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Feedback Leads to Better Exercise Quality in Adolescents with Patellofemoral Pain
Henrik Riel1, Mark Matthews, Bill Vicenzino
11Department of Health Science and Technology, Faculty of Medicine, Center for Sensory-Motor Interaction (SMI), Aalborg University, Aalborg, DENMARK; 2Research Unit for General Practice in Aalborg, Department of Clinical Medicine, Aalborg University, DENMARK; 3School of Health and Rehabilitation Sciences, The University of Queensland, St. Lucia, Queensland, AUSTRALIA; 4Physical Medicine and Rehabilitation Research-Copenhagen (PMR-C), Department of Physical Therapy and Department of Orthopedic Surgery, Clinical Research Centre, Copenhagen University Hospital, Amager-Hvidovre, Copenhagen, DENMARK; 5Sports Orthopedic Research Center-Copenhagen (SORC-C), Department of Orthopedic Surgery, Copenhagen University Hospital, Amager-Hvidovre, Copenhagen, DENMARK; and 6Department of Occupational Therapy and Physiotherapy, Aalborg University Hospital, Aalborg, DENMARK.
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 randomized, controlled, participant-blinded, superiority trial with a 6-wk intervention of three weekly sessions of three elastic band exercises was undertaken. Forty 15- to 19-yr-old adolescents with PFP were randomized 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 s 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 s per repetition contraction time was 1.5 ± 0.5 s for the feedback group, compared with 4.3 ± 1.0 s for the control group (mean difference: 2.7 s (95% confidence interval = 2.2-3.2, P < 0.001). On the basis of total contraction time during the intervention, the feedback group received 35.4% of the prescribed exercise dose whereas the control group received 20.3%. Isometric hip and knee strength increased significantly more in the feedback group compared with controls (mean difference = 1.35 N·kg, 95% confidence interval = 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.
