Effect of resistance exercise dose components for tendinopathy management: a systematic review

Key points

1. 01Adding external loads (dumbbells, bands, weighted backpack) produced consistently larger effect sizes than body-weight-only exercise across all five tendinopathy sites.
2. 02Lower training frequency (less than once per day) outperformed daily or more-than-daily exercise for both pain/function and quality-of-life outcomes.
3. 03No consistent benefit was found for higher versus lower training volume (sets x reps).
4. 04Most confidence ratings were low to very low, mainly due to extensive heterogeneity and poor intensity reporting in primary studies.
5. 05These patterns held when analyses were repeated separately for each tendinopathy location (rotator cuff, Achilles, lateral elbow, patellar, gluteal).

How it was conducted

Design

Systematic review with meta-analysis and meta-regressions using a four-level nested model

Participants

3953 participants across 110 studies (148 treatment arms) with rotator cuff, Achilles, lateral elbow, patellar, or gluteal tendinopathy

Included studies

110 controlled trials (randomised and non-randomised); searches from 1998 to March 2022

Primary analysis

Meta-regression of standardised mean difference (SMDpre) against exercise intensity, frequency, and volume as moderators

Outcome domains

Disability, function, pain (on loading, over time, unspecified), range of motion (rotator cuff), physical functional capacity, quality of life

Confidence assessment

GRADE approach; overall confidence most commonly rated low, ranging from very low to moderate

What they found

• Higher intensity (external load vs body mass): large-effect outcomes beta = 0.50 (95% CrI: 0.15 to 0.84; p=0.998); small-effect outcomes beta = 0.04 (95% CrI: -0.21 to 0.31; p=0.619)
• Frequency - large-effect outcomes: less-than-daily vs daily beta = -0.50 (95% CrI: -0.88 to -0.11; p=0.992); less-than-daily vs more-than-daily beta = -0.44 (95% CrI: -0.829 to -0.05; p=0.951)
• Frequency - small-effect outcomes: less-than-daily vs daily beta = -0.32 (95% CrI: -0.55 to -0.09; p=0.999); less-than-daily vs more-than-daily beta = -0.21 (95% CrI: -0.42 to -0.00; p=0.976)
• Volume - large-effect outcomes: lower vs higher beta = -0.02 (95% CrI: -0.40 to 0.37; p=0.553); small-effect outcomes beta = -0.14 (95% CrI: -0.35 to 0.09; p=0.782) - no consistent difference
• Combined model (controlling for all three variables) - intensity large-effect outcomes: beta = 0.38 (95% CrI: 0.00 to 0.77; p=0.975); frequency less-than-daily vs daily: beta = -0.60 (95% CrI: -1.1 to -0.13; p=0.993)
• Pooled SMDpre for external-load arms on large-effect outcomes: 1.4 (95% CrI: 1.2 to 1.6) vs body-mass arms: 0.9 (95% CrI: 0.58 to 1.2)
• Pooled SMDpre for less-than-daily frequency on large-effect outcomes: 1.5 (95% CrI: 1.3 to 1.7) vs once-per-day: 1.0 (95% CrI: 0.69 to 1.3)

Limitations

• Most confidence ratings were low or very low due to wide credible intervals and large between-study variance; results should be interpreted cautiously.
• Non-controlled effect sizes were used to maximise available data, meaning unmeasured moderators (intervention duration, adherence, baseline severity) could bias findings.
• Exercise intensity was often poorly reported in primary studies, requiring a crude binary proxy (body mass vs external load) rather than true load quantification.
• Only the primary resistance exercise per study was coded; additional exercises in each programme were not captured, so volume estimates may underrepresent total training load.

Why it matters

For patients

If you have a tendon problem and are doing resistance exercises, using added weights or resistance bands (rather than body weight alone) and spacing sessions out to allow recovery each day may give better results.

For clinicians

When prescribing resistance exercise for tendinopathy, prioritise adding external loads over body-weight-only programmes and prescribe sessions less than once daily to allow adequate musculotendinous recovery; volume prescription requires further evidence before firm dose guidance can be given.

For readers

This is the largest meta-analysis of exercise dose in tendinopathy to date, but evidence quality is mostly low, and the intensity findings rest on a crude binary classification because primary studies rarely report actual loads used.