Can measures of muscle–tendon interaction improve our understanding of the superiority of Kenyan endurance runners?

Purpose Leg muscle activation profiles and muscle–tendon interaction were studied with eleven internationally high-level Kenyan and eleven national level Japanese distance runners. Methods Ultrasonography and kinematics were applied together with surface electromyography (EMG) recordings of leg muscles when subjects ran on treadmill at 9.0 (SLOW) and 13.9 km h −1 (MEDIUM). Results At each speed, both groups presented similar contact and flight times. The kinematic and ultrasound analyses revealed that, in contrast to the Japanese runners, the Kenyans demonstrated during contact smaller stretching and shortening amplitudes ( p