgebiet Orthopädie und Unfallchirurgie
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