Abstract
Background: Manual wheelchair (MWC) users with spinal cord injuries (SCI) are at a significantly higher risk of experiencing rotator cuff pathology than able-bodied individuals. A deeper understanding of where the arm is used dynamically within the humeral workspace during daily life may help explain why MWC users have higher shoulder pathology rates than able-bodied individuals. The purpose of this study was to report the daily percentage and consecutive durations MWC users and matched able-bodied individuals (controls) spent static and dynamic across the humeral elevation workspace.Methods: MWC users with SCI and controls wore three inertial measurement units on their bilateral arms and torso for 1 or 2 days. The percentages of time and average consecutive duration individuals were static or dynamic while in five humeral elevation ranges (0–30°, 30–60°, 60–90°, 90–120°, and >120°) were calculated and compared between cohorts.Results: Forty-four MWC users (10 females, age: 42.8 ± 12.0, time since injury: 12.3 ± 11.5) and 44 age- and sex-matched controls were enrolled. The MWC cohort spent significantly more time dynamic in 60–90° (p = 0.039) and 90–120° (p = 0.029) and had longer consecutive dynamic periods in 30–60° (p = 0.001), 60–90° (p = 0.027), and 90–120° (p = 0.043) on the dominant arm. The controls spent significantly more time dynamic in 0–30° of humeral elevation (p < 0.001) on both arms. Although the average consecutive static durations were comparable between cohorts across all humeral elevation ranges, the MWC cohort spent a significantly higher percentage of their day static in 30–60° of humeral elevation than controls (dominant: p = 0.001, non-dominant: p = 0.01). The MWC cohort had a moderate association of increased age with decreased time dynamic in 30–60° for both arms.Discussion: Remote data capture of arm use during daily life can aid in understanding how arm function relates to shoulder pathology that follows SCI and subsequent MWC use. MWC users spent more time dynamic in higher elevations than controls, and with age, dynamic arm use decreased in the 30–60° humeral elevation range. These results may exemplify effects of performing activities from a seated position and of age on mobility.
Highlights
It is estimated that over a quarter of a million people have a spinal cord injury (SCI) in the United States, with over 17,000 new cases occurring each year (NSCISC, 2020)
We have previously used IMUs in the free-living environment to capture the humeral elevation workspace during typical days for these two cohorts (Goodwin et al, 2020), and we have investigated the use of a threshold to decipher static from dynamic arm use during daily life (Goodwin et al, 2021)
The results of this study supported our hypotheses that different distribution of static and dynamic periods would be observed between cohorts across humeral elevation ranges, and that increasing age would be associated with decreased dynamic periods
Summary
It is estimated that over a quarter of a million people have a spinal cord injury (SCI) in the United States, with over 17,000 new cases occurring each year (NSCISC, 2020). The arms are required for both mobility and activities of daily living (ADLs) Among this population, the shoulder is the most common site of musculoskeletal pain and pathology, with the reported prevalence ranging between 40 and 70% (Curtis et al, 1999; Dalyan et al, 1999; DysonHudson and Kirshblum, 2004; Alm et al, 2008; Divanoglou et al, 2018). Understanding how MWC users use their arms during daily life and how this differs from controls may aid in understanding why MWC users are at a higher risk for increased shoulder pain and pathology. Manual wheelchair (MWC) users with spinal cord injuries (SCI) are at a significantly higher risk of experiencing rotator cuff pathology than able-bodied individuals. The purpose of this study was to report the daily percentage and consecutive durations MWC users and matched able-bodied individuals (controls) spent static and dynamic across the humeral elevation workspace
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