Three-Dimensional Take-off Step Kinetics of Long Jumpers with and without a Transtibial Amputation

Purpose The loads applied on the musculo-skeletal system during the long jump take-off step are not well established for non-amputee athletes or athletes with a lower extremity amputation. Information on joint loading and potential injury mechanisms is important for improving training or rehabilitation protocols, prosthetic design and the general understanding of the long jump. Methods Three-dimensional take-off step kinematics and kinetics were used for inverse dynamic model calculations on three male athletes with and seven male athletes without a below the knee amputation (BKA). Athletes with BKA used their affected leg as their take-off leg. Results Despite equivalent long jump performance, ground reaction force application characteristics were widely different and calculated joint loads were significantly lower in athletes with BKA compared to non-amputee athletes during the take-off step. The take-off step of the long jump for athletes with BKA seems to be dominated by sagittal plane movements, while for non-amputee athletes it involves sagittal plane movement and compensatory joint work in the frontal plane. Conclusions Coaches and athletes should adapt training protocols to the unique musculo-skeletal loading patterns of long jumpers with or without a BKA. Specifically, non-amputee athletes should strengthen the muscles responsible for hip and knee extension, as well as for frontal plane stabilization, early in the season to avoid injuries. The presented data enables clinicians to identify potential causes of pain or injury more differentially in both groups of athletes and might stimulate future research in the field of robotics and prosthetic components. Furthermore, the altered joint mechanics of athletes with BKA versus non-amputees serves as an explanation for their previously described more effective take-off step. Corresponding author: Johannes Funken, MSc, German Sport University Cologne, Institute of Biomechanics and Orthopaedics, Am Sportpark Müngersdorf 6, 50933 Cologne, Germany. Email: j.funken@dshs-koeln.de. Phone: +49(0)22149827662 Funding was provided by the Japan Broadcasting Cooperation (NHK). JF was funded by a graduate fellowship of the German Sport University Cologne. HH was funded by JSPS KAKENHI Grant Number 26702027. AMG's contribution to this project was also partially supported by the BADER Consortium, a US Department of Defense Congressionally Directed Medical Research Programs cooperative agreement (W81XWH-11-2-0222). None of the authors had any conflict of interest associated with the study. The results of the study are presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation. The results of the present study do not constitute endorsement by the American College of Sports Medicine. Accepted for publication November 2018. © 2018 American College of Sports Medicine

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