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A novel stimulation pattern improves performance during repetitive dynamic contractions
Author(s) -
Kebaetse Maikutlo B.,
Lee Samuel C. K.,
BinderMacleod Stuart A.
Publication year - 2001
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/mus.1065
Subject(s) - isometric exercise , stimulation , functional electrical stimulation , quadriceps muscle , quadriceps femoris muscle , muscle contraction , contraction (grammar) , electromyography , medicine , physics , cardiology , physical medicine and rehabilitation
Abstract The purpose of this study was to determine the effect of three different stimulation patterns on repetitive knee movements. Each subject's quadriceps femoris was stimulated with: (1) a constant‐frequency train (CFT) with an interpulse interval (IPI) of 50 ms; (2) a variable‐frequency train (VFT)—similar to the CFT, except with an initial doublet with an IPI of 5 ms; and (3) a doublet‐frequency train (DFT) with multiple doublets (doublet IPI 5 ms) separated by 50 ms, while the muscle was resisted by a load equal to 10% of the muscle's maximum voluntary isometric contraction. The muscle was stimulated while the knee moved through a 50° arc of motion (90° to 40° of flexion). Testing was stopped when the subject failed to reach the target three consecutive times. Results showed that DFTs reached the target (mean ± SD) 36.4 ± 14.4 times, followed by VFTs (25.4 ± 17.9) and CFTs (17.4 ± 11.9). The DFT was the best pattern for producing shortening contractions. The results suggest that DFTs may have significant benefits during clinical functional electrical stimulation. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 744–752, 2001