Two Ways to Load a Sore Achilles Tendon: Slow Heavy Strength Work vs. Eccentric Heel Drops

Achilles tendinopathy is a stubborn, aching problem in the tendon that connects your calf muscles to your heel. It is common in runners and jumping athletes, but it also affects active adults who simply spend a lot of time on their feet. For years, the standard rehab was the 'eccentric' heel-drop program: slowly lowering the heel off a step, many repetitions a day, most days of the week.

This Danish randomized controlled trial asked whether there is another valid path. Researchers took adults who had midportion Achilles pain for more than three months and randomly assigned them to one of two 12-week programs: the traditional eccentric heel-drop routine, or 'heavy slow resistance' training, which uses heavier weights, slower movement, and only a few gym sessions per week.

Both groups improved substantially, and the gains held up at follow-up a year later. On the main pain and function measures, the two programs were essentially equal. The heavy slow resistance group did report somewhat greater satisfaction in the early phase of treatment, and their program involved fewer total training sessions, which some people find easier to fit into real life.

For patients and parents, the practical message is encouraging: a painful Achilles tendon usually does not need rest alone, injections, or surgery as a first step. It needs a structured, progressively challenging loading program carried out consistently for roughly three months. Which specific program you use can be tailored to your schedule, equipment, and preferences, and that choice is best made with a physiotherapist or other qualified clinician who can adjust the load as your tendon adapts. Discomfort during rehab is common and expected within limits your clinician will set with you.

Key findings

• Researchers randomly assigned adults with midportion Achilles tendinopathy lasting more than three months to 12 weeks of either eccentric heel-drop training or heavy slow resistance training.
• Both programs produced meaningful and lasting improvements in pain and function, with no clear winner on the main outcomes.
• Patient satisfaction tended to be higher in the heavy slow resistance group in the early weeks of the program.
• Heavy slow resistance required fewer training sessions per week, which may make it easier for some people to stick with.
• The takeaway is not that one exercise is magic, but that progressively loading the tendon over about 12 weeks is what drives recovery.

Clinical relevance

This study underpins how modern clinics run tendon rehab on the gym floor: supervised, progressive loading with real weights, adapted to each patient's schedule, rather than rest or a single rigid protocol.

Prepared by the Volt Health team as an educational summary of the cited publication. It is not medical advice; assessment and treatment decisions should always be made with a qualified health professional.