Objectively measured movement behaviors of adult transtibial prosthesis users

Understanding real-world movement behavior is essential for optimizing rehabilitation for people with lower limb amputation, yet clinical measures reflect performance mainly in controlled settings. Free-living studies are often small, and individuals with transtibial amputation generally demonstrate reduced physical activity and high sedentary time relative to population norms. Clinicians lack robust reference values that reflect daily-life behavior. Therefore, the aim of this study was to characterize 24-hour (h) movement behavior patterns in a larger cohort than typically reported and establish percentile-based reference values to support individualized rehabilitation.

A cross-sectional, observational design using objective monitoring of free-living movement behaviors was implemented. Ninety-six adults with unilateral transtibial amputation were recruited from prosthetic clinics across the United States (mean age 58±13.5 years; 24 female). Participants self-reported their age, sex, ethnicity, diabetes status, amputation etiology, years of prosthesis use, and the age of their prosthesis. Height and weight were measured, and amputation-adjusted BMI was calculated. Participants wore activPAL and Fitbit devices for seven days to quantify steps, sedentary time, prolonged sedentary bouts (>1 h), standing time, stepping time, sleep duration, and sit-to-stand transitions. Percentile distributions summarized movement behaviors, and time-use compositions described daily allocation of sedentary, standing, stepping, and sleep time.

Participants averaged 4,712 steps/day with activPAL and 5,815 steps/day with Fitbit. Median sedentary time was 616 minutes (min) (10.26 h)/day, with mean sleep duration of 500 min (8.33 h)/night. At the extremes, the 5th percentile accumulated 701 steps/day with 386 min (6.43 h) of sedentary behavior, whereas the 95th percentile accumulated 10,691 steps/day and 905 min (15.08 h) of sedentary behavior. Stepping time ranged from 11 to 164 min (2.73 h)/day. Significant differences (p<0.006) were observed by functional mobility classification, obesity status, and diabetes status.

Free-living movement behavior showed substantial variability and pervasive sedentary time. Percentile-based benchmarks provide clinically useful context for assessing mobility and informing personalized rehabilitation targets.