Bone mass in the calcaneus after heavy loaded eccentric calf-muscle training in recreational athletes with chronic Achilles tendinosis

In an ongoing prospective study of 14 recreational athletes (12 males and 2 females, mean age 44.2 +/- 7.1 years) with unilateral chronic Achilles ten dinosis, Lye investigated the effect of treatment with heavy-loaded eccentr ic calf-muscle training. Pain during activity (recorded on a VAS scale) and isokinetic concentric and eccentric calf-muscle strength (peak torque at 9 0 degrees/second and 225 degrees/second) on the injured and noninjured side were evaluated. In this group of patients, we examined areal bone mineral density (BMD) of the calcaneus after 9 months (range 6-14 months) of traini ng. BMD of the injured side (subjected to heavy-loaded eccentric training) was compared with BMD of the noninjured side. Before onset of heavy-loaded eccentric training, all patients had Achilles tendon pain which prohibited running activity, and significantly lower concentric and eccentric plantar flexion peak torque on the injured compared with the noninjured side. The t raining program consisted of 12 weeks of daily, heavy-loaded, eccentric cal f-muscle training; thereafter the training was continued for 2-3 days/week. The clinical results were excellent-all 14 patients were back at their pre injury level with full running activity at the 3 month follow-up. The conce ntric and eccentric plantar flexion peak torque had increased significantly and did not significantly differ from the noninjured side at the 3 and 9 m onth follow-up. There were no significant side-to-side differences in BMD o f the calcaneus. There was no significant relationship between BMD of the c alcaneus and calf-muscle strength. As a comparison group, we used 10 recrea tional athletes (5 males and 5 females) mean age 40.9 years (range 26-55 ye ars), who were selected for surgical treatment of chronic Achilles tendinos is localized at the 2-6 cm level. Their duration of symptoms and severity o f disease were the same as in the experimental group. There were no signifi cant side-to-side differences in BMD of the calcaneus preoperatively, but 1 2 months postoperatively BMD of the calcaneus was 16.4% lower at the injure d side compared with the noninjured side. Heavy-loaded eccentric calf-muscl e training resulted in a fast recovery in all patients, equaled the side-to -side differences in muscle strength, and was not associated with side-to-s ide differences in BMD of the calcaneus. In this group of middle-aged recre ational athletes, BMD of the calcaneus was not related to calf-muscle stren gth.