A muscle is stronger while it lengthens — 20 to 60 percent more force lowering a weight than lifting one 1. High load, low fuel cost: exactly what a stalled tendon needs.
Tendons don't heal by resting. Pull on them and the cells swap disorganised collagen for aligned fibres; leave them alone and the mess persists for years. The protocols drive sustained force through one tendon via the lowering phase 2.
For tendons, the record is unmatched. Fifteen athletes with chronic Achilles pain, most on surgical lists, did heavy heel drops for twelve weeks; all fifteen returned to running, pain near zero 3. On the knee, a squat down a decline board cut jumper's-knee pain from 74 out of 100 to 28 4.
For hamstrings, the numbers are big. Across 8,459 athletes, teams that added the kneeling curl roughly halved their hamstring injuries 5.
For plain muscle growth, it's a wash — 10 percent versus 6.8 percent for concentric, too small to call real 6. A sensible default, not a shortcut to size.
Pick the version that matches your problem:
Can't face daily reps? Heavy slow resistance (three slow gym sessions a week, both phases loaded) gives the same tendon result, and more people finish it 9.
The timeline is slower than you want. The first month often feels like nothing: tedious reps, pain unmoved. Around week four to six the morning stiffness starts to loosen. By week twelve, most people run without noticing the tendon 10. The hamstring payoff is invisible: a season without the pull that benched two teammates.
The fine print — when to skip it, and what people get wrong
Quitting when the pain stops: pain lifts by week four to six, but collagen remodels through week twelve; stop early and it flares again 10. Never adding load: the point is the weight, not the movement.
"No soreness means it's not working" is false: growth was equal despite very different soreness 6. "It's mainly for muscle" is backwards; it earns its keep at the tendon, and size is a side effect.
This is for chronic pain past two or three months; fresh tears need a physio first. Avoid corticosteroid injections for tendinopathy: they feel great briefly, then leave the tendon weaker, with the worst 12-month outcomes 12.
- 1Hody S, Croisier JL, Bury T, Rogister B, Leprince P (2019). Eccentric muscle contractions: risks and benefits. Frontiers in Physiology. link
- 2LaStayo PC, Woolf JM, Lewek MD, Snyder-Mackler L, Reich T, Lindstedt SL (2003). Eccentric muscle contractions: their contribution to injury, prevention, rehabilitation, and sport. Journal of Orthopaedic & Sports Physical Therapy. link
- 3Alfredson H, Pietilä T, Jonsson P, Lorentzon R (1998). Heavy-load eccentric calf muscle training for the treatment of chronic Achilles tendinosis. American Journal of Sports Medicine. link
- 4Purdam CR, Jonsson P, Alfredson H, Lorentzon R, Cook JL, Khan KM (2004). A pilot study of the eccentric decline squat in the management of painful chronic patellar tendinopathy. British Journal of Sports Medicine. link
- 5van Dyk N, Behan FP, Whiteley R (2019). Including the Nordic hamstring exercise in injury prevention programmes halves the rate of hamstring injuries: a systematic review and meta-analysis of 8459 athletes. British Journal of Sports Medicine. link
- 6Schoenfeld BJ, Ogborn DI, Vigotsky AD, Franchi MV, Krieger JW (2017). Hypertrophic effects of concentric vs. eccentric muscle actions: a systematic review and meta-analysis. Journal of Strength and Conditioning Research. link
- 7Young MA, Cook JL, Purdam CR, Kiss ZS, Alfredson H (2005). Eccentric decline squat protocol offers superior results at 12 months compared with traditional eccentric protocol for patellar tendinopathy in volleyball players. British Journal of Sports Medicine. link
- 8Petersen J, Thorborg K, Nielsen MB, Budtz-Jørgensen E, Hölmich P (2011). Preventive effect of eccentric training on acute hamstring injuries in men's soccer: a cluster-randomized controlled trial. American Journal of Sports Medicine. link
- 9Beyer R, Kongsgaard M, Hougs Kjær B, Øhlenschlæger T, Kjær M, Magnusson SP (2015). Heavy slow resistance versus eccentric training as treatment for Achilles tendinopathy: a randomized controlled trial. American Journal of Sports Medicine. link
- 10Malliaras P, Barton CJ, Reeves ND, Langberg H (2013). Achilles and patellar tendinopathy loading programmes: a systematic review comparing clinical outcomes and identifying potential mechanisms for effectiveness. Sports Medicine. link
- 11Nosaka K, Newton M (2002). Concentric or eccentric training effect on eccentric exercise-induced muscle damage. Medicine & Science in Sports & Exercise. link
- 12Kongsgaard M, Kovanen V, Aagaard P, Doessing S, Hansen P, Laursen AH, Kaldau NC, Kjaer M, Magnusson SP (2009). Corticosteroid injections, eccentric decline squat training and heavy slow resistance training in patellar tendinopathy. Scandinavian Journal of Medicine & Science in Sports. link
დაკავშირებული სახელმძღვანელოში (9)
- — Gluteal and hip tendon pain is exactly the kind of stubborn tendinopathy that responds to loading, not rest.
- — Patellar tendon pain is one of the classic problems eccentric loading resolves.
- — Eccentric loading is exactly the protocol that fixes Achilles and heel pain that rest won't touch.
- — Loading the tendon through its eccentric phase is the engine of rotator cuff rehab that beats surgery.
- — Slow-lowering reps are the core of the rehab that beats rest and cortisone for elbow and wrist tendons.
- — When even slow eccentrics aggravate a joint, light weights with cuffs (BFR) build muscle with almost no load on the sore part.
- — Eccentric loading is the main tendon-rehab driver; collagen peptides are a possible add-on.
- — It's resistance training with the brakes on the lowering half — a small extra gain for lifters.
- — Stretching won't stop you pulling a hamstring; the eccentric Nordic curl roughly halves the risk. Load beats lengthen for prevention.
Eccentric Training
Minimal equipment: a stair (free) for Alfredson; a 25° slant board ($30) for decline squats; a partner or anchored ankles for Nordic curls (Nordic-curl benches $100–300 optional). Most readers can run all three protocols with what's already at home.
For chronic mid-portion Achilles tendinopathy, 12 weeks of heavy eccentric heel drops reduces pain to near-zero in most patients (Alfredson et al. 1998), with comparable results for patellar tendinopathy via the decline squat (Purdam et al. 2004; Young et al. 2005). Heavy slow resistance matches these outcomes (Beyer et al. 2015). For the relevant population this is a substantial, functional, weeks-scale quality-of-life lift; for the broader population, the day-to-day benefit is more modest.
Two well-replicated areas: (1) chronic tendinopathy — multiple RCTs since Alfredson 1998, supported by Kongsgaard 2009 and Beyer 2015 head-to-head HSR comparisons, and synthesised in Malliaras et al. 2013; (2) Nordic hamstring exercise — meta-analysis of 15 trials across 8,459 athletes shows injury risk ratio 0.49 (van Dyk et al. 2019). Clinical community is broadly aligned. Not a 5 because the general hypertrophy/strength superiority over concentric is small and the eccentric-specific claim collapses under load-matched HSR comparisons.
The Alfredson protocol is 180 reps/day, twice daily, for 12 weeks — genuinely demanding to sustain. The Nordic curl programme is more modest (3 ×/week ramp over 10 weeks) but causes meaningful early-week soreness; elite-soccer compliance surveys show ~10% full adherence with player aversion the main barrier (Bahr et al. 2015). General eccentric-tempo lifting integrates into existing resistance training for free.
Eccentric-biased resistance training drives muscle hypertrophy modestly better than concentric-only (10.0% vs. 6.8% mean change across studies; difference not statistically significant) (Schoenfeld et al. 2017) and improves muscle architecture (fascicle length, eccentric strength) (Douglas et al. 2017). Real-but-small long-term contribution to body composition and posture; this isn't the substance's headline effect.
Eccentric training contributes to the longevity benefits of resistance training broadly — sarcopenia prevention, fall reduction in older adults via better braking control (LaStayo et al. 2017; LaStayo et al. 2003), preserved muscle-tendon function. The eccentric emphasis is one ingredient inside the larger strength-training longevity case rather than a standalone large effect.
Indirect: resolving chronic tendon pain or preventing recurring soft-tissue injury removes a real drag on daily activity, and the eccentric-cycling metabolic-cost advantage matters for the deconditioned. Not a primary energy intervention.
Pain resolution in chronic tendinopathy has a real mood payoff after months-to-years of unresolved symptoms; the general exercise-mood effect is also present. Small contribution, not a primary mechanism.