Acute changes in acceleration phase sprint biomechanics with lower body wearable resistance

ABSTRACT

The aim of this acute cross-sectional study was to quantify the kinematic and kinetic changes that occur during sprint acceleration when lower body WR is worn. Fifteen male rugby athletes (19 years; 181 cm; 91 kg) were assessed during maximal effort over−ground and treadmill sprinting over 20 m under three different loading conditions: 0%, 3% and 5% body mass (BM) added weight attached to the lower body. Treadmill data provided a convenient estimate of kinetic changes in the absence of in-ground force plates. The loaded conditions resulted in significantly increased ground contact time (5 to 6%) and decreased step frequency (−2 to −3%) during sprint accelerations (effect size = 0.32–0.72). Moderate WR loading (3% BM) resulted in increased (9%; effect size = 0.66) theoretical maximum horizontal force (relative to BM) and unchanged 20 m sprint times (p > 0.05). Heavier WR loading (5% BM) resulted in a significant decrease (−4%) in vertical ground reaction forces (relative to total system mass) and slower (1 to 2%) 20 m sprint times (effect size = 0.38–0.70). Lower body WR loading up to 5% BM can provide specific sprint training overload, while affecting sprint acceleration biomechanics by ≤ 6%.

KEYWORDS:

• Horizontal force
• velocity
• power
• kinematics
• kinetics
• training specificity

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Acknowledgments

The authors would like to acknowledge the subjects that volunteered for the study.

Additional information

Funding

This work was supported by the Sportboleh, Sdh Bhd.

Notes on contributors

Kim David Simperingham

Kim David Simperingham received funding from Sportboleh Sdh Bhd, a company that may be affected by the research reported in the enclosed paper. The company was not involved in the design, analysis or writing of the research article.

John B Cronin

John B Cronin is Head of Research for Lila but is blinded from data collection, statistical analyses and writing of article, and is typically involved in methodological design and final proofing.

Paul Macadam

Paul Macadam’s PhD was funded by Lila from March 2018 to March 2020, which therefore includes his involvement in the study design, data collection, statistical analyses, and writing of this article.