Immediate Effects of two Isometric Calf Muscle Exercises on Mid-portion Achilles Tendon Pain.

This pilot cross-over study looked at whether a single isometric calf-muscle hold could immediately change Achilles tendon pain during a functional loading test, and whether bending or straightening the knee mattered. Eleven people with mid-portion Achilles tendinopathy, recruited through NHS physiotherapy services and running clubs, performed an isometric plantarflexion exercise (calf raise hold) with the knee either fully extended or flexed to 80 degrees, then crossed over to the other position after at least a week. Pain during a specific loading test, rated on an 11-point scale, dropped by an average of 1.6 points with the knee extended and 1.3 points with the knee flexed, both statistically significant reductions, roughly a 50% decrease. There was no significant difference between the two knee positions, though a 20% larger reduction with the knee extended did not reach significance.

With only 11 participants and no long-term follow-up, these findings should be seen as preliminary and exploratory rather than confirmation of a lasting treatment effect.

If you have Achilles tendon pain from tendinopathy, you might wonder whether a simple calf exercise can ease your pain right away, and whether knee position matters. This small pilot study tested that idea with 11 people who had mid-portion Achilles tendon pain, recruited from NHS physiotherapy clinics and running clubs. Each person held an isometric calf raise (a static muscle contraction without movement) with their knee either straight or bent, then tried the other position on a different day.

Pain during a specific loading test dropped by about half immediately after either version of the exercise, a statistically significant change. There was no clear difference between straight-knee and bent-knee positions, though a slightly bigger drop with the knee straight did not reach statistical significance. Because only 11 people took part and the study only measured an immediate effect rather than following people over time, these results are best thought of as an early, exploratory finding.

They cannot tell us whether the pain relief lasts or whether this exercise changes the underlying tendon problem.

This is a summary of research, not medical advice. Talk to your own healthcare provider about anything affecting your care.

This randomised cross-over pilot trial examined the immediate analgesic effect of isometric plantarflexion holds on Achilles tendon pain during a functional loading task, comparing knee-extended versus knee-flexed positions in 11 participants with mid-portion Achilles tendinopathy recruited from NHS community physiotherapy and running clubs. Both positions produced statistically significant mean reductions in NPRS pain scores during the loading test (knee extension: 1.6 points, 95% CI 0.83-2.45, p=0.001; knee flexion: 1.3 points, 95% CI 0.31-2.19, p=0.015), approximating a 50% reduction. No significant between-position difference was detected, though a 20% larger reduction with knee extension approached but did not reach significance (p=0.110), a finding the authors describe as potentially clinically relevant but unconfirmed. Given the small sample size typical of pilot work, the single-session immediate-effect design, and absence of longer-term follow-up, these results should be interpreted as hypothesis-generating rather than evidence of sustained analgesic or therapeutic benefit.

The trial supports feasibility of this cross-over protocol and the tolerability of both exercise positions, but adequately powered trials with longer follow-up are needed before drawing conclusions about comparative effectiveness of knee position or durability of pain reduction.