The effect of dose components on resistance exercise therapies for tendinopathy management: a systematic review and meta-analysis.

The purpose 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 research was undertaken through a systematic review and meta-analysis, comprising an extensive search of databases and trial registries. Eligibility criteria for selecting studies included randomised and non-randomised controlled trials investigating resistance exercise as the dominant treatment class and reporting sufficient information regarding at least two components of exercise dose (intensity, frequency, volume). Non-controlled standardised mean difference effect sizes were calculated across a range out outcome domains and combined with Bayesian hierarchical meta-analysis models for domains generating large (disability; function; pain) and small (range of motion; physical function capacity; and quality of life) effect size values. Meta-regressions were used to estimate differences in pooled mean values across categorical variables quantifying intensity, frequency and volume. Ninety-one studies presented sufficient data to be included in meta-analyses, comprising 126 treatment arms (TAs) and 2965 participants. Studies reported on five tendinopathy locations (Achilles: 39 TAs, 31.0%; rotator cuff: 39 TAs, 31.0%; lateral elbow: 25 TAs, 19.8%; patellar: 19 TAs, 15.1%; and gluteal: 4 TAs, 3.2%). 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: 0.39 [95% CrI: 0.00 to 0.82; p = 0.976]; small effect size domains (0.09 [95% CrI: -0.20 to 0.37; p = 0.723]) when data were combined across tendinopathy locations or analysed separately. Consistent evidence of greater pooled mean effect sizes was also identified for the lowest frequency (less than daily) compared with mid (daily) and high frequencies (more than daily) for both large effect size domain ( -0.66 [95% CrI: -1.2 to -0.19; p >0.999]; -0.54 [95% CrI:-0.99 to -0.10; p >0.999]) and small effect size domains ( -0.51 [95% CrI: -0.78 to -0.24; p >0.999]; -0.34 [95% CrI: -0.60 to -0.06; p = 0.992]) when data were combined across tendinopathy locations or analysed separately. Minimal and inconsistent evidence was obtained for differences for a moderating effect of training volume. The study concluded that resistance exercise dose is poorly reported within the tendinopathy management literature. However, this large meta-analysis identified some consistent patterns indicating greater efficacy on average with therapies prescribing higher intensities (through the inclusion of additional external loads) and lower frequencies, potentially creating stronger stimuli and facilitating adequate recovery