REF-627 · Rio, Kidgell, Purdam, Gaida, Moseley & Pearce, 2015 · British Journal of Sports Medicine, · Paper · PubMed
A single bout of heavy isometric contractions cut patellar-tendon pain from 7.0 to 0.17 out of 10 for at least 45 minutes in 6 volleyball players
A result whose size did not replicate in a pre-registered crossover of 21 patients, where relief was under 1/10 and no better than isotonic work
Participants
n=6 volleyball players with patellar tendinopathy; a bout of isometric vs isotonic quadriceps contractions compared for immediate and 45-min effects on single-leg decline-squat pain (0–10), maximal voluntary isometric contraction (MVIC) and corticospinal excitability/inhibition.
Protocol
Single-blinded, randomised cross-over study in 6 volleyball players with patellar tendinopathy (from the abstract)
A bout of isometric vs a bout of isotonic muscle contractions, with effects measured immediately and at 45 min
Measures: pain during the single-leg decline squat (0-10), quadriceps MVIC, corticospinal excitability and inhibition; split-plot repeated-measures ANOVA
Key Findings
Isometric contractions reduced decline-squat pain from 7.0 ± 2.04 to 0.17 ± 0.41; isotonic contractions reduced it from 6.33 ± 2.80 to 3.75 ± 3.28 (p < 0.001). Mean reduction 6.8/10 after isometrics vs 2.6/10 after isotonics; the isometric pain reduction was sustained at 45 min, the isotonic one was not.
Isometrics released cortical inhibition (27.53% ± 8.30 → 54.95% ± 5.47); isotonics had no significant effect on inhibition (30.26 → 31.92).
MVIC rose 18.7 ± 7.8% after the isometric bout and stayed higher than baseline and than the isotonic condition at 45 min — pain relief came without a loss of strength.
Protocol (full text, checked 2026-09-28: Table 2): 5 × 45-s isometric knee-extension holds at 60° knee flexion on a Biodex dynamometer at 70% MVC, 2-min recovery.
Practical Application
In 6 volleyball players one bout of heavy quadriceps holds cut decline-squat pain from 7.0 to 0.17/10 for 45 min; that size did not replicate: in a crossover of 21, relief was under 1/10, no better than leg extensions (REF-1147).
Offer heavy isometric holds before practice as one option an athlete may try, not as a reliable pain-reliever.Rio 2017 (REF-1145, n=20) is the one positive in-season RCT (about 1 point more relief per session than isotonic work); in van Ark 2016 (REF-1146) 4-week isometric and isotonic programmes reduced pain equally; Clifford's meta-analysis of 10 RCTs (REF-1149) found isometrics not superior to isotonic exercise immediately or up to 12 weeks; for the Achilles, heavy calf holds gave no relief and the most painful got worse (REF-1148).Not from this paper; the base's own practice: keep holds if that athlete's pain settles, drop them if it flares. The study's own dose, 5 × 45 s at about 70% MVIC, is full text; leg extension, Spanish squat or loaded wall-sit are the base's usual implementations.
Not from this paper; the base's own practice: fit isometrics into a staged patellar pathway — isometrics early as a tolerable load (their pain relief is inconsistent, REF-1149), heavy-slow isotonic for capacity, then energy-storage/plyometric loading and return to sport, progressed by symptom response (Malliaras 2015, DOI 10.2519/jospt.2015.5987; not checked against its abstract).
Isometrics are an adjunct for staying loaded (any pain relief is inconsistent), not a stand-alone cure — capacity-building resistance work changes the tendon (REF-626 for the Achilles analogue).
Limitations
Very small (n=6), single-session, one sport, male jumpers; the size of the analgesia did not replicate: a pre-registered crossover of 21 patients found a 0.9/10 fall, the same after isotonic work and no longer significant by 45 min (REF-1147); isometrics were not superior to isotonic exercise in van Ark 2016 (REF-1146) or in Clifford's meta-analysis of 10 RCTs (REF-1149); heavy calf holds gave no relief in Achilles tendinopathy (REF-1148); only Rio 2017 (REF-1145, n=20, possibly overlapping with van Ark's cohort) found isometrics better in season — present as an option, not a guarantee; acute effect only; the dose is a starting point.
How this entry was checked and changed
Why this level
regraded 2026-09-27 from C: randomized crossover with n=6 (rubric B: crossover under 15); the tiny sample is the reason it sits at the bottom of B, not below it
Content correction 2026-09-27
Isotonic baseline "~7" -> 6.33 (to 3.75); added the mean reductions (6.8 vs 2.6/10), the cortical-inhibition and MVIC numbers from the abstract; the 5 × 45 s at 70% MVIC dose labelled as full text.
Level C -> B per the 2026-09-26 rubric (randomized crossover, n<15 = B); the staged-pathway advice labelled as the base's own practice; Sport line normalised.
2026-09-28: added Protocol from the abstract (Europe PMC/PubMed PMID 25979840).
2026-09-28: lines labelled "full text; not checked" read against the open-access full text (BJSM Online First PDF on figshare): 1 confirmed (5 × 45 s at 70% MVC; 60° and 2-min recovery added), 0 corrected, 0 removed.
Revision 2026-10-16: folded REF-1145 (Rio 2017), REF-1146 (van Ark 2016), REF-1147 (Holden 2020), REF-1148 (O'Neill 2019) and REF-1149 (Clifford 2020).Title, Applicability, the first Practical bullet, the staged-pathway line, the adjunct line and Limitations now say the analgesia did not replicate in Holden's pre-registered crossover (0.9/10, no different from isotonic work, gone by 45 min), was absent for the Achilles in O'Neill, and was not superior to isotonic exercise in van Ark or in Clifford's meta-analysis; Rio 2017 is named as the one positive in-season RCT.The card no longer recommends holds as an in-session pain-reliever. Level unchanged at B.