Recovery of calf muscle endurance 3 months after an Achilles tendon rupture.

The purpose of this study was to evaluate calf muscle endurance in a seated position 3 months after an Achilles tendon rupture and to evaluate how the ability to perform standardized seated heel-rises correlated to the single-leg standing heel-rise test and to patient-reported symptoms evaluated with the Achilles tendon Total Rupture Score (ATRS) 3 and 6 months after the injury. Ninety-three patients were included from a cohort of 101 patients participating in a prospective, randomized controlled trial comparing surgical and nonsurgical treatment after Achilles tendon rupture. Forty-seven patients were treated surgically and 46 nonsurgically. Ninety-one patients out of 93 (98%) could perform the standardized seated heel-rises. At the 3-month follow-up, there was a significant difference (P < 0.001) between the injured and the healthy side performing standardized seated heel-rises. There were also significant correlations (r = 0.29-0.37, P = < 0.05) between the standardized seated heel-rises and ATRS 3 and 6 months after injury in the group who could not perform single-leg standing heel-rises. There were no significant differences between the surgical and nonsurgical treatment groups. The evaluation of standardized seated heel-rises appears to be a useful tool to quantify progress and predict future functional performance and patient-reported symptoms.