Contribution of segmental kinetic energy to forward propulsion of the centre of mass: Analysis of sprint acceleration

This study aimed to measure the contribution of each body segment to the production of total body kinetic energy (KE) during a 40-m sprint. Nine recreational sprinters performed two 40-m sprints wearing a MVN Biomech suit (Xsens). Data recorded were used to calculate total body KE, and the KE of each segment. The KE of each segment was then expressed as a percentage of the total body KE. We divided the sprint into three phases: 1 - start to maximal power (P-max), 2 - P-max to maximal velocity (V-max), and 3 - V-max to the end of the 40 m. Total body KE increased from the start to the end of the 40-m sprint (from 331.3 +/- 68.4 J in phase 1 to 2378.8 +/- 233.0 J in phase 3; p <= 0.001). The contribution of the head-trunk increased (from 39.5 +/- 2.4% to 46.3 +/- 1.1%; p <= 0.05). Contribution of the upper and lower limbs decreased over the three phases (respectively from 15.7 +/- 2.5% to 10.6 +/- 0.6% and from 44.8 +/- 2.1% to 43.1 +/- 1.5%; p <= 0.05). This study revealed the important contribution of the trunk to forward propulsion throughout the entire acceleration phase.