Exertional Costs of Changes in Directional Modes of Running

The energy expended and perceived exertion were determined for 9 soccer players while running forwards, backwards, and sideways at three treadmill speeds. The unorthodox modes of motion produced energy expenditure levels and subjective reactions similar to each other but significantly greater than running forwards. The added exertional costs of running backwards and sideways increased disproportionately at the higher speeds.