title: Quantitative measurement of muscle fiber composition in a normal population.
abstract: To obtain normative muscle morphology data on a healthy population recruited from a population survey, we examined vastus lateralis biopsies from 58 men and 33 women, aged 26-67 years. Biopsies were measured with automated, computer-aided techniques. Data were analyzed according to gender and age, and the influence of blood pressure, body mass index (BMI), and smoking habits was also examined. Men had larger muscle fibers (fiber area approximately 5400 microm(2)) than women ( approximately 4000 microm(2), P = 0.003). No gender differences were seen in fiber composition, fiber roundness, percentage of connective tissue, or capillary density. Blood pressure did not influence fiber size or composition, but was correlated with fiber roundness in men. BMI was associated with fiber area in men, but not in women. Variations in age, smoking habits, and physical activity did not influence muscle morphology data substantially. Thus, in a normal population, men have larger muscle fibers than women, but similar fiber composition. Variation in gender, BMI, blood pressure, and physical activity may influence morphological features to a minor degree.
authors.affiliation: Department of Internal Medicine, University Hospital of Northern Norway, Breivika, N-9038 Tromsø, Norway.ingrid.toft@unn.no
authors.forename: Ingrid
authors.initials: I
authors.lastname: Toft
authors.forename: Sigurd
authors.initials: S
authors.lastname: Lindal
authors.forename: Kaare H
authors.initials: KH
authors.lastname: Bønaa
authors.forename: Trond
authors.initials: T
authors.lastname: Jenssen
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001706:Biopsy; D001794:Blood Pressure / Q000502:physiology; D015992:Body Mass Index; D002452:Cell Count; D015444:Exercise / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018485:Muscle Fibers, Skeletal / Q000502:physiology*; D018482:Muscle, Skeletal / Q000166:cytology*; D011153:Population; D012016:Reference Values; D012737:Sex Factors; D012907:Smoking / Q000473:pathology