Effect of sex hormones on neuromuscular control patterns during landing.

Full Abstract

The purpose of the study was to investigate the effects of sex hormones across menstrual cycle phases on lower extremity neuromuscular control patterns during the landing phase of a drop jump. A repeated-measures design was utilized to examine sex hormone effects in 26 recreationally active eumenorrheic women. Varus/valgus knee angle and EMG activity from six lower extremity muscles were recorded during three drop jumps from a 50 cm platform in each phase of the menstrual cycle. Blood assays verified sex hormone levels and cycle phase. The semitendinosus muscle exhibited onset delays (p0.006) relative to ground contact during the luteal phase, and demonstrated a significant (p0.05) difference between early and late follicular phases. Muscle timing differences between the gluteus maximus and semitendinosus were decreased (p0.05) in the luteal compared to early follicular phases. These results suggest a different co-contractive behavior between the gluteus maximus and semitendinosus, signifying a shift in neuromuscular control patterns. It appears that female recreational athletes utilize a different neuromuscular control pattern for performing a drop jump sequence when estrogen levels are high (luteal phase) compared to when they are low (early follicular phase).

Author information

Author/s: Dedrick, Gregory S (GS); Sizer, Phillip S (PS); Merkle, Jennifer N (JN); Hounshell, Troy R (TR); Robert-McComb, Jacalyn J (JJ); Sawyer, Steven F (SF); Brismée, Jean-Michel (JM); Roger James, C (C);

Affiliation: Department of Rehabilitation Sciences, Texas Tech University Health Sciences Center, Doctor of Science in Physical Therapy Program, Center for Clinical Rehabilitation Research, Lubbock, TX 79430-6226, USA. gregory.dedrick(-atsign-)ttuhsc.edu

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology (J Electromyogr Kinesiol), published in England. (Language: eng)

Reference: 2008-Feb; vol 18 (issue 1) : pp 68-78

Dates: Created 2008/01/15; Completed 2008/05/16;

PMID: 17079166, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

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