Research article summary (published 27 Feb 2007):

Effect of slow movement and stretch-shortening cycle on lower extremity muscle activity and joint moments during squat.

Full Abstract

AIM: The purpose of the present study was to compare activity patterns of 8 muscles that cross the ankle, knee and hip joints under different conditions of squatting. METHODS: Ten male athletes performed squats at 3 different speeds (slow, normal, quick). Variables such as net moment and power about the joint were calculated during the descending and ascending phases of each squat. Using surface electrodes placed over the 8 lower extremity muscles, %iEMG was calculated during the ascending phase of each squat. RESULTS: In the descending phase, activities of the following 7 muscles were significantly greater for the quick squat (QS) than the normal squat (NS) or slow squat (SS): erector spinae (ES), gluteus maximus (Gmax), gluteus medius (Gmed), rectus femoris (RF), biceps femoris (BF), adductor longus (AL), and vastus lateralis (VL). Median frequency (MDF) of the Gmax muscle was significantly lower for NS than QS, and activity of the BF was significantly lower for NS than QS or SS. Mean moment of the hip joint was significantly lower for SS than QS. In the ascending phase, activities of the following 7 muscles were significantly greater for QS and NS than SS: ES, Gmax, Gmed, RF, BF, AL, and VL. MDF of the Gmax muscle was significantly lower for NS than QS, and the activity of the BF was significantly lower for NS than QS or SS. Mean moment of the hip joint was significantly higher for QS than SS or NS. Mean moment of the knee was significantly lower for SS than NS or QS. CONCLUSIONS: For QS, a stretch-shortening cycle increased the load on the Gmax. Mean muscle activity was less for SS than NS, and MDF was greater for SS than NS. These results suggest that SS mobilizes type-2 muscle fibers, despite the slow movement involved and the low risk of injury.

Author information

Author/s: Manabe, Y (Y); Shimada, K (K); Ogata, M (M);

Affiliation: Ibaraki Prefectural University of Health Sciences, Ibaraki, Japan. manabe(-atsign-)ipu.ac.jp

Journal and publication information

Publication Type: Journal Article

Journal: The Journal of sports medicine and physical fitness (J Sports Med Phys Fitness), published in Italy. (Language: eng)

Reference: 2007-Mar; vol 47 (issue 1) : pp 1-12

Dates: Created 2007/03/19; Completed 2007/06/13;

PMID: 17369791, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Adult Analysis of Variance Ankle Joint - physiology Electromyography Hip Joint - physiology Humans

Humans Knee Joint - physiology Lower Extremity - physiology Male Movement - physiology Muscle, Skeletal - physiology

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