Audio-biofeedback versus the scale method for improving partial weight-bearing adherence in healthy older adults: a randomised trial.

Purpose: To investigate how audio-biofeedback during the instruction of partial weight-bearing affected adherence, compared to traditional methods, in older adults; and to investigate the influence of individual characteristics.

Methods: The primary outcome measure of this randomised controlled trial was the amount of load, measured as the ground reaction force, on the partial weight-bearing leg. The secondary outcome was the influence of individual characteristics on the amount of load. Included were healthy volunteers 60 years of age or older without gait impairment. Participants were randomly allocated to one of two groups; blinding was not possible. Partial weight-bearing of 20 kg was trained using crutches with audio-biofeedback (intervention group) or a bathroom scale (control group). The degree of weight-bearing was measured during six activities with sensor insoles. A mean load between 15 and 25 kg was defined as adherent.

Results: There was no statistically significant difference in weight-bearing between the groups for all activities measured. For the sit-stand-sit activity, weight-bearing was within the adherence range of 15-25 kg (audio-biofeedback: 21.7 ± 16.6 kg; scale: 22.6 ± 13 kg). 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 level of cognitive function, older age, and higher body mass index were correlated with overloading.

Conclusion: Audio-biofeedback delivered no statistically significant benefit over the scale method. Lower cognitive function, older age and higher body mass index were associated with overloading.

Trial registration: Not applicable due not being a clinical trial and due to the cross-sectional design (one measurement point, no health intervention, no change in health of a person).