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G-40 Free Communication/Poster - Neuromuscular Control of Movement: JUNE 4, 2011 7: 30 AM - 11: 00 AM: ROOM: Hall B

Association of Gluteus Medius Activation with Leg Muscle Activation and Flexibility

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Board #150 June 4 8:00 AM - 9:30 AM

Goto, Shiho; Bell, David R.; Padua, Darin A.

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Medicine & Science in Sports & Exercise: May 2011 - Volume 43 - Issue 5 - p 923-924
doi: 10.1249/01.MSS.0000402579.19466.5c
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Gluteus medius (GMED) muscle activation influences hip movement during dynamic activities. Dysfunction of the GMED may contribute to excessive knee valgus position, which may contribute to anterior cruciate ligament injuries and patellofemoral pain syndrome. Clinical theory suggests that over-activation or decreased flexibility of leg muscles may facilitate alterations in GMED activity, thus indirectly affecting knee valgus position. However, research has not investigated these potential relationships.

PURPOSE: To determine the relationship between GMED activation and leg muscle activation amplitude and active range of motion (ROM).

METHODS: Thirty-seven healthy subjects (Males=8, Females=29) participated in this study (Ht: 167.0± 8.5cm, Mass: 65.4 ± 11.8kg, Age: 20.8± 2.1yo). Active ROM was assessed in the directions of hip abduction (HAB) and ankle dorsiflexion with the knee flexed (DF). Surface EMG were collected during the descent phase of a double leg squat task from the GMED, hip adductors (HAD), medial gastrocnemius (MG), lateral gastrocnemius (LG), and tibialis anterior (TA). All measurements were taken from the dominant leg defined as the leg used to kick a ball for maximal distance. GMED activity was the criterion variable and the predictor variables included HAD, MG, LG, and TA activation amplitude, as well as, HAB and DF ROM values. Separate Pearson correlation coefficients were computed between the criterion and each predictor variable (< 0.05).

RESULTS: GMED activation was negatively correlated with TA activation (r=-0.44, p=0.01). There were no significant correlations between GMED activation with HAD ROM (r=-0.01, p=0.95), DF ROM (r=0.31, p=0.08), ADD activation (r=-0.12, p=0.51), MG activation (r=-0.05, p=0.78), or LG activation (r=0.14, p=0.47).

CONCLUSION: Decreased GMED activation was associated with increased TA activation; however, other relationships were not significant. TA activation appears to be a factor related to GMED activity and should be considered when attempting to design injury prevention program to facilitate GMED function. This study was supported by the National Academy of Sports Medicine.

© 2011 American College of Sports Medicine