TY - JOUR
T1 - Inspiratory muscles experience fatigue faster than the calf muscles during treadmill marching
AU - Perlovitch, Renana
AU - Gefen, Amit
AU - Elad, David
AU - Ratnovsky, Anat
AU - Kramer, Mordechai R.
AU - Halpern, Pinchas
N1 - Funding Information:
We appreciate the help of Dr. Uri Zaretsky (Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University) in installing the measurement system. This study was supported by a research grant from the Medical Corps of the Israeli Defense Forces (AG, DE, MRK, PH).
PY - 2007/4/15
Y1 - 2007/4/15
N2 - The possibility that respiratory muscles may fatigue during extreme physical activity and thereby become a limiting factor leading to exhaustion is debated in the literature. The aim of this study was to determine whether treadmill marching exercise induces respiratory muscle fatigue, and to compare the extent and rate of respiratory muscle fatigue to those of the calf musculature. To identify muscle fatigue, surface electromyographic (EMG) signals of the inspiratory (sternomastoid, external intercostals), expiratory (rectus abdominis and external oblique) and calf (gastrocnemius lateralis) muscles were measured during a treadmill march of 2 km at a constant velocity of 8 km/h. The extent of fatigue was assessed by determining the increase in root-mean-square (RMS) of EMG over time, and the rate of fatigue was assessed from the slope of the EMG RMS versus time curve. Results indicated that (i) the inspiratory and calf muscles are the ones experiencing the most dominant fatigue during treadmill marching, (ii) the rate of fatigue of each muscle group was monotonic between the initial and terminal phases of exercise, and (iii) the inspiratory muscles fatigue significantly faster than the calf at the terminal phase of exercise, and are likely to fatigue faster during the initial exercise as well. Accordingly, this study supports the hypothesis that fatigue of the inspiratory muscles may be a limiting factor during exercise.
AB - The possibility that respiratory muscles may fatigue during extreme physical activity and thereby become a limiting factor leading to exhaustion is debated in the literature. The aim of this study was to determine whether treadmill marching exercise induces respiratory muscle fatigue, and to compare the extent and rate of respiratory muscle fatigue to those of the calf musculature. To identify muscle fatigue, surface electromyographic (EMG) signals of the inspiratory (sternomastoid, external intercostals), expiratory (rectus abdominis and external oblique) and calf (gastrocnemius lateralis) muscles were measured during a treadmill march of 2 km at a constant velocity of 8 km/h. The extent of fatigue was assessed by determining the increase in root-mean-square (RMS) of EMG over time, and the rate of fatigue was assessed from the slope of the EMG RMS versus time curve. Results indicated that (i) the inspiratory and calf muscles are the ones experiencing the most dominant fatigue during treadmill marching, (ii) the rate of fatigue of each muscle group was monotonic between the initial and terminal phases of exercise, and (iii) the inspiratory muscles fatigue significantly faster than the calf at the terminal phase of exercise, and are likely to fatigue faster during the initial exercise as well. Accordingly, this study supports the hypothesis that fatigue of the inspiratory muscles may be a limiting factor during exercise.
KW - EMG, Exhaustion
KW - Exercise
KW - Respiratory muscles
KW - Training
UR - http://www.scopus.com/inward/record.url?scp=33846884437&partnerID=8YFLogxK
U2 - 10.1016/j.resp.2006.08.005
DO - 10.1016/j.resp.2006.08.005
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AN - SCOPUS:33846884437
SN - 1569-9048
VL - 156
SP - 61
EP - 68
JO - Respiratory Physiology and Neurobiology
JF - Respiratory Physiology and Neurobiology
IS - 1
ER -