Do Sex and Age Influence Scapular and Thoracohumeral Kinematics During a Functional Task Protocol?

Abstract

There is mixed evidence on the role that biological sex plays in shoulder biomechanics despite known differences in musculoskeletal disorder prevalence between males and females. Additionally, advancing age may contribute to shoulder kinematic changes. The purpose of this study was to determine if sex and age influenced scapular and thoracohumeral kinematics during a range of functional tasks. Sixty healthy participants aged 19–63 years (30 males; 30 females) completed a functional task protocol while their upper limb motion was recorded. Scapular and humeral angles were calculated and compared with multiple linear regressions to assess the interaction effects of sex and age. Shoulder kinematics were not different between sex and age groups for many of the functional tasks. However, females had lower humeral external rotation in the overhead lift task (15°, P < .001), and less scapular anterior tilt angles in the forward transfer task (6°, P < .001) than males. Age was positively associated with humeral elevation (R2 = .330, P < .001) and scapular rotation (R2 = .299, P < .001) in the Wash Axilla task. There exist some kinematic differences between sex and with advancing age for select functional tasks, which should be considered for musculoskeletal disorder development.

Towards in-field assessment of humeral and scapular kinematics: a comparison between laboratory and field settings using inertial sensors

“…Increasing task constraints, such as movement speed ( 42 , 43 ), could have further minimized the differences between settings. Despite this variation, humeral elevation, humeral rotation, and scapular upward rotation demonstrate minimal differences, similar visual movement trajectories, and similar variability between settings and to previously reported data (i.e., 10°–24°) ( 16 , 31 , 36 , 44 – 47 ). As between-groups comparisons are prevalent in biomechanics, the similarity of the mean and standard deviation of angle waveforms between the lab and field datasets is promising.…”

“…For the lab setting, participants were required to travel to the research lab on the University campus for data collection. Further detail about the lab sample can be found in previous research ( 26 , 31 ). Participants from the lab dataset were selected and matched to participants in field settings based on sex and body height (±5 cm).…”

“…Bilateral scapular calibrations for the double calibration method ( 23 , 25 , 32 ) were completed by aligning a locator ( 23 ) ( Figure 1 ) with the anatomical points of the scapulae to define the scapular orientation in a neutral position and at maximum humeral elevation. This calibration process is described in detail elsewhere ( 23 , 25 , 31 ). IMMU placements and calibrations were conducted by the same researcher across all field participants.…”

“…The primary objective of this study was to determine how humeral and scapular motion measured with IMMUs in different field settings (home, work, sport) compares to motion measured in a lab setting ( 26 , 31 ). It was anticipated that the IMMUs will be able to successfully and accurately measure humeral and scapular kinematics in all in-field settings, as demonstrated by no difference in kinematic outcomes, as well as similar shape and magnitude of waveforms, between the field settings and the lab setting.…”

Comparing and characterizing scapular muscle activation ratios in males and females during execution of common functional movements

“…Ten females and ten males were recruited from a convenience sample ([mean(SD)] age: 24(2) years, height:1.7(0.1) m, weight: 79.1(16.6) kg, 20 right-handed). An a priori between-factors repeated measures ANOVA sample size calculation using an effect size of 0.53 ( Waslen, Friesen & Lang, 2023 ), power set to 0.8, alpha set to .05, 2 groups with 5 measurements (30° increments from 30° to maximum) estimated that a total sample size of 20 participants was required ( Faul et al, 2007 ); observed power in these data was an average of 0.82. Exclusion criteria included (1) under the age of 18, (2) presence of upper body pain or musculoskeletal impairments, (3) previous shoulder surgery, (4) presence of other health-related disorders, (5) inability to raise arms overhead, and (6) allergies to adhesives.…”