Biomaterial Database

Muscle fiber composition and respiratory capacity in triathletes. 1987

M G Flynn, and D L Costill, and J P Kirwan, and W J Fink, and D R Dengel

Human Performance Laboratory, Ball State University, Muncie, IN.

In an effort to describe the skeletal muscle characteristics of trained triathletes, biopsies were obtained from the gastrocnemius, vastus lateralis, and posterior deltoid muscles of 11 triathletes and 4 normally active controls. Each specimen was analyzed for muscle fiber composition, respiratory capacity (QO2), and citrate synthase activity. The mean (+/- SE) percentage of type I fibers for the triathletes was 59 (4.0), 63 (3.3), and 60 (2.8) in the gastrocnemius, vastus lateralis, and deltoid, respectively (P greater than 0.05). The mean (+/- SE) QO2 values in the gastrocnemius (4.4 +/- 0.3 ml O2.min-1.g-1) and the vastus lateralis (4.1 +/- 0.2) were not significantly different while the QO2 values of the deltoid (3.6 +/- 0.2) were significantly lower than the gastrocnemius (P less than 0.05). The mean citrate synthase activity of the deltoid (27.7 +/- 1.7 mumol.min-1.g-1) was significantly lower than both the vastus lateralis (36.0 +/- 3.2) and the gastrocnemius (45.8 +/- 2.1) (P less than 0.05). There was a high correlation between the percentage of type I fibers and the citrate synthase activity within the vastus lateralis (r = .760) and deltoid (r = .610) (P less than 0.05) but not the gastrocnemius (r = .200). No significant relationships were observed between skeletal muscle characteristics and VO2 max nor between skeletal muscle characteristics and performance. The results of this study demonstrate that: (1) these triathletes have a high percentage of type I fibers in all three muscle groups; (2) skeletal muscle characteristics were not highly related to laboratory or competitive performance;(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D007866	Leg	The inferior part of the lower extremity between the KNEE and the ANKLE.	Legs
D008297	Male		Males
D009132	Muscles	Contractile tissue that produces movement in animals.	Muscle Tissue,Muscle,Muscle Tissues,Tissue, Muscle,Tissues, Muscle
D010101	Oxygen Consumption	The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)	Consumption, Oxygen,Consumptions, Oxygen,Oxygen Consumptions
D002950	Citrate (si)-Synthase	Enzyme that catalyzes the first step of the tricarboxylic acid cycle (CITRIC ACID CYCLE). It catalyzes the reaction of oxaloacetate and acetyl CoA to form citrate and coenzyme A. This enzyme was formerly listed as EC 4.1.3.7.	Citrate Synthase,Synthase, Citrate
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults
D001642	Bicycling	The use of a bicycle for transportation or recreation. It does not include the use of a bicycle in studying the body's response to physical exertion (BICYCLE ERGOMETRY TEST see EXERCISE TEST).
D012420	Running	An activity in which the body is propelled by moving the legs rapidly. Running is performed at a moderate to rapid pace and should be differentiated from JOGGING, which is performed at a much slower pace.	Runnings
D012782	Shoulder	Part of the body in humans and primates where the arms connect to the trunk. The shoulder has five joints; ACROMIOCLAVICULAR joint, CORACOCLAVICULAR joint, GLENOHUMERAL joint, scapulathoracic joint, and STERNOCLAVICULAR joint.	Shoulders