Enhancement of Muscle Shortening Torque Preloaded with Muscle Lengthening is Joint-Specific
(Marzouq K. Almutairi, Gary R. Hunter, Donald H. Lein, SoJung Kim, David R. Bryan, Mario Inacio, Christopher P. Hurt, William Reed, Harshvardhan Singh)

Our cross-sectional study aimed to investigate joint specificity of concentric muscle torque enhancement after a maximum eccentric contraction for the knee versus ankle joints across two different movement velocities (120°/s and 180°/s). After a familiarization session, 22 healthy young adults randomly performed concentric (CONC) and maximum eccentric preloaded concentric (EccCONC) muscle strength tests of the knee extensors and ankle plantar flexors of the non-dominant leg on an isokinetic strength testing device. We calculated the ratio between EccCONC and CONC (EccCONC/CONC) for all the conditions as the marker of concentric muscle torque enhancement. Separate two-way (joints x velocity) within repeated measures ANOVAs were used to determine joint-specific torque differences at 120°/s and 180°/s. CONC and EccCONC were greater for the knee extensors versus ankle plantar flexors at 120°/s and 180°/s (32.86%–102%; p < 0.001 for both); however, EccCONC/CONC was greater for the ankle plantar flexors than knee extensors at 120°/s (52.4%; p < 0.001) and 180°/s (41.9%; p < 0.001). There was a trend of greater EccCONC/CONC for the knee extensors at 180°/s than 120°/s (6.6%; p = 0.07). Our results show that greater concentric muscle torque enhancement after a maximal eccentric contraction occurs for the ankle plantar flexors versus knee extensors. Whether the joint- specificity of concentric muscle torque enhancement after a maximal eccentric contraction differentially affects sports performance is unknown. Our data provide a reference framework to investigate joint-specific concentric muscle torque enhancement for general and clinical athletic populations.

Almutairi, M. K., Hunter, G. R., Lein, D. H., Kim, S., Bryan, D. R., Inacio, M. … Singh, H. (2023). Enhancement of Muscle Shortening Torque Preloaded with Muscle Lengthening is Joint-Specific. Journal of Human Kinetics, 87, 11-21. https://doi.org/10.5114/jhk/161729

Almutairi, M. K., Hunter, G. R., Lein, D. H., Kim, S., Bryan, D. R., Inacio, M., Hurt, C. P., Reed, W., and Singh, H. (2023). Enhancement of Muscle Shortening Torque Preloaded with Muscle Lengthening is Joint-Specific. Journal of Human Kinetics, 87, pp.11-21. https://doi.org/10.5114/jhk/161729

Almutairi, Marzouq et al. “Enhancement of Muscle Shortening Torque Preloaded with Muscle Lengthening is Joint-Specific.” Journal of Human Kinetics, vol. 87, 2023, pp. 11-21. doi:10.5114/jhk/161729.

Almutairi MK, Hunter GR, Lein DH, Kim S, Bryan DR, Inacio M et al. Enhancement of Muscle Shortening Torque Preloaded with Muscle Lengthening is Joint-Specific. Journal of Human Kinetics. 2023;87:11-21. https://doi.org/10.5114/jhk/161729