Biomedical subjects
Edward M Winter
Publications and source records attributed to Edward M Winter.
Effects of creatine supplementation on cerebral white matter in competitive sportsmen.
OBJECTIVES: To determine the neurobiochemical sequelae of oral creatine monohydrate supplementation in active athletes. DESIGN/PARTICIPANTS: Eighteen sportsmen underwent single-voxel proton magnetic resonance spectroscopy of the deep frontal cerebral white matter before and after 5 days of oral ingestion: 12 of 18 swallowed 4 x 5 g creatine monohydrate per day, and the remaining swallowed a placebo. MAIN OUTCOME MEASUREMENTS: Creatine, choline, and N-acetyl spectral resonances were evaluated at both long (135 ms) and short (20 ms) echo times. RESULTS: A mixed-design factorial ANOVA demonstrated no interaction over time in any of the measures (P at least 0.081). CONCLUSIONS: The results suggest that, for the given dosage regimen, ingested creatine augmentation does not alter the magnetic resonance visible creatine pool in the deep frontal cerebral white matter of young active sportsmen.
Modeling maximum oxygen uptake of elite endurance athletes.
PURPOSE: To compare the maximum oxygen uptake V0(2max) of elite endurance athletes and to explain why the body mass exponent, necessary to render V0(2max) independent of body mass, appears to be greater than 0.67. METHODS: Study 1: V0(2max) of 174 international sportsmen and women was assessed. Athletes were recruited from seven sports (middle- and long-distance runners, heavyweight and lightweight rowers, triathletes, and squash and badminton players). Study 2: calf and thigh leg muscle masses were estimated in 106 male and 30 female athletes from 11 sports. Differences in V0(2max) and leg muscle masses between "sports" and "sex" were analyzed independent of body mass by using allometric log-linear ANCOVA. RESULTS: Heavyweight rowers had the greatest V0(2max) when expressed in L.min but long-distance runners had the highest V0(2max)in mL.kg.min. However, the ANCOVA identified no difference in "mass independent" V0(2max) between the five "pure" endurance sports (runners, rowers, and triathletes) (P > 0.05) with the two racket sports being significantly lower. The body mass covariate exponent was inflated, estimated as 0.94. The results from study 2 estimated calf and thigh leg muscle masses to increase in proportion to body mass, and, respectively. CONCLUSIONS: After having controlled for differences in body mass, V0(2max) did not differ between pure endurance sports (P > 0.05). Assuming that athletes' thigh muscle mass increases in proportion to body mass as observed in study 2, a similar disproportional increase in V0(2max) would be anticipated, providing a plausible explanation for the inflated mass exponent associated with V0(2max) identified in this and other studies.
Allometric scaling of strength in an independently living population age 55-86 years.
Most physiological functions vary allometrically with body size; however, few investigators have examined the relationship between strength and body size with allometric scaling. Thus, we hypothesized that allometric analysis would reveal that both the amount and quality of muscle are significant determinants of strength in the elderly. Allometric analyses were used to determine the influence of limb cross-sectional area (CSA), physical activity, demispan (distance between index-middle finger web and the sternal notch), leg length, and sex on grip and plantar flexor strength in men (n = 188) and women (n = 205) age 55-86 years. Physical activity was measured using a self-reporting questionnaire (Taylor et al. [1978] J Chron Dis 31:741-755). Forearm and leg CSA was estimated from anthropometry. There was an age-related decline in grip strength, independent of forearm CSA, demispan, and sex, equal to approximately 12% per decade, whereas plantar flexor strength adjusted for leg CSA, physical activity, and sex was reduced at a rate of approximately 15% per decade. The allometric models explained 71.4% (r = 0.845) and 38.8% (r = 0.623) of the variance in grip and plantar flexor strength, respectively. Model parameters were identified using multiple linear regression (P < 0.05). Thus, grip strength = forearm CSA(0.435). demispan(0.161). exp(3.905 - 0.012 age + 0.413 sex) and plantar flexor strength = leg CSA(0.223). physical activity (0.115). exp(5.867 - 0.015 age + 0.366 sex). These findings indicate that age-related reductions in muscle CSA do not fully account for strength declines with age. Physical activity is also important and partially explains these reductions.