Body load in heel-strike running: the effect of a firm heel counter

The effect of a firm heel counter in the shoe was studied in 11 athletes during submaximal heel-strike running on a treadmill under standardized conditions. The runners were tested in identical shoes with and without the distal 2 cm of the firm heel counter. Body load was expressed by absolute and relative VO2, surface EMG on the right leg, and g-force registration from an accelerometer below the right tibial tuberosity. The heel counter caused a 2.4% significant decrease in VO2, a reduction in musculoskeletal transients, and a decrease in the activity of the triceps surae and quadriceps muscles at heel strike. The changes found are expressions of kinematic adaptations in the body to increased or decreased load and provide functional evidence for the loading factor in the pathophysiology of overuse injuries.