Sex differences in shoulder performance fatiguability are affected by arm position, dominance and muscle group

• Published in: BMC musculoskeletal disorders 2022-03, Vol.23 (1), p.299-299, Article 299
• Main Authors: Horobeanu, Cosmin, Pullinger, Samuel A, Paulus, Julien, Savoia, Cristian, Wong, Fui Yen, Seurot, Antoine, Croisier, Jean L, Forthomme, Benedicte
• Format: Article
• Language: English
• Subjects: Arm; Coordination; Demographic aspects; Dominance; Fatigue; Fatigue resistance; Female; Females; Gender differences; Health aspects; Human performance; Humans; Interaction; Investigations; Isokinetic; Male; Males; Menstruation; Motor task performance; Muscle contraction; Muscle strength; Muscle Strength - physiology; Muscle, Skeletal - physiology; Muscular performance; Musculoskeletal diseases; Physiological aspects; Rehabilitation; Sex Characteristics; Sex differences; Shoulder; Shoulder - physiology; Shoulder Joint - physiology; Shoulder rotator muscles; Spatial distribution
• ISSN: 1471-2474; 1471-2474
• DOI: 10.1186/s12891-022-05232-w

Injury prevalence data, muscle strength, and fatiguability differ between males and females. In addition, arm spatial orientation affects muscle activation and strength of the shoulder muscles. Nevertheless, little research has been conducted in relation to the shoulder rotator muscles comparing men and women. Therefore, the main aim of of this study was to perform a comparative investigation between two arm spatial orientations (45° and 90° of abduction in the frontal plane) during a fatigue assessment of the internal rotator (IR) and external rotator (ER) shoulder muscles. Secondly, the interaction between sex and dominance with muscular performance was assessed. Forty healthy sedentary participants, 20 males and 20 females took part in this study. Participants performed a fatigue resistance protocol consisting of 30 consecutive maximal concentric contractions of the IR and ER shoulder muscles in a supine position at a speed of 180°/s. The upper limb was abducted to an angle of 45° or 90° in the frontal plane and each participant was tested on the dominant and nom-dominant side, counterbalanced in order of administration. Performance measures of Induced Fatigue (IF; %), Cumulated Performance (C.Perf; J) and Best Repetition (BR; J) were calculated and used for analysis. IF represents the % difference between the amount of work done over the last 3 and first 3 repetitions, BR represents the largest amount of work done during a single contraction, and C.Perf represents the total amount of work done during all repetitions. Muscle group was the only factor to display significant variation when not considering other factors, with higher values for C.Perf (mean difference = 353.59 J, P