Training-Related Changes in Force-Power Profiles: Implications for the Skeleton Start.
Athletes’ force-power characteristics influence sled velocity during the skeleton start, which is a crucial determinant of performance. This study characterised force-power profile changes across an 18-month period and investigated the associations between these changes and start performance.
Seven elite- and five talent-squad skeleton athletes’ (representing 80% of registered athletes in the country) force-power profiles and dry-land push-track performances were assessed at multiple time-points over two 6-month training periods and one 5-month competition season. Force-power profiles were evaluated using an incremental leg-press test (Keiser A420) and 15-m sled velocity was recorded using photocells.
Across the initial maximum strength development phases, increases in maximum force (Fmax) and decreases in maximum velocity (Vmax) were typically observed. These changes were greater for talent (23.6 and -12.5%, respectively) compared with elite (6.1 and -7.6%, respectively) athletes. Conversely, decreases in Fmax (elite: -6.7%; talent: -10.3%) and increases in Vmax(elite: 8.1%; talent: 7.7%) were observed across the winter period, regardless of whether athletes were competing (elite) or accumulating sliding experience (talent). When the training emphasis shifted towards higher-velocity, sprint-based exercises in the second training season, force-power profiles seemed to become more velocity-oriented (higher Vmax and more negative force-velocity gradient) which was associated with greater improvements in sled velocity (r = 0.42 and -0.45, respectively).
These unique findings demonstrate the scope to influence force-power generating capabilities in well-trained skeleton athletes across different training phases. In order to enhance start performance, it seems important to place particular emphasis on increasing maximum muscle contraction velocity.
Autor / Fonte:Steffi L Colyer, Keith A Stokes, James L J Bilzon, Danny Holdcroft, Aki I T Salo International Journal of Sports Physiology and Performance 2017 September 5, : 1-26