Energetics (and kinematics) of short shuttle runs.

Purposes: The energy cost of shuttle running (C netSR), over distances of 10–20 m, was reported to increase with the shuttle speed and to decrease with the shuttle distance. The aims of this study were to assess C netSR over a shorter distance (5 m), at different speeds, and to estimate the energy cost based on a simple kinematic analysis (C netK). Methods: Ten subjects (six basketball players, BP; four non-basketball players, NBP) performed ten shuttle runs (SR) with 30 s of passive recovery in-between, over a distance of 5 + 5 m (with a 180° change of direction); these experiments were repeated at different speeds (range 2–3.5 m s−1). The values of average (v mean) and maximal (v max) speed during each run were determined by means of kinematic analysis and C netK was calculated as: 0.96v2max. C netSR was calculated based on data of oxygen uptake, blood lactate concentration and distance covered. Results: The relationships between C (J m−1 kg−1) and v (m.s−1) are well described by C netK (all subjects) = 11.76v − 13.09, R 2 = 0.853; C netSR (BP) = 11.94v − 12.82, R 2 = 0.636; and C netSR (NBP) = 14.09v − 14.53, R 2 = 0.738. Hence C netSR ≈ C netK in BP, whereas C netSR > C netK in NBP (un-familiar with this specific motor task). Discussion: The calculations proposed in this study allow to estimate C of short SR based on simple measures of v max and can be utilized to develop training protocols in basketball as well as in other team sports (characterized by repeated sprints over short distances).