Thigh loaded wearable resistance increases sagittal plane rotational work of the thigh resulting in slower 50-m sprint times

ABSTRACT

This study determined the acute changes in rotational work with thigh attached wearable resistance (WR) of 2% body mass during 50-m sprint-running. Fourteen athletes completed sprints with, and without, WR in a randomised order. Sprint times were measured via timing gates at 10-m and 50-m. Rotational kinematics were obtained over three phases (steps 1–2, 3–6 and 7–10) via inertial measurement unit attached to the left thigh. Quantification of thigh angular displacement and peak thigh angular velocity was subsequently derived to measure rotational work. The WR condition was found to increase sprint times at 10-m (1.4%, effect size [ES] 0.38, p 0.06) and 50-m (1.9%, ES 0.55, p 0.04). The WR condition resulted in trivial to small increases in angular displacement of the thigh during all phases (0.6–3.4%, ES 0.04–0.26, p 0.09–0.91). A significant decrease in angular velocity of the thigh was found in all step phases (−2.5% to −8.0%, ES 0.17–0.51, p < 0.001–0.04), except extension in step phase 1 with the WR. Rotational work was increased (9.8–18.8%, ES 0.35–0.53, p < 0.001) with WR in all phases of the sprint. Thigh attached WR provides a means to significantly increase rotational work specific to sprinting.

KEYWORDS:

• Acceleration
• velocity
• kinematics
• external loading

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Disclosure statement

John 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.

Shelley Diewald held a part-time contract with Lila from 2019 April - 2020 January; responsible for disseminating research findings for the company and wider public. Shelley did not contribute to discussion writing of this research and refrained from drawing and reporting any conclusions surrounding the data.

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.

Additional information

Funding

Paul Macadam received funding from Sportboleh Sdh Bhd, Malaysia.