Abstract
In this study, the functional role of starting blocks in the sprint start was examined. Participants were 6 sprinters (height: 175.8±5.0 cm; weight: 69.2±4.0 kg; personal best 100 m time: 10.65±0.13 s) who performed two kinds of sprint starts: a crouch start with starting blocks (BS), and a crouch start without starting blocks (CS). During block clearance, two force plates were used to measure the force applied to the front and rear starting blocks (in BS) or to the ground (in CS). The force plates were placed under each block (in BS) or under the participant's feet (in CS). The ground reaction force of the first and second step after block clearance was measured using another two force plates. The sampling frequency for these measurements was 1 kHz, and kinematic data were recorded using four high-speed cameras at 250 frames/s. The horizontal impulse applied to the rear block in BS was greater than that applied by the rear foot in CS; the horizontal impulse applied to both starting blocks in BS was greater than the horizontal impulse in CS. The vertical impulse applied to both starting blocks in BS was lower than the vertical impulse in CS, and the duration of force application to both starting blocks in BS was shorter than the duration of force application in CS. Taken together, starting blocks enable a greater horizontal impulse to be applied in a shorter time during block clearance, compared with no starting blocks. Therefore, the starting block can be regarded as an essential tool for enhancing sprint start performance.
