HSIs remain a major cause of loss of participation across various sports. Functional deficits, such as decreased knee flexor strength, may increase the risk of reinjury if present at the time of RTP. Although eccentric load helps address this issue and reduce the risk of reinjury, the frequent practice of performing exercises pain-free may delay the introduction of this type of exercise.
Forty-six males with acute HSI were randomly allocated to pain-free and pain-threshold rehabilitation groups. The outcome measures were days from HSI to RTP clearance, isometric knee flexor strength, biceps femoris long head fascicle length, fear of movement, and reinjury occurrence at the six-month follow-up. Both groups completed a standardised progressive rehabilitation protocol, differing only in the level of pain allowed during exercise.
Since only two reinjuries occurred during the follow-up period, no conclusions can be drawn about differences in RTP safety between both approaches.
Nevertheless, the study’s findings provide support to the notion that the frequently used approach of making HIS rehabilitation pain-free is not necessarily based on evidence.
> From: Hickey et al., J Orthop Sport Phys Ther 50 (2020) 91-103 (Epub ahead of print). All rights reserved to Journal of Orthopaedic & Sports Physical Therapy. Click here for the online summary.
Expert opinion
Recommendations are frequently made, that early exercises for HIS rehabilitation must be pain-free to improve safety and ensure timely RTP.
Nevertheless, this randomised controlled trial shows that not only there is no difference in RTP time when performing exercises to the pain threshold, but also that the latter approach may indeed bring prolonged benefits in terms of muscle strength and architecture.
From another perspective, this study also shows another way in which pain may not be strictly associated with structural damage.
