6-week Gait Retraining Elicits An Increase In Peak Vertical Ground Reaction Forces In Acl-reconstructed Individuals

It remains unknown if real-time gait biofeedback (RTGBF) can elicit retention of increased peak vertical ground reaction force (vGRF) in those with anterior cruciate ligament reconstruction (ACLR) who often exhibit abnormally low peak vGRF. PURPOSE: Determine the effect of a 6-week, 18-session RTGBF intervention used to cue an increase in peak vGRF to 1.12 body weights (BW), compared to sham RTGBF on retention of vGRF profiles. METHODS: ACLR participants with an average overground peak vGRF≤1.09BW were randomized into RTGBF or sham groups (RTGBF n = 12, 90% female (F); sham n = 12, 75% F). Visual RTGBF integrated with a split belt force-measuring treadmill was used to drive the RTGBF. The RTGBF goal was to match bilateral step-by-step peak vGRF depicted as the height of blue bars to a red target line (at 1.12BW). The sham RTGBF had an identical visual display to the RTGBF except the sham target corresponded to the individual’s habitual average step length collected at baseline (B). We collected vGRF at B, 6-week (6 W), and 8-week (8 W) follow-ups and conducted repeated measures ANOVAs to assess differences in peak vGRF for each group over time. RESULTS: 4 participants did not complete both post-tests (RTGBF n = 8; sham n = 12). There were no statistical differences between groups for the entire cohort. Following completion of the initial analyses, we determined a portion of people (n = 2) who screened into the study with a peak vGRF≤1.09BW during overground walking demonstrated peak vGRF>1.12BW during the first treadmill session-indicating they would be cued to decrease peak vGRF during the intervention rather than the anticipated increase in vGRF intended. Thus, we conducted a post hoc sensitivity analysis including only individuals (RTGBF n = 7, sham n = 11) with a treadmill peak vGRF≤1.09. A time × group interaction was observed in this sub-analysis (F2,36 = 3.51, p = .04). RTGBF led to an increase in peak vGRF (B: 1.05BW ± 0.04BW; 6 W: 1.09BW ± 0.03BW; 8 W: 1.10BW ± 0.05BW) while there was no change observed for the sham (B: 1.08BW ± 0.05BW; 6 W: 1.08BW ± 0.04BW; 8 W: 1.08BW ± 0.05BW) with a medium effect between groups at 8 W (d = 0.48). CONCLUSION: RTGBF gait retraining may effectively elicit a change in vGRF profiles two weeks after completion of a RTGBF intervention in ACLR individuals who display aberrantly low peak vGRF when walking on a treadmill. Arthritis Foundation