BACKGROUND: Eccentric exercise has been shown to provide good short-term clinical results in the treatment of painful mid-portion chronic Achilles tendinopathies. However, the mechanisms behind the positive effects of eccentric rehabilitation regimes are not known, and research into the biomechanics of the exercise may improve our understanding.

METHODS: Sixteen healthy subjects performed one-legged full weight bearing ankle plantar and dorsiflexion exercises during which three-dimensional ground reaction forces (GRF), ankle joint kinematics and surface electromyography (EMG) of the lower leg muscles were recorded. Joint kinematics, GRF frequency contents, average EMG amplitudes, and Achilles tendon loads were calculated.

FINDINGS: The eccentric movement phase was characterized by a higher GRF frequency content in the 8-12 Hz range, and reduced EMG activity in the lower leg muscles. No differences in Achilles tendon loads were found.

INTERPRETATION: This descriptive study demonstrates differences in the movement biomechanics between the eccentric and concentric phases of one-legged full weight bearing ankle dorsal and plantar flexion exercises. In particular, the findings imply that although the tendon loads are similar, the tendon is vibrated at higher frequencies during the eccentric phase than during the concentric phases. This study provides data that may explain the mechanisms behind the effectiveness of eccentric exercises used in the treatment of Achilles tendinopathies.

PURPOSE: The purpose of this study was to investigate the effect of massage applied to the thigh muscles on joint repositioning error (JRE) in patients suffering from osteoarthritis (OA).We hypothesized that stimulating massage of the muscles around an osteoarthritic knee joint, could improve the neuromuscular function and thereby optimize the positive and minimize the negative performance factors in relation to an exercise program.

METHODS: In a cross-over design, 19 patients with knee osteoarthritis, mean age of 73.1 years (SD: 9.4; range 56 to 88 years), recruited from the local department of rheumatology, were randomly allocated to either receive massage and a week later, act as controls or vice versa. The applied massage consisted of stimulating massage of the quadriceps femoris, sartorious, gracilus, and hamstrings muscles for 10 min on the affected leg. Participants had their JRE measured before and immediately after the 10 min massage and control sessions. Data were analyzed by using paired t-test.

RESULTS: No significant change in JRE was observed (95% CI: -0.62 degrees to 0.85 degrees, p = 0.738).

CONCLUSION: Massage has no effect on the immediate joint repositioning error in patients with knee osteoarthritis, ie, if an improved JRE is important for improving the performance factors when exercising, stimulating massage may not be recommendable to use.