Effect of Toe Clips during Bicycle Ergometry on [Vdot]O2 max

Abstract

Previous investigators have yielded conflicting results in testing the hypothesis that the use of toe clips during bicycle ergometry produces a higher maximal oxygen uptake ([Vdot]O ₂ max) than testing without toe clips. Eight men, four competitive cyclists and four competitive distance runners volunteered to participate in three randomized [Vdot]O ₂ max tests: 1) a treadmill running lest, 2) a bicycle ergometer test using standard toe clips, and 3) a test on the same ergometer without toe clips. The highest mean [Vdot]O ₂ max was observed in the treadmill condition as expected. However, no statistically significant difference in mean [Vdot]O ₂ max or performance time was observed between the toe-clip and no toe-clip conditions. Based on these results, the research hypothesis was rejected and no favorable physiological effect may be attributed to the use of toe clips.     

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.     

Training Responses of Speed Skaters during a Competitive Season

Abstract

The purpose of this study was to test the effects of a 10-month exercise program on bone mineral content (BMC) and bone mineral content/bone width (BMC/BW) of postmenopausal women. Thirty-one women (ages 57-83) completed either a general aerobics exercise program (n = 10), a general aerobics plus upper body weight training exercise program (n = 10), or served as nonexercising control subjects (n = 11). Average compliance rates for the exercise subjects ranged from 72 to 80%. All subjects were pre- and posttested for BMC and BMC/BW in the radius of the nondominant forearm. ANOVA results indicated that there were significant differences between the exercise and control subjects in the amount of change in BMC and in BMC/BW (p < .05) during the course of the study. The exercise subjects experienced mean increases of 1.38% and 1.33% in BMC and BMC/BW, respectively, whereas the control group had decreases of 2.50% and 258%. No significant differences were found for subjects in the two types of exercise programs, suggesting that the effects of exercise relative to maintenance of bone density may be general as well as localized.     

Alterations in Strength and Maximal Oxygen Uptake Consequent to Nautilus Circuit Weight Training

Abstract

The purpose of this study was to determine the effects of a Nautilus circuit weight training program on muscular strength and maximal oxygen uptake ([Vdot]O ₂ max) by comparing these effects to those produced by adhering to either a free weight (FW) strength training program or a running (R) program. Male college students who voluntarily enrolled in either a FW training class (n = 11), a Nautilus (N) circuit weight training class (n= 12), or a R conditioning class (n= 13) were subjects for this investigation. All groups participated in their respective programs 3 days per week for 10 weeks. Strength was assessed using a Cybex II isokinetic dynamometer set at an angular velocity of 60° · s ^?1 and a damping of 2. The FW group served as the control group for the assessment of [Vdot]O ₂ max changes, while the R group served as controls for the assessment of strength differences. ANCOVA revealed that the N and R groups experienced significant (p < .01) increases in [Vdot]O ₂ max expressed in L · min ^?1 (10.9 and 11.4%), ml · kg ^?1 · min ^?1 (10.8 and 11.7%), and ml · kgLBW ^?1 · min ^?1 (7.1 and 7.5%) when compared to the FW group. There were no significant differences between the N and R groups. There were no significant differences among groups in final peak torque values (after covariance), and torque at the beginning and end of the range of motion for the knee extensors, knee flexors, elbow extensors, and elbow flexors. In general, isokinetic strength values elicited by the N group compared favorably to those generated by the FW group. It was concluded that for a training period of short duration, Nautilus circuit weight training appears to be an equally effective alternative to standard free weight (strength) and aerobic (endurance) training programs for untrained individuals.     

The Estimation of [Vdot]O2max from Maximal and Sub-Maximal Measurements in Males,Age 10–39

Abstract

The purpose of this study was to assess the relationship between physiological and anthropometrical variables and 15-km time trial (TT) cycling performance time. Twenty-two competitive cyclists averaged 59.7 ml · kg^–1 · min^–1 for maximal oxygen consumption ([Vdot]O_2max), 42.8 ml · kg^–1 · min^–1 for anaerobic threshold (AT), and 23.5 min for the 15 km TT race. The relationship between [Vdot]O_2max and cycling performance time was r = – 0.68, (p < .01) while the correlation between AT and performance time was r = – 0.93, (p <.01). Applying stepwise multiple regression analysis, the two-variable model of the AT and the body circumference ratio, thigh+calf:arm+chest, was found to correlate highly with cycling performance time (r =0.966). It was concluded that the successful cyclists are characterized by the ability to consume large amounts of oxygen prior to ventilatory changes associated with the anaerobic threshold as well as a larger lower to upper body circumference ratio which may favorably decrease wind resistance while cycling.     

Physiologic Effects of Distance Running Training on Teenage Females1

Abstract

The purpose of this study was to investigate selected physiological changes that occurred with distance training in teenage females. Two groups of untrained teenage females were matched on [Vdot]O₂ max, percent utilization of [Vdot]O ₂ @ 9.66 km/hr, peak heart rate, and percent body fat. One group served as control (n = 9) while the other (n =10) underwent a 20-week training program designed to gradually increase the subjects' average mileage from 0 to 32.2 km per week. At the end of the 20 weeks, a MANOVA revealed significant mean differences within the trained group and no significant mean differences within the control group. The univariate analysis revealed that significant (p <0.05) mean differences found within the training group were for [Vdot]O ₂ max (45.1 vs. 49.3 ml · kg ^–1 · min ^–1 ), percent utilization of [Vdot]O ₂ @9.66 km/hr (76.5% vs. 67.5%), and economy VO ₂ @9.66 km/hr (34.5vs.33.2 ml · kg ^–1 · min ^–1 ). Of the variables which exhibited significant training effects, percent utilization of [Vdot]O ₂ max showed the greatest relative change, a 12.2% decrease, with [Vdot]O ₂ max showing a 9.3% increase. The posttest results were similar to the research literature for training effects found for males and other age groups.     

A Reliable Method for the Measurement of Constant Load Maximal Endurance Performance on the Bicycle Ergometer

Abstract

The purpose of this study was to examine the relationships of achievement goal orientations and perceived motivational climate to perceptions of the intensity and direction of competitive state anxiety in a sample of university athletes representing various team sports. Although some studies have demonstrated that task orientation and mastery climate are associated with adaptive emotional patterns and ego orientation and performance climate are linked to less adaptive emotions, others have not verified these findings. In the present study, structural equation modeling was used to test these links. The results showed that perceptions of a performance climate were associated with ego orientation, whereas perceptions of a mastery climate were linked to task orientation. Furthermore, no significant links were found between task orientation and direction of competitive anxiety, while it was shown that the impact of ego orientation on the intensity and direction of cognitive and somatic anxiety was exerted through self-confidence. No significant direct links were found between motivational climates and competitive anxiety, thus implying that motivational climates may have an indirect impact on affective responses through the different goal orientations. The findings of the present study are discussed along with suggestions for examining situational and individual difference variables that may explain the relationships between intensity and direction of competitive anxiety and achievement goals and motivational climates.     

Pygmalion in the Gym: A Model for the Communication of Teacher Expectations in Physical Education

Abstract

Much research on teacher expectations has focused on ways in which teacher perceptions of student ability can ultimately affect student performance. The majority of this research has indicated that teacher expectations not only determine certain types of student performance, but also serve to sustain low and high levels of performance. Observational research has also demonstrated that differential teacher-student interactions are related to certain levels of teacher expectations. For example, it has been shown that high expectancy students receive more praise, acceptance of ideas, contact and wait time, and more response opportunities than low expectancy students. Much of this research has been generated from studies related to classroom instruction. Very little of this research, however, has been operational in the physical education setting. One reason for this is the absence of a model in physical education through which this type of research can be generated. This article presents such a model showing how expectations are formed, how they are communicated, and how they sustain low and high levels of student growth and performance. The model further illustrates the causal relationship among teacher expectations, dyadic interactions and student growth and performance. Suggestions for future research techniques to determine causal flow among variables are also presented.     

Validity of Palpation Recovery Pulse Rate to Estimate Exercise Heart Rate Following Four Intensities of Bench Step Exercise

Abstract

Previous investigations regarding activity during the post-knowledge of results (KR) interval have considered the performance of interference groups over KR-supplied acquisition trials as indicative of effects upon learning. The absence of transfer tests in these studies, however, preclude such an assumption. Indeed, the use of a retention test in the present investigation (no-KR trials following an interpolated phase) provided evidence suggesting that, while activity during the post-KR interval is detrimental to performance, no such assumption can be made regarding this effect upon learning. These findings are discussed relative to recent arguments that some of the commonly accepted “Laws of KR” may be contradictory when applied simultaneously to motor learning and performance.     

Physiological Profiles of High School Female Cross Country Runners

Abstract

Percent body fat, ratings of perceived exertion and maximal oxygen consumption during a continuous running treadmill test were obtained on 127 high school female cross country runners. These young runners (x 15.6 yrs) were running approximately 25 miles per week at the time of testing. They had an average [Vdot]O₂ max of 50.8 ml · min^-1 and an HR max of 198.0 bpm. The mean percent body fat, as determined from hydrostatic weighing, was 15.4%. The onset of metabolic acidosis was estimated to occur at 78% of [Vdot]O₂ max. A stepwise multiple regression with the 3000 meter run as the dependent variable indicated that max treadmill run time, weight relative [Vdot]O₂ max and [Vdot] max entered the equation in that order, yielding an R of 0.67. Both HR and RPE increased with work intensity, but not at equal rates. These high school female runners had higher [Vdot]O₂ max's than previously reported for this age group; however, they were considerably below these values reported for national caliber distance runners.     

Evaluation of the exercise workload of broadcast calisthenics for children and adolescents aged 11–17 years

Abstract

The aim of this study was to examine the exercise workload of the 3rd Series of National Broadcast Calisthenics for Elementary and Middle School Students. Altogether, 120 students aged 11–17 years were randomly selected from elementary and middle schools to participate in the study. Each participant performed a cycle ergometer test to obtain maximum oxygen uptake ([Vdot]O_2max) and maximum heart rate values. In the laboratory, oxygen uptake ([Vdot]O₂), metabolic equivalents (METs), and heart rate were recorded continuously throughout a calisthenics session performed by the participants. Ratings of perceived exertion (RPE) were also recorded. Throughout the calisthenics session, mean percentage of [Vdot]O₂ reserve varied from 30.7% to 41.2%, mean percentage of heart rate reserve from 39.0% to 56.9%, and mean RPE from 9.0 to 10.4. The mean energy cost during most of the segments across the four routines of calisthenics was significantly higher (P < 0.05) than 3.0 METs. In conclusion, the exercise workload of the 3rd Series of National Broadcast Calisthenics for Elementary and Middle School Students session varied from low to moderate. As part of a school-based physical activity intervention project, calisthenics would help to promote an active lifestyle and health in children and adolescents.     

电刺激对过氧化氢诱导衰老肌管细胞能量代谢的影响

目的：运用电刺激肌管细胞收缩模拟骨骼肌收缩,并观察其对过氧化氢（H₂O₂）诱导的C₂C₁₂细胞衰老模型能量代谢相关指标表达的影响,以此研究体外肌管收缩对衰老骨骼肌细胞能量代谢影响的分子机制。方法：使用不同浓度的H₂O₂诱导肌管细胞建立衰老模型,并用β-半乳糖苷酶染色检测衰老水平;电刺激干预培育成功的衰老肌细胞,并分为对照组（C组）、H₂O₂诱导衰老组（H组）、对照+电刺激组（CE组）、H₂O₂诱导衰老+电刺激组（HE组）。各组细胞通过Western blot法对PGC-1α蛋白表达进行检测,ATP水平测试盒测量ATP水平。结果：经过浓度为100 μmol/L H₂O₂诱导肌管细胞24 h后成功构建骨骼肌细胞衰老模型。与C组比较,H组的ATP水平表达呈非常显著性的下降（P＜0.01）;CE组的ATP水平较C组呈非常显著性升高（P＜0.01）;HE组的ATP水平虽低于C组,但高于H组,且呈非常显著性差异（P＜0.01）;与C组相比,H组PGC-1α蛋白表达下降,呈非常显著性差异（P＜0.01）;HE组PGC-1α蛋白表达虽低于C组,但较H组呈非常显著性升高（P＜0.01）。结论：H₂O₂是诱导骨骼肌肌管细胞衰老的一种有效方式,衰老肌管细胞的ATP和PGC-1α蛋白表达水平显著下降,进行电刺激干预后可以有效提高衰老肌管细胞ATP水平和PGC-1α蛋白表达。     

Physical Characteristics and Oxygen Utilization of Male and Female Marathon Runners

Verbal and nonverbal communication is a critical mediator of performance in team sports and yet there is little extant research in sports that involves direct measures of communication. Our study explored communication within NCAA Division I female tennis doubles teams. Video and audio recordings of players during doubles tennis matches captured the communications that took place between and during points. These recordings were coded and sequential analysis computed using the Discussion Analysis Tool software (Jeong, 2003). Results indicated that most communications were emotional (i.e., > 50%) or action statements (i.e., > 25%). Winning teams exhibited significantly different communication sequences than losing teams. In particular, winning teams had a more homogeneous model of communication, which perhaps makes message interpretation more reliable. Finally, winning teams exchanged twice as many messages as losing teams.