Posture-Related Behaviors Between Age Groups In Males Following Total Knee Replacement

PURPOSE: To examine differences in objectively measured sedentary time in posture-related behaviors (upright, standing, sitting, and stepping) based on age in males following total knee replacement (TKR). METHODS: Male adults (n = 26) with an upcoming or recent TKR ≤1 year (90% white, 64.5 ± 9.9 years, BMI: 32.2 ± 6.2 kg/m2) from a sedentary reduction intervention were included in this secondary analysis. At baseline, participants wore an accelerometer on their non-surgical thigh for 7 consecutive days. The accelerometer provided the following posture-related sedentary behaviors in minutes/day: upright time, standing time, sitting time, and stepping time. Valid wear time required 24 hours of continuous use on 4 of 7 wear days. Male participants were categorized based on age at the time of informed consent using age groups of ≥65 years and < 65 years. Independent t-tests compared differences in these measures between male age groups with TKR. Cohen’s d was used to interpret the magnitude of effect sizes among each sedentary behavior between male age groups with TKR. RESULTS: Mean differences with effect sizes between groups can be found in Table 1. Overall, male participants had 6.6 ± .8 valid days of accelerometer use with no significant differences between groups (P = 0.86). Males ≥65 years with TKR spent significantly less upright time per day than males <65 years with TKR (P = 0.03, Cohen’s d = -.93). Large effect sizes were observed for standing time (P = 0.052, Cohen’s d = -.80), sitting time (P = 0.06, Cohen’s d = .78), and stepping time (P = 0.07, Cohen’s d = -.75) indicating that males ≥65 years with TKR spend less time standing, more time sitting, and less time stepping compared to males <65 years with TKR. CONCLUSION: Adults males aged ≥65 years with a history of TKR ≤1 year ago spent less time upright per day relative to males with TKR that were < 65 years. More research is needed to understand the relationship between posture-related behaviors and other health-related outcomes. Table 1: - Differences in Posture-Related Behaviors Between Age Groups In Males With TKR Variables Males ≥65 years (n=12) Males <65 years (n=14) P Cohen’s d Posture-Related Behaviors Mean (SD) Mean (SD) Upright time (min/day) 238.7 (75.1) 312.2 (82.2) .03 -.93 Standing time (min/day) 166.3 (53.6) 218.3 (72.9) .052 -.80 Sitting time (min/day) 690.4 (81.6) 622.0 (92.4) .06 .78 Stepping time (min/day) 72.4 (34.7) 93.9 (22.0) .07 -.75