Maximal Oxygen Intake and its Relationship to Endurance Capacity on a Bicycle Ergometer

Abstract

The relationship between maximal oxygen intake (Max V0₂) and the capacity for endurance performance was investigated in a sample of 30 male university students. Each subject performed two work capacity tests on a bicycle ergometer from which continuous, minute-by-minute oxygen intake values, the amount of work performed (kilopond-meters), and the length of the ride (seconds) were obtained. In addition, lean body weight and percent body fat were measured in order to ascertain their importance in the above relationship. The results indicate a fairly high correlation (r = .84) between Max VO₂ (liters/min.) and endurance capacity, but this relationship was reduced considerably when Max VO₂ was expressed relative to body weight (r=.37) and lean body weight (r = .18). However, when the influence of body weight and lean body weight were held statistically constant, the correlations of endurance capacity with Max VO₂ (ml/kg per min.) and Max VO₂ (ml/LBW/ min.) increased to r=.78 and r = .64 respectively. Thus, it was concluded that there is a substantial relationship between endurance capacity and Max V0₂ which is essentially independent of the form in which Max VO₂ is reported providing the influence of body weight and lean body weight on both variables are taken into account.     

Effects of agonist–antagonist complex resistance training on upper body strength and power development

Abstract

The objective of this study was to examine the chronic effects on strength and power of performing complex versus traditional set training over eight weeks. Fifteen trained males were assessed for throw height, peak velocity, and peak power in the bench press throw and one-repetition maximum (1-RM) in the bench press and bench pull exercises, before and after the eight-week programme. The traditional set group performed the pulling before the pushing exercise sets, whereas the complex set group alternated pulling and pushing sets. The complex set training sessions were completed in approximately half the time. Electromyographic (EMG) activity was monitored during both test sessions in an attempt to determine if it was affected as a result of the training programme. Although there were no differences in the dependent variables between the two conditions, bench pull and bench press 1-RM increased significantly under the complex set condition and peak power increased significantly under the traditional set condition. Effect size statistics suggested that the complex set was more time-efficient than the traditional set condition with respect to development of 1-RM bench pull and bench press, peak velocity and peak power. The EMG activity was not affected. Complex set training would appear to be an effective method of exercise with respect to efficiency and strength development.     

The energetics and benefit of an arm swing in submaximal and maximal vertical jump performance

Abstract

The aims of this study were to investigate the energy build-up and dissipation mechanisms associated with using an arm swing in submaximal and maximal vertical jumping and to establish the energy benefit of this arm swing. Twenty adult males were asked to perform a series of submaximal and maximal vertical jumps while using an arm swing. Force, motion and electromyographic data were recorded during each performance and used to compute a range of kinematic and kinetic variables, including ankle, knee, hip, shoulder and elbow joint powers and work done. It was found that the energy benefit of using an arm swing appears to be closely related to the maximum kinetic energy of the arms during their downswing, and increases as jump height increases. As jump height increases, energy in the arms is built up by a greater range of motion at the shoulder and greater effort of the shoulder and elbow muscles but, as jump height approaches maximum, these sources are supplemented by energy supplied by the trunk due to its earlier extension in the movement. The kinetic energy developed by the arms is used to increase their potential energy at take-off but also to store and return energy from the lower limbs and to “pull” on the rest of the body. These latter two mechanisms become more important as jump height increases with the pull being the more important of the two. We conclude that an arm swing contributes to jump performance in submaximal as well as maximal jumping but the energy generation and dissipation sources change as performance approaches maximum.     

The Effect of Preliminary Activity on Maximal Motor Performance

Abstract

This study assessed the effect of five selected treatments of preliminary activity on performance in the 60-yard dash, the cricket ball throw for distance, the jump reach, and the bicycle ergometer test of leg speed. The effect of such preliminary activity at different levels of achievement in the same performance tests was also investigated. An experimental sample of 15- to 17-year-old schoolboys (N = 45) underwent a testing program involving four consecutive days, with two sessions daily. On the basis of measures of pretreatment status, the subjects were matched into groups and subsequently exposed to the treatments. The treatments included identical maximal, identical submaximal, general strengthening, general flexibility and control routines. The statistical analysis of the results involved analysis of variance techniques. There was no evidence available indicating either that the treatments had an effect on the chosen motor performances or that there was a difference in this response at certain levels of achievement. As no measures of physiological function were taken, an assessment of the likely reasons for these findings could not be made.     

Reliability and validity of different methods of estimating the one-repetition maximum during the free-weight prone bench pull exercise

ABSTRACT

This study examined the reliability and validity of three methods of estimating the one-repetition maximum (1RM) during the free-weight prone bench pull exercise. Twenty-six men (22 rowers and four weightlifters) performed an incremental loading test until reaching their 1RM, followed by a set of repetitions-to-failure. Eighteen participants were re-tested to conduct the reliability analysis. The 1RM was estimated through the lifts-to-failure equations proposed by Lombardi and O’Connor, general load-velocity (L-V) relationships proposed by Sánchez-Medina and Loturco and the individual L-V relationships modelled using four (multiple-point method) or only two loads (two-point method). The direct method provided the highest reliability (coefficient of variation [CV] = 2.45% and intraclass correlation coefficient [ICC] = 0.97), followed by the Lombardi’s equation (CV = 3.44% and ICC = 0.94), and no meaningful differences were observed between the remaining methods (CV range = 4.95–6.89% and ICC range = 0.81–0.91). The lifts-to-failure equations overestimated the 1RM (3.43–4.08%), the general L-V relationship proposed by Sánchez-Medina underestimated the 1RM (?3.77%), and no significant differences were observed for the remaining prediction methods (?0.40–0.86%). The individual L-V relationship could be recommended as the most accurate method for predicting the 1RM during the free-weight prone bench pull exercise.     

A quantitative evaluation of the high elbow technique in front crawl

Many coaches often instruct swimmers to keep the elbow in a high position (high elbow position) during early phase of the underwater stroke motion (pull phase) in front crawl, however, the high elbow position has never been quantitatively evaluated. The aims of this study were (1) to quantitatively evaluate the “high elbow” position, (2) to clarify the relationship between the high elbow position and required upper limb configuration and (3) to examine the efficacy of high elbow position on the resultant swimming velocity. Sixteen highly skilled and 6 novice male swimmers performed 25 m front crawl with maximal effort and their 3-dimensional arm stroke motion was captured at 60 Hz. An attempt was made to develop a new index to evaluate the high elbow position (I_he: high elbow index) using 3-dimensional coordinates of the shoulder, elbow and wrist joints. I_he of skilled swimmers moderately correlated with the average shoulder internal rotation angle (r = ?0.652, P < 0.01) and swimming velocity (r = ?0.683, P < 0.01) during the pull phase. These results indicate that I_he is a useful index for evaluating high elbow arm stroke technique during the pull phase in front crawl.     

Relationships among Children's Attitudes,Involvement, and Proficiency in Physical Activities

Abstract

The subjects were 127 boys and 137 girls in grades 4, 5, and 6. Data were collected representing their attitudes toward physical activity, degree of primary involvement in various forms of physical activity, and level of performance in running, jumping, and throwing. Canonical correlation analysis was utilized to examine the nature and degree of the relationships among the children's attitudes, involvement, and proficiency in physical activities. The results suggested a strong relationship between the attitude domain and a combination of the involvement and performance domains; however, there was no common structure to account for the significant canonical relationship between these domains. Further analyses indicated that the basis of this association was the strength of the relationship between the attitude and involvement domains, and that the attitude and performance domains were virtually unrelated. Consideration is given to theoretical and practical implications of these findings.     

Acute intraocular pressure changes during isometric exercise and recovery: The influence of exercise type and intensity,and participant´s sex

ABSTRACT

We assessed the intraocular pressure (IOP) behaviour during a 1-minute period of isometric physical effort and the immediate 1-minute of recovery in the mid-thigh clean pull and squat exercises at three different intensities. Twenty physically active individuals performed the isometric mid-thigh clean pull and squat exercises at three intensities (0% [low-intensity], 25% [medium-intensity] and 50% [high-intensity] of the maximum isometric force). IOP was semi-continuously measured by rebound tonometry. There was a statistically significant effect of exercise intensity on IOP (p < 0.001, ?_p² = 0.416), observing that IOP increments were positively associated with exercise intensity. The mid-thigh clean pull and squat exercises did not demonstrate differences (p = 0.510), and also, no differences were observed between men and women (p = 0.683). The IOP changes during the isometric physical effort showed a positive linear behaviour in all conditions (r = 0.70 to 0.96). IOP returned to baseline levels after 8 seconds of recovery. Our data showed a progressive and instantaneous IOP increment during isometric exercise, which was positively associated with exercise intensity. IOP changes were independent on the type of exercise and participant´s sex. After exercise, IOP rapidly (≈ 8 seconds) returned to baseline levels.     

A Nomogram for the Estimate of Percent Body Fat from Generalized Equations

Abstract

Fifteen well-conditioned college women, who had been thoroughly trained in the correct technique for women's push-ups, were tested for maximal pushing strength in two positions and for the number of complete push-ups they were able to perform at the rate of 41 push-ups per minute. For statistical purposes, calculations of maximal strength for each individual were based upon the average of the recorded maximal arm strengths in the high and low positions plus the average of the weight supported in the high and low positions. The work load was calculated from the distance between the high and low positions, the average supported weight, and the number of push-ups the subject was able to perform until exhausted. A correlation coefficient of .76 was obtained between the calculated maximal strength measures and the work load, indicating a statistically significant positive relationship.     

The relationship between cardiac autonomic function and maximal oxygen uptake response to high-intensity intermittent-exercise training

Abstract

Major individual differences in the maximal oxygen uptake response to aerobic training have been documented. Vagal influence on the heart has been shown to contribute to changes in aerobic fitness. Whether vagal influence on the heart also predicts maximal oxygen uptake response to interval-sprinting training, however, is undetermined. Thus, the relationship between baseline vagal activity and the maximal oxygen uptake response to interval-sprinting training was examined. Exercisers (n?=?16) exercised three times a week for 12 weeks, whereas controls did no exercise (n?=?16). Interval-sprinting consisted of 20 min of intermittent sprinting on a cycle ergometer (8 s sprint, 12 s recovery). Maximal oxygen uptake was assessed using open-circuit spirometry. Vagal influence was assessed through frequency analysis of heart rate variability. Participants were aged 22 ± 4.5 years and had a body mass of 72.7 ± 18.9 kg, a body mass index of 26.9 ± 3.9 kg · m^?2, and a maximal oxygen uptake of 28 ± 7.4 ml · kg^?1 · min^?1. Overall increase in maximal oxygen uptake after the training programme, despite being anaerobic in nature, was 19 ± 1.2%. Change in maximal oxygen uptake was correlated with initial baseline heart rate variability high-frequency power in normalised units (r?=?0.58; P < 0.05). Thus, cardiac vagal modulation of heart rate was associated with the aerobic training response after 12 weeks of high-intensity intermittent-exercise. The mechanisms underlying the relationship between the aerobic training response and resting heart rate variability need to be established before practical implications can be identified.     

On-target trajectories and the final pull in archery

Abstract

At the end of the aiming phase, an archer pulls the arrow back a little bit before he releases the shot. This pulling back of the arrow is called the “final pull”. Simultaneous with the final pull, the archer has to hold the bow calm. The aim of this paper was to examine the motion of the bow and the final pull in highly skilled archers. From a technological point of view, we wished to develop a system to measure the draw-length in the final pull that could be used during archers’ normal training. Seven archers (two males, five females), all of whom were participants at the Junior World Championships and German National Championships, performed 66 shots indoors at a target 30 m away. Each archer shot the same bow as used in competition. On-target trajectories of the aim point movement were measured. Also, the alterations of the draw-length in the final pull were determined. The results suggest that irregularities in the final pull have a negative influence on archers’ scores. Intra-individually, a smaller range of motion of the bow in the last second before the shot appears to have a positive influence on archers’ scores.     

Effects of nicotinamide adenine dinucleotide hydride on physical and mental performance

Abstract

The aim of this study was to assess the effects of nicotinamide adenine dinucleotide hydride (NADH) on maximal oxygen uptake ([Vdot]O_2max), maximal anaerobic running time, and mental performance. Eight men were exposed to a supplement treatment (30 mg NADH as ENACHI tablets per day) and to a placebo treatment, each of 4 weeks' duration, in a balanced, double-blind, and cross-over design. The two treatments were separated by a 14-week wash-out period. The results indicated that [Vdot]O_2max, maximal anaerobic running time, and the ability to concentrate were similar in the NADH and placebo conditions. There were also no differences in blood lactate, creatine kinase, reaction time or feelings of fatigue between the treatments. A counter-movement jump performed at rest and 2 min after the aerobic test differed significantly (P ≤ 0.05) between the treatment conditions and was higher in the NADH group. In conclusion, the NADH supplementation for 4 weeks had no effects on [Vdot]O_2max, maximal anaerobic running time or mental performance.     

Changes in peak leg power induced by successive judo bouts and their relationship to lactate production

Abstract

Eleven male judoka, who compete at national level, were recruited with the aim of investigating changes in peak leg power as a result of successive judo bouts and their relationship with lactate production. The participants executed a force–velocity curve to determine peak power in a 90° squat exercise in concentric work. The group then participated in four 5-min judo bouts each separated by 15 min of passive rest. The power developed as a result of the load associated with the maximum peak power reached in the preliminary test was determined, for the same movement, before and after each bout. Finger capillary blood samples were taken after each bout to determine the maximum lactate concentration achieved and lactate clearance. The results showed no effect of successive bouts on peak leg power (P > 0.05) and no difference when comparing the power measured before and after each bout (P > 0.05). Maximum lactate concentration of the fourth bout was lower than that of the first (12.6 ± 3.5 and 14.6 ± 4 mmol · l^?1 respectively; P < 0.05), although there was no difference in their clearance dynamics (P > 0.05). On the basis of the results obtained, we conclude that successive judo bouts, with the structure proposed in this study, produce high acidosis levels, which have no effect on the peak power developed in the legs.     

Relationship between Motor Performance and Arousal

Abstract

Forty male subjects were tested on a motor learning task called a stabilometer. Skin conductance was taken prior to the introduction of the task and immediately after each of the learning trials. Subjects were then dichotomized on the basis of initial conductance, final conductance, total change in conductance, conductance after trial one, and changes in conductance from rest to trial one. There was no difference in performance between groups when subjects were divided on the basis of initial conductance, but for all other measures performance was significantly better for the group with higher conductance. These results lend support to the concept of an arousal continuum as proposed by Duffy and Malmo.     

Cardiovascular Fitness and Maximal Heart Rate Differences among Three Ethnic Groups

Abstract

The current study examines maximal heart rate and maximal treadmill time differences among three ethnic groups. In 1985, 1,047 city employees (572 male, 475 female) participated in a comprehensive health promotion program. Data were collected from a self-administered health and lifestyle questionnaire, maximal treadmill exercise stress test, and other clinical measures. The participants were divided into white male (n = 368), black male (n = 159), Mexican-American male (n = 45), white female (n = 256), black female (n = 189), and Mexican-American female (n = 30) subgroups based on self-reported ethnic identity. Univariate analyses revealed no significant differences in age-adjusted maximal heart rate or maximal treadmill time for males. Mean age-adjusted treadmill time for black females (478.0 ± 228.2 s) was significantly lower than for white (652.5 ± 227.7 s) and Mexican-American (594.5 ± 226.7 s) females (p <. 05). Mean age-adjusted maximal heart rate for black females (174.4 ± 12.4 beats/min) was significantly lower than for white (179.3 ± 13.4 beats/min) and Mexican-American (182.0 ± 13.5 beats/min) females (p < .05). Following adjustment for cardiovascular fitness level, that is, treadmill time, as well as age, these differences were no longer apparent. We concluded that the comparatively low maximal heart rate of black females may be partially explained by a significantly lower cardiovascular fitness level relative to white and Mexican-American females.     

Kinematic differences between front crawl sprint and distance swimmers at a distance pace

Abstract

The purpose of the study was to determine whether there are differences in kinematics between sprint and distance front crawl specialists when swimming at a distance pace using a six beat kick. Seven sprint and eight distance male specialists performed one maximum 400 m swim through a 6.75 m³ calibrated space recorded by six gen-locked cameras. The following variables were calculated: average swim velocity, stroke length, stroke frequency, upper limb and foot displacement, elbow angle, the shoulder and hip roll angle, duration of the stroke phases and time corresponding to particular events within the stroke cycle relative to hand entry. Differences between the groups were assessed by an independent t-test and effect size (d) calculations for each variable. The groups only differed significantly with respect to the average swim velocity, with the distance swimmers maintaining a greater velocity throughout the 400 m. However, effect sizes were moderate for elbow angle range during the pull phase (d = 0.78) and the total hip roll magnitude (d = 0.76). There was little evidence to suggest that sprint and distance swimmers using a six beat kick pattern differ in technique when swimming at a distance pace and therefore coaches should not encourage the development of different techniques between these groups.     

Biomechanical determinants of cross-country skiing performance: A systematic review

ABSTRACT

Cross-country skiing is a complex endurance sport requiring technical skills, in addition to considerable physiological and tactical abilities. This review aims to identify biomechanical factors that influence the performance of cross-country skiers. Four electronic databases were searched systematically for original articles in peer-reviewed journals addressing the relationship between biomechanical factors (including kinematics, kinetics, and muscle activation) and performance while skiing on snow or roller skiing. Of the 46 articles included, 22 focused exclusively on the classical technique, 18 on the skating technique, and six on both. The indicators of performance were: results from actual or simulated races (9 articles); speed on specific tracts (6 articles); maximal or peak speed (11 articles); skiing economy or efficiency (11 articles); and grouping on the basis of performance or level of skill (12 articles). The main findings were that i) cycle length, most often considered as a major determinant of skiing speed, is also related to skiing economy and level of performance; ii) higher cycle rate related with maximal speed capacity, while self-selected cycle rate improves skiing economy at sub-maximal speeds; iii) cross-country skiing performance appears to be improved by joint, whole-body, ski, and pole kinematics that promote forward propulsion while minimizing unnecessary movement.     

Reliability and Validity of Finger Strength and Endurance Measurements in Rock Climbing

Purpose: An advanced system for the assessment of climbing-specific performance was developed and used to: (a) investigate the effect of arm fixation (AF) on construct validity evidence and reliability of climbing-specific finger-strength measurement; (b) assess reliability of finger-strength and endurance measurements; and (c) evaluate the relationship between finger flexor all-out test scores and climbing ability. Methods: To determine the effect of AF, 22 male climbers performed 2 maximal strength and all-out tests with AF (shoulder and elbow flexed at 90°) and without AF (shoulder flexed at 180° and elbow fully extended). To determine reliability, 9 male climbers completed 2 maximal strength tests with and without AF and an all-out and intermittent test without AF. Results: The maximal strength test without AF more strongly determined climbing ability than the test with AF (r² = .48 and r² = .42 for sport climbing; r² = .66 and r² = .42 for bouldering, respectively). Force and time variables were highly reliable; the rate of force development and fatigue index had moderate and low reliability. The maximal strength test with AF provided slightly higher reliability than without AF (intraclass correlation coefficient [ICC] = 0.94, ICC = 0.88, respectively). However, smaller maximal forces were achieved during AF (484 ± 112 N) than without AF (546 ± 132 N). All-out test average force had sufficiently high reliability (ICC = 0.92) and a relationship to sport climbing (r² = .42) and bouldering ability (r² = .58). Conclusion: Finger strength and endurance measurements provided sufficient construct validity evidence and high reliability for time and force parameters. Arm fixation provides more reliable results; however, the position without AF is recommended as it is more related to climbing ability.     

Accelerometer-measured daily physical activity related to aerobic fitness in children and adolescents

Abstract

Maximum oxygen uptake ([Vdot]O_2PEAK) is generally considered to be the best single marker for aerobic fitness. While a positive relationship between daily physical activity and aerobic fitness has been established in adults, the relationship appears less clear in children and adolescents. The purpose of this paper is to summarise recently published data on the relationship between daily physical activity, as measured by accelerometers, and [Vdot]O_2PEAK in children and adolescents. A PubMed search was performed on 29 October 2010 to identify relevant articles. Studies were considered relevant if they included measurement of daily physical activity by accelerometry and related to a [Vdot]O_2PEAK either measured directly at a maximal exercise test or estimated from maximal power output. A total of nine studies were identified, with a total number of 6116 children and adolescents investigated. Most studies reported a low-to-moderate relationship (r = 0.10–0.45) between objectively measured daily physical activity and [Vdot]O_2PEAK. No conclusive evidence exists that physical activity of higher intensities are more closely related to [Vdot]O_2PEAK, than lower intensities.     

Self-determination,stage of readiness to change for exercise,and frequency of physical activity in young people

Abstract

Release velocity and accuracy are vital components of throwing performance. However, there is no published research on these parameters for throwing in cricket. In this study, we investigated the throwing performance of 110 cricket players from six different populations: elite senior males, elite under-19 junior males, elite under-17 junior males, elite senior females, elite under-19 junior females, and sub-elite senior males. Based on a specifically designed cricket throwing test, participants were assessed for (1) maximal throwing velocity and (2) throwing accuracy at maximal velocity and at three sub-maximal velocities. Elite senior males exhibited the highest peak and mean maximal throwing velocities (P≤0.001). Furthermore, the groups of males had significantly higher peak and mean maximal throwing velocities than the groups of females (P≤0.01). A speed–accuracy trade-off existed such that all groups demonstrated improved accuracy scores at velocities between 75% and 85% maximal throwing velocity compared with 50% maximal throwing velocity and 100% perceived maximal exertion. The results indicate that sex, training experience (years training), and training volume (training time per week) may contribute to throwing performance in cricket players. Further research should focus on understanding the mechanisms behind the observed differences between these groups. This is the first study to describe the inherent throwing profiles of different cricket playing populations. Potentially, we have identified stimulus material for future training developments.