Effect of resistance exercise dose components for tendinopathy management: a systematic review with meta-analysis.

The objective of this study was to investigate potential moderating effects of resistance exercise dose components - including intensity, volume and frequency - for the management of common tendinopathies. The study was conducted through a systematic review with meta-analysis and meta-regressions, using sources that included (but were not limited to) MEDLINE, CINAHL, SPORTDiscus, ClinicalTrials.gov and the ISRCTN Registry. Selection criteria were based on randomised and non-randomised controlled trials investigating resistance exercise as the dominant treatment class, reporting sufficient information regarding two or more components of exercise dose. A total of 110 studies were included in meta-analyses (148 treatment arms (TAs), 3953 participants), reporting on five tendinopathy locations (rotator cuff: 48 TAs; Achilles: 43 TAs; lateral elbow: 29 TAs; patellar: 24 TAs; gluteal: 4 TAs). Meta-regressions provided consistent evidence of greater pooled mean effect sizes for higher intensity therapies comprising additional external resistance compared to body mass only (large effect size domains: βBodyMass:External = 0.50 [95% CrI: 0.15 to 0.84; p = 0.998]; small effect size domains βBodyMass:External = 0.04 [95% CrI: -0.21 to 0.31; p = 0.619]) when combined across tendinopathy locations or analysed separately. Greater pooled mean effect sizes were also identified for the lowest frequency (less than daily) compared with mid (daily) and high frequencies (more than once per day) for both effect size domains, when combined or analysed separately (p ≥ 0.976). Evidence for associations between training volume and pooled mean effect sizes was minimal and inconsistent. The study found that resistance exercise dose is poorly reported within tendinopathy management literature. However, this large meta-analysis identified some consistent patterns indicating greater efficacy on average with therapies prescribing higher intensities (through inclusion of additional loads) and lower frequencies, potentially creating stronger stimuli and facilitating adequate recovery