Differences in spatio-temporal characteristics between land-based and ice-based bobsleigh push training

This study compared the spatio-temporal characteristics of bobsleigh pushing between land-based training and ice-based pushing conditions. Spatio‑temporal parameters were collected from active national team bobsleigh athletes during land‑based and ice‑based pushing across the start, acceleration, and high‑velocity phases using a markerless three‑dimensional motion capture system. Bayesian paired-samples t-tests were used to compare land-based and ice-based pushing within each position and phase. Spatiotemporal gait parameters tended toward higher step frequency and shorter stride duration, stance time, swing time, and flight time on ice, with differences most concentrated during the start phase across positions. Vertical COM position tended to be smaller on ice for both maximum and mean values at all three positions; significant differences were limited to maximum values in the pusher during start and acceleration and in the brakeman during start and high-velocity, and to mean values in the pilot during high-velocity, in the pusher during acceleration, and in the brakeman during start and acceleration. Horizontal mean and maximum velocities tended to be greater on ice. Mean acceleration was greater on ice for all positions and phases except the pilot during start and high-velocity, and maximum acceleration was greater on ice for the pilot and pusher during start and acceleration and for the brakeman during start. The ice surface may be one of the factors underlying changes in push technique; however, different pushing formats and individual loads may also simultaneously affect the spatio-temporal characteristics of pushing. Land‑based training for the start and acceleration phases may carry a risk of negative transfer to ice pushing, while high‑velocity phase training on land may fail to provide the sport‑specific stimulus required for ice pushing. Based on these findings, it is recommended that land‑based push training emphasise horizontal force application, moderately increase load to enhance step frequency and propulsive force, incorporate overspeed running and downhill push drills to strengthen neuromuscular control during the high‑velocity phase, and include additional lower‑limb eccentric and plyometric training.