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Knee muscular response strategies differ by developmental level but not gender during jump landing.
Electromyogr Clin Neurophysiol. 2004 Sep; 44(6):339-48.EC

Abstract

The purpose of this investigation was to determine differences between pre- and post-pubescent males and females in quadriceps (vastus medialis; VM) and hamstrings (medial hamstrings and biceps femoris; HAMS) muscular activation patterns via the root mean square of surface electromyography (SEMG) during self-initiated vertical jump landing. Fifty-eight subjects, divided into age and gender groupings, were compared on kinematic variables during pre-landing (100 msec preceeding initial ground contact), post-landing (100 msec following initial ground contact), and initial-contact-to-maximum-knee-flexion stages. Kinematic variables investigated were (1) SEMG values during each stage of the vertical-jump landing; (2) Co-contraction ratios (CCR), which represented the ratio of normalized hamstrings' activity to normalized quadriceps' activity; and, (3) knee angle at initial contact. Results indicated (1) no significant gender differences in variables measured; and, (2) significant developmental level differences. Post-pubescent subjects displayed greater HAMS acitivity and CCR values in the pre-landing stage relative to post-landing stages, indicating that post-pubescent subjects had a greater level of hamstrings co-contraction prior to landing than pre-pubescent subjects. Conversely, pre-pubescent subjects displayed greater post-landing and initial-contact-to-maximum-knee-flexion ratios, indicating a greater level of hamstrings' co-contraction during post-landing stages than post-pubescent subjects. There were no significant differences in knee angle at initial contact. The greater level of hamstrings' co-activation prior to landing by post-pubescent subjects indicated that they used a strategy of pre-tuning the hamstrings prior to landing (more CNS pre-activation) to control the ground reaction forces and anterior tibial displacement experienced by the knee during landing. On the other hand, pre-pubescent subjects controlled these forces by having a greater level of hamstrings' co-activation during landing, which represents more of a reflexive activation in response to ground impact.

Authors+Show Affiliations

University of New Hampshire's Applied Biomechanics and Motor Control Laboratory, Department of Kinesiology, Durham, NH 03824, USA. rvc@cisunix.unh.eduNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15473345

Citation

Croce, R V., et al. "Knee Muscular Response Strategies Differ By Developmental Level but Not Gender During Jump Landing." Electromyography and Clinical Neurophysiology, vol. 44, no. 6, 2004, pp. 339-48.
Croce RV, Russell PJ, Swartz EE, et al. Knee muscular response strategies differ by developmental level but not gender during jump landing. Electromyogr Clin Neurophysiol. 2004;44(6):339-48.
Croce, R. V., Russell, P. J., Swartz, E. E., & Decoster, L. C. (2004). Knee muscular response strategies differ by developmental level but not gender during jump landing. Electromyography and Clinical Neurophysiology, 44(6), 339-48.
Croce RV, et al. Knee Muscular Response Strategies Differ By Developmental Level but Not Gender During Jump Landing. Electromyogr Clin Neurophysiol. 2004;44(6):339-48. PubMed PMID: 15473345.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Knee muscular response strategies differ by developmental level but not gender during jump landing. AU - Croce,R V, AU - Russell,P J, AU - Swartz,E E, AU - Decoster,L C, PY - 2004/10/12/pubmed PY - 2004/11/9/medline PY - 2004/10/12/entrez SP - 339 EP - 48 JF - Electromyography and clinical neurophysiology JO - Electromyogr Clin Neurophysiol VL - 44 IS - 6 N2 - The purpose of this investigation was to determine differences between pre- and post-pubescent males and females in quadriceps (vastus medialis; VM) and hamstrings (medial hamstrings and biceps femoris; HAMS) muscular activation patterns via the root mean square of surface electromyography (SEMG) during self-initiated vertical jump landing. Fifty-eight subjects, divided into age and gender groupings, were compared on kinematic variables during pre-landing (100 msec preceeding initial ground contact), post-landing (100 msec following initial ground contact), and initial-contact-to-maximum-knee-flexion stages. Kinematic variables investigated were (1) SEMG values during each stage of the vertical-jump landing; (2) Co-contraction ratios (CCR), which represented the ratio of normalized hamstrings' activity to normalized quadriceps' activity; and, (3) knee angle at initial contact. Results indicated (1) no significant gender differences in variables measured; and, (2) significant developmental level differences. Post-pubescent subjects displayed greater HAMS acitivity and CCR values in the pre-landing stage relative to post-landing stages, indicating that post-pubescent subjects had a greater level of hamstrings co-contraction prior to landing than pre-pubescent subjects. Conversely, pre-pubescent subjects displayed greater post-landing and initial-contact-to-maximum-knee-flexion ratios, indicating a greater level of hamstrings' co-contraction during post-landing stages than post-pubescent subjects. There were no significant differences in knee angle at initial contact. The greater level of hamstrings' co-activation prior to landing by post-pubescent subjects indicated that they used a strategy of pre-tuning the hamstrings prior to landing (more CNS pre-activation) to control the ground reaction forces and anterior tibial displacement experienced by the knee during landing. On the other hand, pre-pubescent subjects controlled these forces by having a greater level of hamstrings' co-activation during landing, which represents more of a reflexive activation in response to ground impact. SN - 0301-150X UR - https://www.unboundmedicine.com/medline/citation/15473345/Knee_muscular_response_strategies_differ_by_developmental_level_but_not_gender_during_jump_landing_ DB - PRIME DP - Unbound Medicine ER -