Very-Heavy Sled Training for Improving Horizontal-Force Output in Soccer Players

TLDR

Sprint acceleration relies on generating large horizontal ground‑reaction forces and efficient force application, both of which are critical for team‑sport performance. The study examined whether very‑heavy sled sprint training (80 % body mass) enhances horizontal‑force production by improving mechanical effectiveness. Sixteen amateur soccer players completed an 8‑week protocol of 16 sessions of 10 × 20 m sled sprints, with performance and mechanical outputs assessed via velocity‑time field methods before and after training. The sled group showed larger increases in maximal horizontal force (effect size 0.80 vs 0.20) and mechanical effectiveness (0.95 vs –0.11) than controls, with moderate 5‑m and small 20‑m sprint gains, indicating that very‑heavy sled training can improve force production and sprint performance in team‑sport athletes.

Abstract

Background: Sprint running acceleration is a key feature of physical performance in team sports, and recent literature shows that the ability to generate large magnitudes of horizontal ground-reaction force and mechanical effectiveness of force application are paramount. The authors tested the hypothesis that very-heavy loaded sled sprint training would induce an improvement in horizontal-force production, via an increased effectiveness of application. Methods: Training-induced changes in sprint performance and mechanical outputs were computed using a field method based on velocity–time data, before and after an 8-wk protocol (16 sessions of 10- × 20-m sprints). Sixteen male amateur soccer players were assigned to either a very-heavy sled (80% body mass sled load) or a control group (unresisted sprints). Results: The main outcome of this pilot study is that very-heavy sled-resisted sprint training, using much greater loads than traditionally recommended, clearly increased maximal horizontal-force production compared with standard unloaded sprint training (effect size of 0.80 vs 0.20 for controls, unclear between-groups difference) and mechanical effectiveness (ie, more horizontally applied force; effect size of 0.95 vs –0.11, moderate between-groups difference). In addition, 5-m and 20-m sprint performance improvements were moderate and small for the very-heavy sled group and small and trivial for the control group, respectively. Practical Applications: This brief report highlights the usefulness of very-heavy sled (80% body mass) training, which may suggest value for practical improvement of mechanical effectiveness and maximal horizontal-force capabilities in soccer players and other team-sport athletes. Results: This study may encourage further research to confirm the usefulness of very-heavy sled in this context.