IMMEDIATE AND SHORT-TERM EFFECTS OF SHORT AND LONG DURATION ISOMETRIC CONTRACTIONS FOR PATELLAR TENDINOPATHY

Review written by Dr Seth O’Neill info

BACKGROUND & OBJECTIVE

Patellar tendinopathy causes disability for many active young adults involved in jumping sports. Management of these individuals in-season is difficult and challenging. Recently heavy long duration isometric contractions of the quadriceps have shown some promise for pain reduction. This study aimed to examine whether shorter duration contractions may be useful and also examined a potential mechanism of effect - transverse strain.

METHODS

The study randomised 16 males to different interventions. The different interventions matched time under tension as this may be important for tendon adaption. Subjects were recruited from volleyball teams, basketball teams and word of mouth. All subjects refrained from their sport for the 4-week intervention period and undertook load-based rehabilitation for their patella tendinopathy for >3months.

The short duration intervention required 24 sets of 10 sec isometric contractions with 20 seconds rest between each repetition whilst the long duration required 6 reps of 40 seconds isometric contractions with 80 seconds rest between repetitions. Both interventions were completed at 30 degrees of knee flexion and exercises were completed 5x per week over the 4-week intervention period. The rate of perceived exertion was used to correspond to 85% Maximum Voluntary Contraction (MVC) during this period.

Single leg decline squat (SLDS) and hopping were used as functional provocation tests to measure pain which was scored on a Visual Analogue Scale (VAS).

RESULTS

Pain changes High levels of adherence were found with 96-100% for both interventions. There were significant reductions in pain immediately after either intervention and a mean reduction of 1.66 on VAS. There was no between group difference.

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