The Acute Effect of Isometric Versus Isotonic Resistance Exercise in Patients With Patellar Tendinopathy
Condition: Patellar Tendinitis
MeSH terms: Tendinopathy
Study type: Interventional

Summary: 
      The purpose of this study is to compare the acute effects of two different types of
      resistance exercise (isometric versus isotonic) on exercise induced hypoalgesia during an
      aggravating activity, in participants with patellar tendinopathy.
    

Detailed description: 
      Exercise is a commonly prescribed treatment for patients with musculoskeletal pain, and is
      effective in treating tendon pain. It is well documented, that an acute bout of aerobic or
      resistance type exercise reduces sensitivity to pain in healthy individuals. Therefore the
      efficacy of exercise as an intervention may be partially due to the analgesic effect of
      exercise, also termed exercise-induced hypoalgesia (EIH).

      For tendinopathies, high load resistance exercise is frequently used during rehabilitation.

      However, the optimal mode and dosages required for reducing pain in patients with
      tendinopathies is unknown. Understanding the effect of different forms of exercise on pain
      may help optimize the prescription of exercise for pain management.

      A recent study by Rio and colleagues documented the acute effect of two different forms of
      resistance exercise in patients with patellar tendinopathy. The study compared, isometric
      resistance exercise (static muscular contractions), in comparison to isotonic resistance
      exercise (dynamic contractions) and found that isometric exercise induced greater
      participantive pain relief in response to an aggravating task. This study was the first to
      compare the analgesic effect of different forms of resistance exercise in patients with
      tendinopathy.

      Although the results appear promising, a limitation of the study was that it did not quantify
      the effect of the different exercises on measures of pain sensitivity as in previous studies
      examining EIH.

      Purpose The purpose of this study is to compare the acute effects of two different types of
      resistance exercise (isometric versus isotonic) on exercise induced hypoalgesia during an
      aggravating activity, in participants with patellar tendinopathy.

      Hypothesis The primary hypothesis is that isometric exercise will induce greater pain
      relief/reduction during an aggravating activity in comparison to isotonic exercises.

      Study Design and Methods The proposed study is a participant blinded, randomised crossover
      superiority trial, to examine acute effect of isometric versus isotonic resistance exercise
      on pain in patients with patellar tendinopathy. The trial will be pre-registered on
      clinicaltrials.gov before inclusion of participants commences.
    

Intervention name(s): Isotonic Exercise; Isometric exercise
Intervention type(s): Other; Other
Intervention description(s): Participants will complete dynamic leg extension in a leg extension machine with a range of motion from approximately 90 degrees flexion to full extension. Each repetition will be completed with a 3s concentric contraction, 0s isometric and 4s eccentric contraction.This will be repeated for 8 repetitions and for 5 sets with 2 minutes rest between each set, as per Rio and colleagues. The load used during the isotonic exercise will be equivalent to participants 8 repetition maximum, which will be determined by an experienced tester in a standardised manner according to NSCA guidelines.; Participants will complete isometric quadriceps exercise, where they must hold a load statically for 45s with their knee in 60° flexion. This will be repeated for 5 sets with 2 minutes rest between each set. A load of 70% of the maximal voluntary isometric contraction (MVIC) will be used. MVIC will be assessed in an isokinetic dynamometer as per Rio and colleagues. Participants will be seated in a stable position in the dynamometer with the knee at 60° of knee flexion. First they will be familiarised with the procedure. Standardised instructions will be issued for participants to perform a maximal effort knee extension against the dynamometer for 3seconds. After a short break, the test will be repeated three times and the MVIC will be peak torque recorded during these three efforts.
Other intervention name(s): resistance exercise
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: The proposed study is a participant blinded, randomised crossover superiority trial, to examine acute effect of isometric versus isotonic resistance exercise on pain in patients with patellar tendinopathy.
Masking: Single (Participant)
Primary purpose: Other
Keywords: Patellar tendinopathy