Contraction duration affects metabolic energy cost and fatigue in skeletal muscle.

Content Provider	Semantic Scholar
Author	Hogan, Michael C. Ingham, Erica Kurdak, Sanli Sadi
Copyright Year	1998
Abstract	It has been suggested that during a skeletal muscle contraction the metabolic energy cost at the onset may be greater than the energy cost related to holding steady-state force. The purpose of the present study was to investigate the effect of contraction duration on the metabolic energy cost and fatigue process in fully perfused contracting muscle in situ. Canine gastrocnemius muscle (n = 6) was isolated, and two contractile periods (3 min of isometric, tetanic contractions with 45-min rest between) were conducted by each muscle in a balanced order design. The two contractile periods had stimulation patterns that resulted in a 1:3 contraction-to-rest ratio, with the difference in the two contractile periods being in the duration of each contraction: short duration 0.25-s stimulation/0.75-s rest vs. long duration 1-s stimulation/3-s rest. These stimulation patterns resulted in the same total time of stimulation, number of stimulation pulses, and total time in contraction for each 3-min period. Muscle O2 uptake, the fall in developed force (fatigue), the O2 cost of developed force, and the estimated total energy cost (ATP utilization) of developed force were significantly greater (P < 0.05) with contractions of short duration. Lactate efflux from the working muscle and muscle lactate concentration were significantly greater with contractions of short duration, such that the calculated energy derived from glycolysis was three times greater in this condition. These results demonstrate that contraction duration can significantly affect both the aerobic and anaerobic metabolic energy cost and fatigue in contracting muscle. In addition, it is likely that the greater rate of fatigue with more rapid contractions was a result of elevated glycolytic production of lactic acid.
Starting Page	12
Ending Page	26
Page Count	15
File Format	PDF HTM / HTML
Alternate Webpage(s)	http://ajpendo.physiology.org/content/ajpendo/274/3/E397.full.pdf
Alternate Webpage(s)	http://ajpendo.physiology.org/content/ajpendo/274/3/e397.full.pdf
PubMed reference number	9530120v1
Volume Number	274
Issue Number	3
Part	1
Journal	The American journal of physiology
Language	English
Access Restriction	Open
Subject Keyword	Contract agreement Fatigue Glycolysis Lactic acid Metabolic Process, Cellular Muscle Contraction Myalgia Oxygen Skeletal muscle structure contraction skeletal muscle tetanic contractions
Content Type	Text
Resource Type	Article