Comment on ‘Ventilation and blood lactate increase exponentially during incremental exercise’ : A reply

Oar force and oar angle data resulting from a 6‐min maximal rowing ergometer test undertaken by novice (n = 9), good (n ‐ 23) and national (n = 9) level male rowers, were used to identify biomechanical performance variables which accurately discriminated between rowers of differing ability levels. The variables included two work capacity measures, mean propulsive power output per kilogram of body mass (W kg^‐1) and propulsive work consistency (%), and two skill variables, stroke‐to‐stroke consistency (%) and stroke smoothness (%). Discriminant function analysis indicated the presence of two functions, both of which clearly indicated the importance of mean propulsive power output per kilogram of body mass as a discriminating variable. Function 2 gave greater weight to stroke‐to‐stroke consistency and stroke smoothness than function 1; however, function 1 was the most powerful discriminator. Classification procedures were used to predict the ability level to which a rower most likely belonged and involved defining the ‘distance’ between each rower and each ability level centroid, with the rower being classified into the ‘nearest’ ability level. These procedures indicated that 100% of the elite, 73.9% of the good, 88.9% of the novice and 82.9% of all rowers were correctly classified into their respective skill levels. Stepwise discriminant analysis included the variables in the following order: mean propulsive power output per kilogram of body mass, stroke‐to‐stroke consistency, stroke smoothness and propulsive work consistency (P < 0.001). The results of this study indicate that biomechanical performance variables related to rowing capacity and skill may be identified and used to discriminate accurately between rowers of differing skill levels, and that, of these variables, propulsive work consistency is the least effective discriminator.     

Age,Physical Activity,Physical Fitness,Body Composition,and Incidence of Orthopedic Problems

Abstract

The incidence of orthopedic problems was examined in 5, 582 men and women who attended the Cooper Clinic in Dallas, Texas between 1974 and 1982. The effects of age, physical activity, physical fitness, and body mass index (EMI) on the occurrence of these problems were examined using a proportional hazards approach. The expected risk of orthopedic problems per person-year was 0.045 for men and 0.046 for women. For men, physical fitness, BMI, and physical activity were associated with orthopedic problems, while for women, physical activity was the main predictor. Age was not a factor for either gender. The effect of change in physical fitness, physical activity, and BMI was examined in a subset of 2, 325 persons with more than one visit to the clinic. For women, physical activity and a decrease in BMI were associated with orthopedic problems, while for men none of those factors were significant. Again, age was not a factor in either group. The absence of any age effect on the occurrence of problems suggests that with regard to orthopedic problems, moderate amounts of physical activity in generally healthy persons may be recommended without special consideration as to age.     

Lactate and Phosphagen Levels in Muscle Immediately after a Maximum 300 m Run at Sea Level

Abstract

The relative effectiveness of six intensive training programs on the development of four selected skills was studied, with emphasis on limited time encountered within the semester organizational plan. One hundred and twenty college freshmen men volunteers were randomly assigned to training groups of 30 members each, which met for two sessions a week for 16 weeks.

Results indicated that: (a) direct practice jumping, alone or combined with repetitive sprinting or weight training, was significantly superior to weight training alone on standing broad jump development; (b) direct practice of a zigzag run was superior to both weight training and repetitive sprinting; and (c) when group acquisition of “adequate” skill is the objective, performance improvements educed over the first nine weeks were great enough to question the merits of persisting at an activity over a full semester. Only the zigzag run was adversely affected by the spring vacation cessation of training.     

On Publishable Research Articles

To assess the role of qualitative knowledge of results (KR) in children's motor learning, four-year-old subjects performed a linear positioning task. Children were divided into three groups, each varying on KR precision. A significant reduction in variable error (p < .05) over trials seemed to indicate that children can utilize KR to become more consistent in learning. No significant differences were found among the three KR groups; however, the most precise KR condition tended to show fewer errors than the least precise KR condition. Some recommendations for future research are discussed.     

Individual t Tests versus Multiple Range Tests

Abstract

In an effort to determine the better method of starting and running to the right, two methods, the jab step and the cross-over step, were compared. Thirty male students, 13–17 years old, were timed at four testing stations, 5, 11, 22, and 37 feet from the start. Reliabilities were very high. Analysis of variance revealed the cross-over step to be significantly faster than the jab step at each timing station.     

Cardiopulmonary loading in motocross riding

Abstract

The present study was designed to examine physiological responses during motocross riding. Nine Finnish A-level motocross riders performed a 15-min ride at a motocross track and a test of maximal oxygen uptake ([Vdot]O_2max) in the laboratory. Cardiopulmonary strain was measured continuously during the ride as well as in the [Vdot]O_2max test. During the ride, mean [Vdot]O₂ was 32 ml · kg^?1 · min^?1 (s = 4), which was 71% (s = 12) of maximum, while ventilation (V _E) was 73% (s = 15) of its maximum. The relative [Vdot]O₂ and V _E values during the riding correlated with successful riding performance (r = 0.80, P < 0.01 and r = 0.79, P < 0.01, respectively). Mean heart rate was maintained at 95% (s = 7) of its maximum. Mean blood lactate concentration was 5.0 mmol · l^?1 (s = 2.0) after the ride. A reduction of 16% (P < 0.001) in maximal isometric handgrip force was observed. In conclusion, motocross causes riders great physical stress. Both aerobic and anaerobic metabolism is required for the isometric and dynamic muscle actions experienced during a ride.     

Effect of cluster set configurations on power clean technique

Abstract

The purpose of this investigation was to examine the effects of cluster set configurations on power clean technique. Ten male, recreational weightlifters performed three sets of six repetitions at 80% of one repetition max with 0 (P0), 20 (P20) or 40 seconds (P40) inter-repetition rest. During the first and second set of P0, the catch and first pull were in a more forward position during repetition 6 as compared to repetition 1, respectively. During the second set of P40, differences in horizontal displacement were found between repetitions 1 and 6 for the second pull and the loop. During the third set of P40, differences in horizontal displacement were found between repetitions 1 and 6 for the first pull, transition, and beginning of the second pull. No differences in horizontal displacement were found between repetitions 1 and 6 during P20. During each set of P0, vertical displacement decreased between repetitions 1 and 6 (1.02 ± 0.07 m vs. 0.94 ± 0.06 m; Mean ± s). Cluster set configurations led to the maintenance of vertical displacement throughout all sets. The results demonstrate cluster set configurations with greater than 20 seconds inter-repetition rest maintain weightlifting technique to a greater extent than a traditional set configuration.     

Interactions among Dietary Pattern,Physical Activity and Skinfold Thickness

Abstract

This study was designed to assess the effects of a specifically designed perceptual-motor training program on the level of perceptual-motor development, self-concept, and academic ability of kindergarten children. Subjects for the study were 40 kindergarten children randomly assigned to 1 of 2 groups. Each group received the same kindergarten program with one exception, the experimental group was exposed to a specifically designed perceptual-motor program 30 min daily for 5 mo, while the control group received a free play period for 30 min daily. Results of the study indicated that the data tended to support the specificity of training concept. The variables showing the greatest change were the perceptual-motor tests which measured changes on specific aspects of the training program. There appeared to be some immediate transfer to academic abilities but this was not pronounced enough to suggest that perceptual-motor training was of real benefit in developing academic abilities for normal kindergarten children. In addition the follow-up test indicated no long term effects on academic performance.     

Effect of Caffeine Ingestion on Cardiorespiratory Endurance in Men and Women

Abstract

The effect of caffeine ingestion on submaximal endurance performance of 15 females and 13 males was investigated. After completing a [Vdot]O ₂ max test, each subject performed two submaximal cycling tests at approximately 75% of [Vdot]O ₂ max to exhaustion. For the caffeine (C) trials, 300 mg of caffeine was added to 250 ml of decaffeinated coffee and ingested one hour prior to the exercise. The decaffeinated (D) trial involved consuming 250 ml of decaffeinated coffee an hour prior to the test. The C and D trials were administered randomly using a standard double blind design. Physiological parameters were monitored each 9, 10, and 11 minute intervals throughout each trial and averaged. As expected the [Vdot]O ₂ (L · min ^?1 ), [Vdot]E and work outputs (kgm) were significantly (p < 0.001) higher for the males than the females. All other variables, time to exhaustion, [Vdot]O ₂ (ml · kg · min ^?1 ), R, HR, and rating of perceived exertion (RPE) were not significantly (p > 0.05) different between the sexes for either the C or D trials. Time to exhaustion was 14.4 and 3.1% longer for the C trials for the females and males, respectively, however these increases were not significant (p > 0.05). Furthermore, there were no significant differences (p > 0.05) for any of the measured variables during successive 10 minute work intervals between the C and D trials for either sex. These results do not support the general use of caffeine in moderate amounts as an ergogenic aid for either males or females, but from a practical point it appears that caffeine may have an ergogenic effect on specific individuals.     

Cognitive Style and Learner Strategy Interaction in the Performance of Primary and Related Maze Tasks

Abstract

The effect of designated learning strategies and reflective versus impulsive cognitive styles on performance in a maze learning task was investigated. Twenty-four female subjects were randomly assigned to a strategy or control group. The strategies group was provided with three potentially effective strategies (imagery, rhythm, and feedback) as identified by an information processing task analysis procedure. The Matching Familiar Figures test further classified subjects within the two groups according to their preferred styles of responding. Eleven primary task trials were administered with direct view of maze and four related task trials were completed with an indirect view of it. Traversal speed and time in the incorrect pathways were analyzed with a 2 × 2 × 7 (Strategies × Cognitive Styles × Trial Blocks) repeated measures ANOVA. A significant three-way interaction was found for both dependent measures. As hypothesized, during the primary task the control reflective subjects traversed the maze more slowly than the control impulsive subjects. However, the strategies reflective subjects completed the maze with the same speed as strategies impulsives. The incorrect pathways × time interaction revealed that the control reflective subjects spent less time in the incorrect pathways during the related task than the control impulsives. No significant differences were found for strategies reflectives or impulsives. These findings indicate that, for this maze task that emphasized speed, the performance of reflective and impulsive subjects was facilitated by appropriate learning strategies.