Training and Detraining Effects of a Rehabilitation Program with or without Electro-Cryotherapy in Patients with Anterior Knee Pain: A Randomized Trial

We investigated the effect of ten-sessions (with or without receiving modalities) of training and 4-weeks of detraining in individuals with anterior knee pain (AKP). Thirty patients with AKP (19 males; 11 females; pain duration: 46 months) were randomly assigned to either a rehabilitation program (with or without pre-exercise modality). Quadriceps (strength, activation, power, and endurance) and self-reported functions (pain perception and functional outcomes) were recorded pre- and post-rehabilitation and detraining (4-weeks). The application of electro-cryotherapy did not produce a summative effect on quadriceps or self-reported functions (condition x time: F-2,F-56 < 2.27, p > 0.11 for all tests). Regardless of the modality application (time effect), quadriceps (strength: 12%, p = 0.06; power: 20%, p = 0.006; endurance: 13%, p = 0.0002) and self-reported (pain perception during daily activities: -70%, p < 0.0001; at least: -44%, p = 0.04; at worst: -43%, p < 0.0001; functional outcome scores: 13%, p = 0.0003) functions improved after ten sessions of rehabilitation. The improved values were maintained after 4-weeks of detraining, but functional outcome scores showed an 8% further increase (p = 0.02). Regardless of electro-cryotherapy application prior to voluntary exercises at each session, quadriceps and self-reported function improved after ten sessions of rehabilitation for AKP. Improved functioning lasted throughout a 4-week detraining period.