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Quadriceps activation and perceived exertion during a high intensity, steady state contraction to failure
Author(s) -
Pincivero Danny M.,
Gear William S.
Publication year - 2000
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/(sici)1097-4598(200004)23:4<514::aid-mus9>3.0.co;2-4
Subject(s) - isometric exercise , exertion , perceived exertion , contraction (grammar) , motor unit , muscle contraction , motor unit recruitment , physical medicine and rehabilitation , medicine , physical therapy , electromyography , cardiology , anatomy , heart rate , blood pressure
The ability to sustain a high‐intensity, steady‐state muscle contraction may have differential effects on neuromuscular activation and perceived exertion. The purpose of this study was to examine changes in neuromuscular activation and perceived exertion at a near‐maximal steady‐state contraction of the quadriceps in healthy men. Seventeen healthy, college‐aged male volunteers were studied during isometric contractions equivalent to 80% of the maximum voluntary contraction (MVC). Perceived exertion was measured with a modified category‐ratio scale (CR‐10). The CR‐10 scale was anchored with one high anchor at 100% MVC and one low anchor at 10% MVC. Subjects then performed an 80% MVC for as long as they could sustain it. Subjects were asked to rate the feelings in their quadriceps every 5 s during the contraction. The results demonstrated significant increases in neuromuscular activation of the vastus medialis and vastus lateralis muscles ( P < 0.05) during the 80% MVC, but there were no significant muscle by time interactions. The results also demonstrated a significant increase ( P < 0.05) in perceived exertion during the 80% MVC. Neuromuscular activation of both muscles, and perceived exertion, were found to increase in linear ( P < 0.05) and quadratic ( P < 0.05) trends. Alterations in motor unit discharge properties or impairments in muscle fiber membrane excitability may account for nonlinear increases in vastii muscle activation and perceived exertion. © 2000 John Wiley & Sons, Inc. Muscle Nerve 23: 514–520, 2000.