Heavy slow resistance training for tendinopathy: how to prescribe the load

Heavy slow resistance training is a 12 week program of two or three slow, heavy lifts for the painful tendon, two or three days a week, with each repetition taking about 6 seconds, 3 seconds up and 3 seconds down. The trials that tested it agree on the tempo and the length of the program and disagree about the load ladder. That is the honest state of tendinopathy exercise prescription: the papers with the best designs tell you what they did, not what you should do, and the pages that hand out tempo, sets and pain numbers with confidence mostly cite nobody.

Every loading mode here comes with the trial that produced it and the population that trial studied, because that is what tells you where the specification stops and your own protocol choice begins. The pain rules live in the pain monitoring model guide and the heel drop protocol lives on the heel drops page, so neither is repeated here.

What is heavy slow resistance training?

It is slow, heavy, bilateral or unilateral machine or barbell work for the muscle group that loads the tendon, done on a fixed tempo so that the tendon spends a long time under tension in both directions. Two Copenhagen trials put it on the map, one in the patellar tendon and one in the Achilles, and both ran for 12 weeks.

Kongsgaard and colleagues randomized 39 men with patellar tendinopathy to a corticosteroid injection, eccentric decline squats or heavy slow resistance. All three groups improved on the VISA-p and on pain by week 12. At the half-year follow-up the exercise groups had held their gains and the injection group had lost them, the heavy slow resistance patients were the most satisfied, and in that group tendon swelling had fallen by 12 percent, give or take 13, and vascularization by 45 percent, give or take 23.

Beyer and colleagues then compared the two exercise approaches directly in 58 patients with chronic midportion Achilles tendinopathy. Both groups improved on the VISA-A and on pain during activity, both held those gains at 52 weeks, and neither beat the other. What did differ was how the two programs felt to do. Session compliance was 92 percent with heavy slow resistance and 78 percent with eccentrics, and satisfaction at 12 weeks was 100 percent against 80 percent, which fell short of significance.

The Beyer full text is behind a subscription, so that protocol's session structure is not stated on this page. The Kongsgaard methods are readable in an archived copy of the publisher's page, so the original ladder is in the table below alongside the trials whose full texts are open.

Tendon loading exercises: what each protocol actually specifies

Protocol	Who it was tested on	Frequency and length	Load	Tempo
The original heavy slow resistance (Kongsgaard 2009)	39 recreational male athletes aged 18 to 50 with patellar tendinopathy, mean symptom duration 19 months	12 weeks, squat, leg press and hack squat, 3 sessions a week with one supervised, 4 sets per exercise, 2 to 3 minutes between sets	15RM in week 1, then 12RM in weeks 2 and 3, 10RM in 4 and 5, 8RM in 6 to 8, 6RM in 9 to 12, from full extension to 90 degrees of knee flexion	6 s per repetition, 3 s each phase
TEREX heavy slow resistance (Agergaard 2026)	52 sports-active adults aged 18 to 60 with patellar tendinopathy	12 weeks, leg press and knee extension, 1 or 3 days a week, 3 sets rising to 4 after 6 weeks, 1 to 2 minutes between sets	15 repetition maximum (about 60% of 1RM), progressing to 10RM (about 75%) over the first 3 weeks	6 s per repetition, 3 s each phase
Heavy slow resistance (Xiao 2024)	17 college students per arm with patellar tendinopathy, mostly men	8 weeks, 3 sessions a week, squat, leg press and Bulgarian squat, 4 sets of each with 2 minutes between sets	12RM in weeks 1 and 2, 10RM in 3 and 4, 8RM in 5 and 6, 6RM in 7 and 8, above 70% of 1RM throughout	3 s eccentric and 3 s concentric, 6 s in total
Progressive tendon loading, stages 1 and 2 (Breda 2021)	76 athletes aged 18 to 35 with patellar tendinopathy, median symptom duration 2 years	24 weeks in four stages; isometrics daily, isotonics every second day	Isometric 5 holds of 45 s at 70% of maximum voluntary contraction at 60 degrees of knee flexion; isotonic from 4 sets of 15 to 4 sets of 6 as load rises	Not specified
Progressive tendon loading, stages 3 and 4 (Breda 2021)	As above	Energy storage work every third day, sport-specific work every 2 to 3 days	3 sets of 10 on both legs progressing to 6 sets of 10 on one leg	Not specified

Read the population column before you borrow a row. Every protocol in that table was tested on a patellar tendon, all four trials recruited sports-active people, and two of them recruited nobody over 35. The Achilles evidence comes from the Beyer trial and from the network meta-analysis below, and the gluteal, hamstring and elbow tendons have no protocol of this quality at all, which is why the greater trochanteric pain program and the tennis elbow program build their load from the same principles rather than from a published ladder.

The exclusions matter as much as the ages. The staged loading trial, which has the clearest protocol of the four, kept out anyone with inflammatory joint disease or familial hypercholesterolemia, anyone who had had a corticosteroid injection in or near the tendon in the previous year, anyone using a medicine with a putative effect on the tendon in that year, naming fluoroquinolone antibiotics as its example, and anyone with a previous rupture of that tendon. None of those patients has been tested on this ladder, and in clinic the injection and the antibiotic are the two commonest reasons to build the load more slowly than the paper did.

How often should you prescribe isometrics for tendinopathy?

Daily, if you are following the staged protocol. If you are not, they are a fallback and not the centerpiece. In the Breda program, isometrics were the whole of stage 1 and were done every day: a single-leg leg press or leg extension, 5 holds of 45 seconds at 70 percent of a maximum voluntary contraction, at 60 degrees of knee flexion. Patients moved up once a single-leg squat provoked 3 or less out of 10 on a visual analog scale and the stage had been done for at least a week. Both had to be true.

The reputation isometrics have for taking pain away rests on a smaller study than most clinicians realize. Rio and colleagues tested a single bout in 6 volleyball players with patellar tendinopathy, crossing them over between isometric and isotonic contractions. Pain on the single leg decline squat fell from 7.0 to 0.17 out of 10 after the isometric bout and from 6.33 to 3.75 after the isotonic one, the relief was still there 45 minutes later only after the isometrics, and maximum voluntary contraction rose by 18.7 percent. Six players is six players, and the effect has not held up as reliably in later work.

The UK Defence Rehabilitation panel, 21 clinicians voting on a modified Delphi, landed on a more modest position: for the patellar tendon, isometric and isotonic contractions are equally good at reducing pain in the short term, and for the Achilles, isometrics are the choice when a patient cannot tolerate another contraction type (Judd 2026). That panel was voting about military personnel, so the population is young and fit. In clinic the practical use is the irritable tendon in front of you, where a 45 second hold in a comfortable range is something the patient can do today and a loaded lift is not. Our isometric calf raise hold and wall sit pages carry the patient-facing versions.

Do eccentric exercises still have a place in tendinopathy?

Yes, and the question is better framed as what you give up by choosing them. In the Breda trial the staged loading program beat eccentric decline squats on the VISA-P at 24 weeks, 28 points against 18, an adjusted between-group difference of 9 points with a confidence interval running from 1 to 16. Hold that 9 against the trial's own yardstick: it was powered to detect a minimum clinically important difference of 13 points on the VISA-P, so the winning margin was real and still smaller than the difference its authors had called clinically important. Return to sport was 43 percent against 27 percent, which did not reach significance, and adherence was poor in both arms, 40 and 49 percent.

One detail in that trial deserves more attention than the headline. The eccentric arm was told to work at 5 or more out of 10 on a visual analog scale and the staged arm to stay at 3 or less, so the comparison was between two pain rules as much as between two loading modes. If you prescribe decline squats with a pain ceiling rather than a pain target, you have not run the protocol that lost.

For the Achilles tendon the living network meta-analysis is the better guide. Across 29 trials and 42 treatments, 86 percent of the trials in midportion disease, every active treatment class looked better than wait and see at 3 months, and at 12 months exercise alone was comparable to exercise plus injection, exercise plus a night splint, and injection therapy. Certainty was very low to low, and 22 of the 29 trials were at high risk of bias with none at low risk.

One gap in it matters before you quote that review at an insertional problem: no network meta-analysis could be run for insertional Achilles tendinopathy at all, because the trials were not there, so the comparative evidence covers the midportion and stops. The authors concluded that there is no clinically relevant difference between active treatments and that a calf exercise program is a sensible place to start because it is cheap and does little harm (van der Vlist 2021). The staged version for patients is the Achilles tendinopathy program, and the eccentric calf raise and calf raises pages hold the technique.

Where the published prescription runs out

Progression runs out first. No trial has tested one progression rule against another, so the step from 4 sets of 15 to 4 sets of 6, or from 12RM to 6RM, is a protocol choice rather than a finding. The Breda trial at least wrote its rule down: at least a week at the current stage, plus 3 or less out of 10 on a single-leg squat as the provocation test, before moving up. Borrowing that rule is defensible; calling it evidence for a threshold is not.

Dose comes next, and the surprise in it runs the opposite way to the one most clinicians expect. In the TEREX trial, patients who did the same 12 week program once a week did as well as those who did it three times a week on the VISA-P, on pain, and on a rise in isokinetic peak torque of 17 percent in the once-weekly group and 19 percent in the three-times group, and the once-a-week group turned up more often, 93 percent of sessions against 81 percent. One condition came with that result: both groups were also told to stop running, jumping and other impact activity unless tendon pain stayed below 3 out of 10, so the once-weekly dose was tested alongside a cut in everything else the tendon was doing, not on its own.

The Defence panel reached the same conclusion for the Achilles from the other direction, agreeing that lower volume protocols are as effective as higher volume ones. Neither finding says that less is better. Both say that the week you can actually get done is a legitimate thing to prescribe.

Then the pain ceiling. Each protocol sets its own and they do not agree with each other: 3 or less out of 10 on a single-leg squat in the staged program, 5 or more during the exercise in its eccentric comparator, under 3 in the Xiao trial provided it did not climb in the sessions that followed, and in the original Kongsgaard protocol pain during the lift was allowed as long as pain and discomfort did not increase after training stopped. The Defence panel went further and agreed that heavy slow resistance and staged loading progressed by functional capacity give better outcomes than protocols driven by pain scores (Judd 2026). So pick a ceiling, write it in the patient's words, keep it the same across the episode, and let the step up be decided by what the tendon can do rather than by the number alone.

None of these ceilings applies to bone, so read the bone stress injury paragraph at the end of this guide before you give a runner a pain allowance. The pain monitoring model guide sets out where those numbers came from and what they do not cover.

How to write the dose into a home program

Put the tempo in the cue, because it is the part patients drop first. "Three seconds down, three seconds up, counted out loud" survives the trip home better than "slow and controlled" does. Then name the load in a way the patient can reproduce without a 1RM test: the weight at which the last repetition of the set is hard but clean, with 1 or 2 left in reserve. That is roughly where a 10 to 12 repetition maximum sits.

Many programs start at 2 to 3 sets of 10 to 15 with a 6 second repetition, 2 or 3 days a week, and add load rather than repetitions once the set feels easy two sessions running. Your physio will adjust this, and after surgery or a tendon repair the surgical team's protocol decides it instead. The FITT principle guide covers how to write each letter down, and the progression guide covers the step up and the step back.

Record the actual load and the actual sets, not the prescription, so you can tell a flare from a gap in training. And give the patient one morning test for the tendon, the same one every time. The whole pain rule rests on that check. For runners, the loading plan sits alongside the criteria in the return to running guide, and the patellar tendinopathy program shows a staged version a patient can follow alone.

When to stop, whatever the protocol says

A tendinopathy protocol covers the familiar pain of the tendon you are treating. These signs override the dose, and every patient on a loading program should know them. Each one means stop and get help:

1. Chest pain or pressure, dizziness or feeling faint, a racing or irregular heartbeat, or being far more out of breath than the effort should cause.
2. A sudden pop or snap at the back of your ankle or heel, a feeling that someone kicked you there, or sudden pain there after which you cannot push off or rise onto your toes on that leg. Stop, take the weight off that leg carefully and go to an urgent care center or emergency department the same day, even if you can still walk, as this can be a torn Achilles tendon.
3. Your calf or thigh becomes swollen, warm, tender, red or darker than usual, or has a throbbing or cramping pain that feels different from normal muscle ache. Stop and get medical advice the same day, as this can be a blood clot. If you are also short of breath or have chest pain, call emergency services.
4. Pins and needles, numbness or weakness in an arm or leg that does not go away after you stop. Get medical advice the same day. If one side of your face or body suddenly goes numb or weak, or your speech becomes slurred or muddled, call emergency services, even if it goes away.
5. Sharp pain during an exercise, a joint that gives way, new swelling, or pain that is still worse a few days after you drop back a step. Stop that exercise and check with your physio before you do it again.

If chest pain, pressure or tightness does not ease quickly when you rest, spreads to your arm, neck, jaw, stomach or back, or comes with sweating, feeling sick, feeling light-headed or being short of breath, call emergency services straight away, as this can be a heart attack. If it eases quickly and none of these happen, get medical advice the same day, and do not exercise again until you have been checked. If you faint while exercising, call emergency services, even if you feel fine again quickly.

One tissue needs naming separately, because a runner with a bone problem often arrives believing it is a tendon. A bone stress injury has no pain allowance at all. Pain at one spot on a bone that the patient can point to with a finger, bone pain at rest or at night, or pain on hopping at that spot means stop the loading program, not monitor a number, and have the bone assessed with imaging. The sites that get mistaken for a tendon problem are the inner shin behind the tibialis posterior tendon, the heel bone under the Achilles insertion, the navicular, the base of the fifth metatarsal, and the front of the shin. Groin, hip or thigh pain of this kind is the urgent one, because a femoral neck stress fracture can displace, so stop weight-bearing loading and refer for urgent imaging within days, not at the next review.

Suspect bone sooner in a runner who has had a stress fracture before, who has lost weight, is eating less than training demands or has missed periods, who takes steroid tablets, or who has been told their bone density is low.

The short version

Heavy slow resistance training means about 6 seconds a repetition, two or three lifts for the tendon, 2 or 3 days a week for 12 weeks, with load climbing as repetitions fall. It works about as well as eccentric loading and patients stick with it better. The staged loading program has the best single trial result in the patellar tendon, and its stage 1 is daily isometrics at 70 percent of a maximum hold. Everything past that, the progression rule, the weekly dose and the pain ceiling, is a choice you make and write down, because no trial has compared the options.

References

1. Kongsgaard M, Kovanen V, Aagaard P, Doessing S, Hansen P, Laursen AH, Kaldau NC, Kjaer M, Magnusson SP. Corticosteroid injections, eccentric decline squat training and heavy slow resistance training in patellar tendinopathy. Scandinavian Journal of Medicine and Science in Sports. 2009;19(6):790-802. https://doi.org/10.1111/j.1600-0838.2009.00949.x
2. Beyer R, Kongsgaard M, Hougs Kjær B, Øhlenschlæger T, Kjær M, Magnusson SP. Heavy slow resistance versus eccentric training as treatment for Achilles tendinopathy: a randomized controlled trial. American Journal of Sports Medicine. 2015;43(7):1704-1711. https://doi.org/10.1177/0363546515584760
3. Agergaard AS, Svensson RB, Hoeffner R, Gillani SZ, Magnusson SP. Extended restitution between sessions does not enhance the benefits of 12 weeks exercise-based treatment for patellar tendinopathy: a randomized controlled clinical trial (the TEREX trial). Scandinavian Journal of Medicine and Science in Sports. 2026;36(3):e70235. https://doi.org/10.1111/sms.70235
4. Breda SJ, Oei EHG, Zwerver J, Visser E, Waarsing E, Krestin GP, de Vos RJ. Effectiveness of progressive tendon-loading exercise therapy in patients with patellar tendinopathy: a randomised clinical trial. British Journal of Sports Medicine. 2021;55(9):501-509. https://doi.org/10.1136/bjsports-2020-103403
5. Rio E, Kidgell D, Purdam C, Gaida J, Moseley GL, Pearce AJ, Cook J. Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy. British Journal of Sports Medicine. 2015;49(19):1277-1283. https://doi.org/10.1136/bjsports-2014-094386
6. Xiao L, Zhou H, He J, Liu H, Li Y, Liu Z, Hu H. Comprehensive assessment of heavy slow resistance training and high-dose therapeutic ultrasound in managing patellar tendinopathy, a randomized single-blind controlled trial. BMC Sports Science, Medicine and Rehabilitation. 2024;16(1):213. https://doi.org/10.1186/s13102-024-01004-2
7. van der Vlist AC, Winters M, Weir A, Ardern CL, Welton NJ, Caldwell DM, Verhaar JAN, de Vos RJ. Which treatment is most effective for patients with Achilles tendinopathy? A living systematic review with network meta-analysis of 29 randomised controlled trials. British Journal of Sports Medicine. 2021;55(5):249-256. https://doi.org/10.1136/bjsports-2019-101872
8. Judd A, Wild K, Puxley L, Barker-Davies R. UK Defence Rehabilitation consensus agreement for the conservative management of Achilles and patellar tendinopathy: a modified Delphi approach. BMJ Military Health. 2026;172(2):172-177. https://doi.org/10.1136/military-2024-002893

Written and checked by the PocketPhysio editorial team. Last updated 2026-10-26.