Relationship Between Sitting Time, Physical Function Test, And Physical Function Perception Among Amputees

Individuals with transtibial amputation (TTA) are susceptible to high levels of sedentary behavior (sitting time), and this can lead to detrimental health outcomes. However, accurately measuring sitting time is complex and is not measured during the general care of this population. Physical functional tests are applied regularly, but their relationship with sitting time has yet to be extensively studied. PURPOSE: To determine the relationship between sitting time and performance on 1) the Timed Up and Go (TUG) Test, 2) the L Test of Functional Mobility (L Test), and 3) the Prosthetic Limb User’s Survey of Mobility (PLUS-M). METHODS: Participants were asked to wear an activPAL accelerometer for 7 days (24 h/day) on their non-amputated thigh. , measured their height and weight, and completed the TUG Test and L-Test and a series of questionnaires, including the PLUS-M. Pearson correlation was used to determine the simple correlations. LASSO regression was used to determine the relationship between the TUG Test, L Test of Functional Mobility and sitting time, and PLUS-M and sitting time while including several covariates (sex, age, race, BMI, diabetes status, cancer status, reason for amputation, time of amputation, and time of prosthetic use). RESULTS: A total of 104 adults (27 female, Age: 57.6 ± 13.9 years, BMI: 30.7 ± 5.8 kg/m2) with TTA provided complete data for this study. Average sitting time, TUG Test, L-Test, and PLUS-M scores were 521.51 ± 161.25 [min/day, 13.39 ± 5.71 sec, 30.25 ± 13.09 sec, and 54.06 ± 8.17 T-score, respectively. Sitting time was significantly correlated to TUG Test (r = .51), L-Test (r = .48), and inversely related to PLUS -M (r = -.25). The relationship was maintained when the covariates were included in the regression models. The R2 was .26, .23, and .06 for TUG Test, L-Test, and PLUS-M, respectively. CONCLUSIONS: Sitting time was significantly correlated with the clinical-based functional mobility tests and patient-reported outcome measures of mobility among individuals with TTA and remained significant when covariates were considered. However, the relationship between sitting time and patient-reported outcome measures of mobility was weak.