Biomaterial Database

Effects of prior exercise on the performance of intense isometric exercise. 1988

R J Maughan

Department of Environmental and Occupational Medicine, University Medical School, Aberdeen.

The influence of a regimen designed to lower the muscle glycogen content on the capacity to perform a single brief isometric contraction has been studied. Eight male subjects performed a single exhausting isometric contraction of the knee extensor muscles at a tension corresponding to 60% of maximum voluntary contraction (MVC). This was followed by prolonged cycling exercise at a work rate equivalent to approximately 75% of maximum oxygen uptake in order to reduce the muscle glycogen content. A diet low in carbohydrate was consumed for the remainder of this day in order to retard the resynthesis of muscle glycogen. The isometric contraction at 60% of MVC was repeated on the following day. Endurance time on the first day was 53.8 +/- 8.4 s (mean +/- SD); this was reduced (45.8 +/- 12.1 s; p less than 0.02) on the second day. From previously published data on rates of muscle glycogen utilisation during isometric exercise, it seems probable that insufficient glycogen is available in the muscle under the low carbohydrate condition to enable maximum performance to be achieved.

UI	MeSH Term	Description	Entries
D007537	Isometric Contraction	Muscular contractions characterized by increase in tension without change in length.	Contraction, Isometric,Contractions, Isometric,Isometric Contractions
D007773	Lactates	Salts or esters of LACTIC ACID containing the general formula CH3CHOHCOOR.
D008297	Male		Males
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
D010807	Physical Endurance	The time span between the beginning of physical activity by an individual and the termination because of exhaustion.	Endurance, Physical,Physical Stamina,Stamina, Physical
D001835	Body Weight	The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.	Body Weights,Weight, Body,Weights, Body
D004040	Dietary Carbohydrates	Carbohydrates present in food comprising digestible sugars and starches and indigestible cellulose and other dietary fibers. The former are the major source of energy. The sugars are in beet and cane sugar, fruits, honey, sweet corn, corn syrup, milk and milk products, etc.; the starches are in cereal grains, legumes (FABACEAE), tubers, etc. (From Claudio & Lagua, Nutrition and Diet Therapy Dictionary, 3d ed, p32, p277)	Carbohydrates, Dietary,Carbohydrate, Dietary,Dietary Carbohydrate
D004734	Energy Metabolism	The chemical reactions involved in the production and utilization of various forms of energy in cells.	Bioenergetics,Energy Expenditure,Bioenergetic,Energy Expenditures,Energy Metabolisms,Expenditure, Energy,Expenditures, Energy,Metabolism, Energy,Metabolisms, Energy
D005082	Physical Exertion	Expenditure of energy during PHYSICAL ACTIVITY. Intensity of exertion may be measured by rate of OXYGEN CONSUMPTION; HEAT produced, or HEART RATE. Perceived exertion, a psychological measure of exertion, is included.	Physical Effort,Effort, Physical,Efforts, Physical,Exertion, Physical,Exertions, Physical,Physical Efforts,Physical Exertions