Audio-Biofeedback Versus the Scale Method for Improving Partial Weight-Bearing Adherence in Healthy Older Adults: a Randomised Trial

Background: Adherence to partial weight-bearing prescription is poor, especially amongst older adults taught with traditional methods. Reasons for this remain unclear and improvements to the instruction of partial weight-bearing are necessary. This randomised controlled trial aimed to investigate how the use of audio-biofeedback during the instruction of partial weight-bearing affected adherence to a weight-bearing limit of 20 kg, compared to the scale method, in older adults. Methods: The primary outcome measure was the amount of loading of the partial weight-bearing leg during functional mobility activities, measured as the ground reaction force in Newtons and converted to kilograms. Included were healthy volunteers 60 years of age or older without gait impairment. Participants were randomised into two groups. Blinding was not possible. Partial weight-bearing of 20 kg using crutches was trained with audio-biofeedback (intervention group) or a bathroom scale (control group). The degree of weight-bearing was measured during functional mobility activities (standing, sit-stand-sit, step-up/down and walking) with OpenGo sensor insoles (Moticon ReGo AG, Munich, Germany). A mean load between 15-25 kg was defined as adherent. Weight, height, cognitive function and grip strength were measured. Linear regression analyses were performed to identify factors influencing adherence. Results: Thirty volunteers (16 females, 71±6 years, weight 74±17 kg; height 169±9 cm) participated in the trial, fifteen participants in each group. There were no drop-outs. There was no statistically significant difference in weight-bearing between both groups for the activities measured. For the sit-stand-sit activity, weight-bearing for the audio-biofeedback group (21.7±16.6 kg) and the control group (22.6±13 kg) were within the target range. For standing, loading was below the lower threshold (10±7 vs. 10±10 kg). Weight-bearing was above the upper threshold for both groups for: walking (26±11 vs. 34±16), step-up (29±18 vs. 34±20 kg) and step-down (28±15 vs. 35±19 kg). Lower cognitive function, older age, and higher body mass index were associated with poorer adherence to partial weight-bearing. There were no incidents or harms during the trial. Conclusion: Audio-biofeedback delivered no statistically significant benefit over the scale method. Lower cognitive function, older age and higher BMI were associated with poorer adherence to partial weight-bearing instructions. Trial registration Not applicable due to the cross-sectional design (one measurement point, no intervention).