Resisted Sled Sprint Kinematics: The Acute Effect of Load and Sporting Population.

Katja M Osterwald,Ciarán Ó Catháin,David T Kelly,Thomas M Comyns

doi:10.3390/sports9100137

Katja M Osterwald, Ciarán Ó Catháin + Show 2 more

Open Access

https://doi.org/10.3390/sports9100137

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Journal: Sports	Publication Date: Sep 30, 2021
Citations: 4	License type: CC BY 4.0

Affiliation: Athlone Institute of Technology, University of Limerick

Abstract

In this study, we assessed the acute kinematic effects of different sled load conditions (unloaded and at 10%, 20%, 30% decrement from maximum velocity (Vdec)) in different sporting populations. It is well-known that an athlete’s kinematics change with increasing sled load. However, to our knowledge, the relationship between the different loads in resisted sled sprinting (RSS) and kinematic characteristics is unknown. Thirty-three athletes (sprinters n = 10; team sport athletes n = 23) performed a familiarization session (day 1), and 12 sprints at different loads (day 2) over a distance of 40 m. Sprint time and average velocity were measured. Sagittal-plane high-speed video data was recorded for early acceleration and maximum velocity phase and joint angles computed. Loading introduced significant changes to hip, knee, ankle, and trunk angle for touch-down and toe-off for the acceleration and maximum velocity phase (p < 0.05). Knee, hip, and ankle angles became more flexed with increasing load for all groups and trunk lean increased linearly with increasing loading conditions. The results of this study provide coaches with important information that may influence how RSS is employed as a training tool to improve sprint performance for acceleration and maximal velocity running and that prescription may not change based on sporting population, as there were only minimal differences observed between groups. The trunk lean increase was related to the heavy loads and appeared to prevent athletes to reach mechanics that were truly reflective of maximum velocity sprinting. Lighter loads seem to be more adequate to not provoke changes in maxV kinematics. However, heavy loading extended the distance over which it is possible to train acceleration.

Highlights

Sprinting is a powerful action where the muscles of the lower limbs produce high amounts of vertical and horizontal net force with each step [1]
This study investigated the effect of resisted sled sprinting (RSS) on sprint kinematics under various loading conditions similar to previous research; the examination of multiple joint angles, across different phases of a sprint, the number of loads and the comparison on how these loads influence kinematics in sprint athletes and invasion team sports athletes is novel
This study indicated that both sprint and team sport athletes respond to RSS in a very similar manner

Summary

Introduction

Sprinting is a powerful action where the muscles of the lower limbs produce high amounts of vertical and horizontal net force with each step [1]. Resistance training is a way of improving muscular power [8,9,10,11] and exercises such as squats, power cleans and deadlifts comprise the base of most strength and conditioning programs for athletes to develop speed and power These movements may reflect specificity from a physical development perspective, they lack movement similarity. Movements such as squats have been shown to have positive effects on sprint performance (2.3%); they appear to benefit actions such as vertical jumps that are more kinematically similar, to a greater extent (21%) [12]. With more recent literature demonstrating benefits of very heavy loads for acceleration and maximum velocity performance (50% and 60%Vdec) [39]

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