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Feedback Leads to Better Exercise Quality in Adolescents with Patellofemoral Pain

Riel Henrik; Matthews, Mark; Vicenzino, Bill; Bandholm, Thomas; Thorborg, Kristian; Rathleff, Michael Skovdal
Medicine & Science in Sports & Exercise: Post Acceptance: August 25, 2017
doi: 10.1249/MSS.0000000000001412
Original Investigation: PDF Only

ABSTRACTPurposeAdolescents with patellofemoral pain (PFP) do not comply with their exercise prescription, performing too few and too fast repetitions, compromising recovery. We investigated if real-time feedback on contraction time would improve the ability of adolescents with PFP to perform exercises as prescribed.MethodsA randomised, controlled, participant-blinded, superiority trial with a 6-week intervention of three weekly sessions of three elastic band exercises was undertaken. Forty 15 to 19-year-old adolescents with PFP were randomised to real-time BandCizer™-iPad feedback on contraction time or not by a physiotherapist. The primary outcome was the mean deviation from the prescribed contraction time of 8 seconds per repetition. Secondary outcomes included isometric hip and knee strength, Kujala Patellofemoral Scale and Global Rating of Change.ResultsThe mean deviation from prescribed 8 seconds per repetition contraction time was 1.5s (±0.5) for the feedback group, compared to 4.3s (±1.0) for the control group (mean difference: 2.7s (95% CI: 2.2-3.2, P<0.001). Based on total contraction time during the intervention, the feedback group received 35.4% of the prescribed exercise dose whilst the control group received 20.3%. Isometric hip and knee strength increased significantly more in the feedback group compared to controls (mean difference = 1.35 N/kg (95%CI: 0.02-2.68, P=0.047)). There were no significant differences in Kujala Patellofemoral Scale and Global Rating of Change between groups, but the study was not powered for this.ConclusionReal-time feedback on contraction time resulted in the ability to perform exercises closer to the prescribed dose, and also induced larger strength gains.

Purpose

Adolescents with patellofemoral pain (PFP) do not comply with their exercise prescription, performing too few and too fast repetitions, compromising recovery. We investigated if real-time feedback on contraction time would improve the ability of adolescents with PFP to perform exercises as prescribed.

Methods

A randomised, controlled, participant-blinded, superiority trial with a 6-week intervention of three weekly sessions of three elastic band exercises was undertaken. Forty 15 to 19-year-old adolescents with PFP were randomised to real-time BandCizer™-iPad feedback on contraction time or not by a physiotherapist. The primary outcome was the mean deviation from the prescribed contraction time of 8 seconds per repetition. Secondary outcomes included isometric hip and knee strength, Kujala Patellofemoral Scale and Global Rating of Change.

Results

The mean deviation from prescribed 8 seconds per repetition contraction time was 1.5s (±0.5) for the feedback group, compared to 4.3s (±1.0) for the control group (mean difference: 2.7s (95% CI: 2.2-3.2, P<0.001). Based on total contraction time during the intervention, the feedback group received 35.4% of the prescribed exercise dose whilst the control group received 20.3%. Isometric hip and knee strength increased significantly more in the feedback group compared to controls (mean difference = 1.35 N/kg (95%CI: 0.02-2.68, P=0.047)). There were no significant differences in Kujala Patellofemoral Scale and Global Rating of Change between groups, but the study was not powered for this.

Conclusion

Real-time feedback on contraction time resulted in the ability to perform exercises closer to the prescribed dose, and also induced larger strength gains.

Correspondence: Henrik Riel, hriel@dcm.aau.dk, Research Unit for General Practice in Aalborg, Fyrkildevej 7, 9220 Aalborg, Denmark

All authors declare they have no conflicts of interest. No funding was received for this trial. The results of this trial do not constitute endorsement by ACSM and are presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation.

Accepted for Publication: 20 August 2017

© 2017 American College of Sports Medicine