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Gait Posture. 2014;40(1):94-100. doi: 10.1016/j.gaitpost.2014.02.016. Epub 2014 Mar 10.

Comparison of quasi-static and dynamic squats: a three-dimensional kinematic, kinetic and electromyographic study of the lower limbs.

Author information

1
École de technologie supérieure (ÉTS), Montréal, QC, Canada; Laboratoire de recherche en Imagerie et Orthopédie, Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Hôpital Notre-Dame, Montréal, QC, Canada. Electronic address: clement.julien.24@gmail.com.
2
École de technologie supérieure (ÉTS), Montréal, QC, Canada; Laboratoire de recherche en Imagerie et Orthopédie, Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Hôpital Notre-Dame, Montréal, QC, Canada. Electronic address: nicola.hagemeister@etsmtl.ca.
3
École de technologie supérieure (ÉTS), Montréal, QC, Canada; Laboratoire de recherche en Imagerie et Orthopédie, Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Hôpital Notre-Dame, Montréal, QC, Canada. Electronic address: rachid.aissaoui@etsmtl.ca.
4
École de technologie supérieure (ÉTS), Montréal, QC, Canada; Laboratoire de recherche en Imagerie et Orthopédie, Centre de recherche du Centre hospitalier de l'Université de Montréal (CRCHUM), Hôpital Notre-Dame, Montréal, QC, Canada. Electronic address: jacques.deguise@etsmtl.ca.

Abstract

Numerous studies have described 3D kinematics, 3D kinetics and electromyography (EMG) of the lower limbs during quasi-static or dynamic squatting activities. One study compared these two squatting conditions but only at low speed on healthy subjects, and provided no information on kinetics and EMG of the lower limbs. The purpose of the present study was to contrast simultaneous recordings of 3D kinematics, 3D kinetics and EMG of the lower limbs during quasi-stat ic and fast-dynamic squats in healthy and pathological subjects. Ten subjects were recruited: five healthy and five osteoarthritis subjects. A motion-capture system, force plate, and surface electrodes respectively recorded 3D kinematics, 3D kinetics and EMG of the lower limbs. Each subject performed a quasi-static squat and several fast-dynamic squats from 0° to 70° of knee flexion. The two squatting conditions were compared for positions where quasi-static and fast-dynamic knee flexion-extension angles were similar. Mean differences between quasi-static and fast-dynamic squats were 1.5° for rotations, 1.9 mm for translations, 2.1% of subjects' body weight for ground reaction forces, 6.6 Nm for torques, 11.2 mm for center of pressure, and 6.3% of maximum fast-dynamic electromyographic activities for EMG. Some significant differences (p<0.05) were found in internal rotation, anterior translation, vertical force and EMG. All differences between quasi-static and fast-dynamic squats were small. 69.5% of compared data were equivalent. In conclusion, this study showed that quasi-static and fast-dynamic squatting activities are comparable in terms of 3D kinematics, 3D kinetics and EMG, although some reservations still remain.

KEYWORDS:

Electromyography; Kinematics; Kinetics; Knee; Squatting

PMID:
24656716
DOI:
10.1016/j.gaitpost.2014.02.016
[Indexed for MEDLINE]

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