REF-626 · Beyer, Kongsgaard, Hougs Kjær, Øhlenschlæger, Kjær & Magnusson, 2015 · The American Journal of Sports Medicine, · Paper · PubMed
Heavy Slow Resistance matched eccentric training for Achilles tendinopathy at 12 and 52 weeks
With better session compliance (92% vs 78%) and a trend to higher satisfaction at 12 weeks
Participants
n=58 patients with chronic (>3 months) mid-portion Achilles tendinopathy, randomized to eccentric training (ECC) or heavy slow resistance (HSR) for 12 weeks. Outcomes (VISA-A, activity pain on VAS, tendon swelling, neovascularization, satisfaction) at 0, 12 and 52 weeks.
Protocol
Randomized controlled trial analysed by intention to treat (from the abstract): 58 patients with chronic (>3 months) midportion Achilles tendinopathy randomized to eccentric training (ECC) or heavy slow resistance training (HSR) for 12 weeks.
Outcomes at 0 and 12 weeks and at the 52-week follow-up: VISA-A (function and symptoms), tendon pain during activity (VAS), tendon swelling, tendon neovascularization, treatment satisfaction; training-session compliance.
Key Findings
Both groups improved significantly (P < .0001) in VISA-A and pain from 0 to 12 weeks, and the improvements were maintained at 52 weeks; tendon thickness and neovascularization also fell. None of these clinical or structural improvements differed between ECC and HSR.
Satisfaction tended to be higher with HSR at 12 weeks (100% vs 80%, P = .052) but not at 52 weeks (96% vs 76%, P = .10). Training-session compliance was 92% in HSR vs 78% in ECC (P < .005).
Protocol (full text; not checked against the abstract): HSR = heel-raise variations in three weekly sessions with slow repetitions and load progressed from roughly 15RM toward 6RM over the 12 weeks; ECC = the twice-daily heel-drop protocol (REF-625).
Practical Application
In 58 patients with chronic mid-portion Achilles tendinopathy, heavy slow resistance and eccentric training gave equally good, lasting results at 12 and 52 weeks; HSR had higher session compliance (92% vs 78%) and tended to higher satisfaction at 12 weeks. Default to HSR for busy athletes: a few heavy, slow calf-raise sessions per week with progressive load, over about 12 weeks (set/rep details are full text), instead of a twice-daily protocol.
Choose by preference and equipment (eccentric needs a step; HSR needs progressive load) — pick the one the athlete will complete, since compliance was the measurable difference.
Inference, not tested: because both modes worked equally, the stimulus appears to be progressive mechanical load rather than the contraction mode; a slow tempo lets heavy load be handled safely.
Limitations
Single-centre RCT, n=58; mid-portion Achilles only; the satisfaction difference did not reach significance (P = .052) and comes from a modest sample; both arms improve over months, not weeks.
How this entry was checked and changed
Why this level
regraded 2026-09-27 from A: well-powered RCT with n=58 (rubric A- is ≥40; A needs ≥100)
Content correction 2026-09-27
"Higher satisfaction at 12 wk (100% vs 80%)" -> a trend (P = .052), not significant, and gone by 52 weeks (96% vs 76%, P = .10); added compliance 92% vs 78% (P < .005), which is the significant between-group difference.
"HSR needed much less time" removed as a finding (time was not reported in the abstract); HSR protocol numbers (3 sessions/week, 6-s reps, 15RM → 6RM) labelled as full text; "180 reps twice daily" replaced by a pointer to REF-625.
Level A -> A- per the 2026-09-26 rubric (RCT with 40–99 participants).
2026-09-28: added Protocol from the abstract (Europe PMC PMID 26018970).