Most of us learned slow lowering for Achilles and patellar tendinopathy as a recipe: three sets of fifteen, twice a day, twelve weeks. The recipe still works. What has changed is the explanation, which has less to do with the eccentric contraction and more to do with getting a painful tendon under heavy, progressive load for long enough. Here is where that leaves prescribing, dosing and checking the dose.
Where the protocols came from
Alfredson and colleagues published the Achilles protocol in the American Journal of Sports Medicine in 1998. Fifteen recreational athletes with long-standing midportion tendinosis, mean age 44, did heavy-load eccentric calf training for 12 weeks: heel drops off a step, 3 sets of 15, twice daily, knee straight and then knee bent, adding load as pain allowed. All 15 returned to running. A comparison group of 15 treated conventionally all went on to surgery. Small and unrandomised, but it changed practice.
For the patellar tendon, Young and colleagues (British Journal of Sports Medicine, 2005) randomised 17 elite volleyball players to single-leg squats on a 25 degree decline board or a flat step for 12 weeks. The decline group trained into tendon pain and was more likely to gain 20 VISA-P points at 12 months.
Eccentric-only against heavy slow resistance
Two Danish trials tested the eccentric-only idea directly. Kongsgaard (Scandinavian Journal of Medicine and Science in Sports, 2009) randomised 39 men with patellar tendinopathy to corticosteroid injection, eccentric decline squats, or heavy slow resistance (HSR): squat, leg press and hack squat three times a week, lifted and lowered slowly. All three improved by 12 weeks. At six months the injection group had slipped back, both exercise groups held their gains, and the HSR group was the most satisfied.
Beyer and colleagues (American Journal of Sports Medicine, 2015) randomised 58 people with midportion Achilles tendinopathy to the Alfredson protocol or HSR calf work for 12 weeks. VISA-A and pain improved equally and held at 52 weeks. The numbers that matter for prescribing were secondary: compliance was 78 percent with eccentric work and 92 percent with HSR, and satisfaction at 12 weeks was 80 against 100 percent.
Load matters more than contraction type
A 2019 meta-analysis in the British Journal of Sports Medicine (Murphy and colleagues, seven RCTs) found heavy eccentric calf training better than wait-and-see and traditional physiotherapy, but slightly worse than other exercise programmes, by a margin the authors judged not clinically meaningful. The honest reading: the tendon responds to heavy, slow, progressive load, and whether the lowering phase is isolated or part of a full repetition is a second-order detail.
Isometrics are a different tool. Rio and colleagues (British Journal of Sports Medicine, 2015) showed in a crossover of six volleyball players that heavy isometric quadriceps holds dropped decline squat pain from 7.0 to 0.2 out of 10, with relief lasting at least 45 minutes; isotonic work produced a much smaller drop. That is symptom control, not a replacement for the strength programme.
For the patient-facing version of that distinction, see our guide to isometric holds versus repetitions
Dosing by pain response
Tendon loading is one of the few areas where some pain during exercise is expected. The pain-monitoring model used by Silbernagel and colleagues (American Journal of Sports Medicine, 2007) let 38 patients keep running and jumping during an Achilles loading programme as long as pain stayed in an acceptable range, settled after the session, and was not worse the next morning. They improved as much as the group told to rest for six weeks. The usual ceiling is around 5 on a 0 to 10 scale. In practice:
- Agree the pain ceiling with the patient before the first session and write it on the programme.
- Progress load when sessions sit under the ceiling several times in a row; step back when morning pain or stiffness climbs.
- Track pain with a consistent test (single-leg decline squat or heel raise), not recall.
The twice-daily problem
The Alfredson schedule asks for 180 repetitions a day, every day, for three months. Beyer's 78 percent compliance came from a trial with regular contact. A 2023 systematic review in Healthcare found four of five Achilles trials used the twice-daily, seven-day schedule and concluded the optimal dose is still unknown. HSR at three sessions a week is easier to fit around work, which likely helped its compliance. Either way, progression depends on the dose having been delivered, and "most days" could mean anything from 40 to 90 percent.
Confirming the dose was actually done
When a patient does heel drops or decline squats in a camera-guided KineTrue session, the record shows sessions completed, repetitions in each, and the tempo of the lowering phase, so you can tell whether a plateau reflects a programme that is not working or one done twice a week at a fast tempo. A pain score sits next to the session it followed. Load and progression decisions stay with you.
Pain that has not settled within 24 hours of loading, sharp or sudden pain rather than the familiar ache, new swelling, or a sense that the tendon has given way should prompt reassessment before the programme continues. Suspected partial tear, insertional tendinopathy or a recent corticosteroid injection call for an individual plan, not a standard protocol.