Biomedical subjects

R Callister

Publications and source records attributed to R Callister.

23 records · Page 2Linked to original sources

PubMed1991

Physiological characteristics of elite judo athletes.

In order to provide some understanding of the physiological capacities underlying successful judo performance, representative values for a variety of physiological variables were determined in nationally ranked male (n = 18) and female (n = 9) judo athletes. Body composition, aerobic capacity, isokinetic elbow and knee flexor and extensor strength, and muscle fiber size and composition of the vastus lateralis were examined. Comparisons across weight divisions indicate that the values of many characteristics varied as a function of size. As weight division increased, relative VO2 decreased (r = -0.53 and -0.63 for males and females, respectively), % body fat increased (r = 0.64, 0.72), and the cross sectional areas of Type I (r = 0.55, 0.77) and Type IIA (r = 0.47, = 0.76) muscle fibers increased. Among females in particular, athletes in the higher weight divisions were stronger relative to LBM than those in the lower division. These results indicate that the physiological profiles of lower and upper weight division elite judo players differ markedly. It is suggested that the factors responsible for success may be specific to each weight division and may represent a compromise between making weight and maximizing physiological capacities and performance.

Adipose Tissue↗

PubMed1990

Physiological and performance responses to overtraining in elite judo athletes.

To determine the effect of large and sudden increases in training volume on performance characteristics and the feasibility of using overtraining syndrome symptoms to monitor performance changes, 15 elite judo athletes were examined through 10 wk of training. Athletes performed their regular regimens of resistance (3 d.wk-1), interval (2 d.wk-1), and judo (5 d.wk-1) training in weeks 1-4. Interval and resistance training volumes increased by 50% in weeks 4-8 and returned to baseline in weeks 9-10. Judo training volume was unchanged in weeks 1-8 but increased by 100% in weeks 9-10. Assessments were made in weeks 2, 4, 8, and 10. Isokinetic strength of elbow and knee extensors and flexors increased significantly from weeks 2 to 4 (3-13%), was unchanged from weeks 4 to 8, and decreased significantly (6-12%) from weeks 4 to 10. Total time for 3 x 300 m intervals increased (P less than 0.05) between weeks 2 and 4 and between weeks 4 and 8, while total time for 5 x 50 m sprints decreased (P less than 0.05) from weeks 8 to 10 (less than 2%). Body fat percentage decreased (P less than 0.05) from weeks 2 to 10. Body weight, submaximal and maximal aerobic power, resting (sleeping) systolic and diastolic pressures, resting (sleeping) submaximal and maximal heart rates, exercising blood lactate levels, and vertical jump performance did not change significantly with increases in training volume. These results suggest that 6 wk of overtraining may affect some but not all aspects of performance and that performance may be affected before symptoms of the overtraining syndrome appear.

Adult↗

PubMed1989

Histochemical classification of neck and limb muscle fibers in a turtle, Pseudemys scripta: a study using microphotometry and cluster analysis techniques.

We have attempted to develop an objective, semiquantitative classification of fiber types in turtle neck and limb muscle using microphotometry and multivariate statistical techniques. We first stained serial sections for myosin adenosine triphosphatase (ATPase) (with acid and alkaline preincubation and without preincubation), NADH-diaphorase, and two glycolysis-associated markers, alpha-glycerophosphate dehydrogenase (alpha-GPDH) and glycogen phosphorylase A (GPA). This allowed us to characterize individual muscle fibers in terms of their contraction speed and metabolic properties. Next we used microphotometry to measure the optical density of the reaction product in each fiber, and we subjected the resulting optical density matrix to cluster and discriminant function analyses in order to assign fibers to groups (fiber types) and to determine which stains contribute most to the distinction between groups. As a control, we processed a well characterized mammalian muscle (rat sternomastoid) simultaneously. Our results suggest that both neck and limb muscle in Pseudemys can best be described as falling into three groups: 1) slow oxidative (SO) fibers; 2) fast oxidative glycolytic (FOG) fibers, with relatively high oxidative and glycolytic capacities; and 3) fast glycolytic (Fg) fibers, with low oxidative, low/intermediate alpha-GPDH, and high GPA activities. These three fiber types differ from like-named types in rat muscle both in the pH lability of their myosins and in their metabolic profiles.

Animals↗

PubMed1989

Training responses of plasma beta-endorphin, adrenocorticotropin, and cortisol.

The purpose of this study was to examine the effects of three different run training programs on plasma responses of beta-endorphin (beta-EP), adrenocorticotropin (ACTH), and cortisol to maximal treadmill exercise. Subjects were randomly assigned to one of three training groups: sprint intervals (SI) (N = 8), endurance (E) (N = 10), or combination (C) (N = 7). Training was monitored for 10 wk, and maximal treadmill exercise tests were administered pre-training and after 2, 4, 6, 8, and 10 wk of training. Blood samples were obtained (pre-training and after 10 wk) before, immediately after, and 5 and 15 min following the maximal exercise tests. All groups significantly (P less than 0.05) increased maximal oxygen consumption values at 8 and 10 wk of the training period. Significant exercise-induced increase in plasma beta-EP, ACTH, cortisol, and blood lactate were observed for both pre- and post-training tests in all training groups. The SI group demonstrated significant post-training increases in beta-EP, ACTH, cortisol, and 5 min post-exercise blood lactate concentrations in response to maximal exercise. No training-induced hormonal changes were observed for the E group. While exercise-induced increases were observed, the C group exhibited significant post-training reductions in plasma responses of beta-EP, ACTH, and blood lactate concentrations in response to maximal exercise. Still, resting and post-exercise increases in plasma cortisol concentrations were significantly higher in magnitude in the post-training test. Lactate was significantly correlated with beta-EP (r = 0.72), ACTH (r = 0.70), and cortisol (r = 0.64).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗

PubMedDate not supplied

Human torque velocity adaptations to sprint, endurance, or combined modes of training.

We had groups of athletes perform sprint and endurance run training independently or concurrently for 8 weeks to examine the voluntary in vivo mechanical responses to each type of training. Pre- and posttraining angle-specific peak torque during knee extension and flexion were determined at 0, 0.84, 1.65, 2.51, 3.35, 4.19, and 5.03 radian.sec-1 and normalized for lean body mass. Knee extension torque in the sprint-trained group increased across all test velocities, the endurance-trained group increased at 2.51, 3.34, 4.19, and 5.03 radian.sec-1, and the group performing the combined training showed no change at any velocity. Knee flexion torque of the sprint and combined groups decreased at 0.84, 1.65, and 2.51 radian.sec-1. Knee flexion torque in the sprint-trained group also decreased at 0 radian.sec-1 and in the combined group at 3.34 radian.sec-1. Knee flexion torque in the endurance-trained group showed no change at any velocity of contraction. Mean knee flexion:extension ratios across the test velocities significantly decreased in the sprint-trained group. Knee extension endurance during 30 seconds of maximal contractions significantly increased in all groups. Only the sprint-trained group showed a significant increase in endurance of the knee flexors. These data suggest that changes in the voluntary in vivo mechanical characteristics of knee extensor and flexor skeletal muscles are specific to the type of run training performed.

Adaptation, Physiological↗