Search Results

You are looking at 91 - 100 of 3,197 items for :

Clear All
Restricted access

Martin J. MacInnis, Aaron C.Q. Thomas and Stuart M. Phillips

than there is examining fixed-distance TTs. The mean power output (MPO) achieved during a 60-minute TT is a standard performance measure in cycling. In a study by Coyle et al, 3 60-minute MPO was the strongest predictor for the time required by well-trained cyclists to complete 40-km TTs in the field

Restricted access

Gabriel Rodríguez-Romo, Thomas Yvert, Alfonso de Diego, Catalina Santiago, Alfonso L. Díaz de Durana, Vicente Carratalá, Nuria Garatachea and Alejandro Lucia

The authors compared ACTN3 R577X genotype and allele frequencies in the majority of all-time-best Spanish judo male athletes (n = 108) and 343 ethnically matched nonathletic men. No between-groups differences were found in allele (P = .077) or genotype distributions (P = .178). Thus, the R577X polymorphism was not significantly associated with the status of being an elite judo athlete, at least in the Spanish population. The contribution of genetics to sports-related phenotype traits is undeniable with some genotypes, of which ACTN3 R577X is currently the leading candidate, partly distinguishing individuals predisposed to either endurance or power sports. However, few athletic events can be categorized as purely power or endurance based. Although genetic testing (ie, for ACTN3 R577X) is already being marketed to predict sports talent and potential of young children, its usefulness is still questionable, at least in competitive judo.

Restricted access

Dominic Malcolm, Claudia Pinheiro and Nuno Pimenta

This paper provides sociological reflections on the professionalization of sport coaching and the attempts of sport coaches to attain such a status. It explicates existing sociological analyses of the professions, highlighting and critiquing the so-called “trait” approach which currently dominates discussions of the professionalization of sport coaching. It subsequently suggests that the “power approach” to professions, as epitomized by the work of Johnson, Larson and Abbott, provides a more realistic depiction of professionalization, alerting us to the conflictual and exclusionary aspects endemic in such a process. Finally the paper explores some twenty-first century trends towards the declining influence and social power of professional groups, and the specific characteristics and social standing of sport coaching which will serve to constrain sport coaches from achieving the goal of professional status. This analysis leads us to question whether professionalization should be viewed as an inherently “positive” development, and whether professionalization is a realistic goal for an occupational group such as sport coaching.

Restricted access

Wioletta Brzenczek-Owczarzak, Mariusz Naczk, Jaroslaw Arlet, Justyna Forjasz, Tomasz Jedrzejczak and Zdzislaw Adach

This study aimed to estimate the efficacy of inertial training in older women using the Inertial Training and Measurement System (ITMS), an original device. Forty-five active women age 53–74 yr performed inertial training with 2 different loads (0 or 5 kg) 3 times weekly for 4 wk. Training sessions consisted of exercises involving the shoulder muscles of the dominant and nondominant arms. The maximal torque and power developed by the dominant and nondominant arms in the 0-kg and 5-kg groups were significantly greater after 4 wk of inertial training (with the exception of torque for the nondominant arm in the 5-kg group; p > .05). Thus, short-term training using the ITMS is efficacious and can be used in older women to improve strength and power. However, ITMS training-induced changes in older women are greater after application of smaller external loads.

Restricted access

Nicholas Caplan and Trevor N. Gardner

The aim of the present study was to determine the effect of varying the height of the foot stretcher on the mechanical effectiveness of rowing. Ten male university level rowers rowed maximally for 3 minutes 30 seconds on a modified Concept 2 rowing ergometer. Each participant completed one trial at three foot stretcher heights. Position 1 was the original Concept 2 stretcher position, with Position 2 being located 5 cm and Position 3 being 10 cm above the original position and in the same orientation. Pull force and velocity were measured, and mean power generated by the rowers was calculated for each stroke. It was shown that in all three stretcher positions, mean power per stroke decreased as a function of time during the trial, confirming the fatiguing effects of the task. Although mean power per stroke did not differ significantly between stretcher positions at the start of the trial, p = 0.082, a significant difference was observed between the original stretcher position and Positions 2 and 3 at the end of the trial, p < 0.05. The lowest decline in mean power occurred in the highest stretcher position. It is suggested that this improvement in effectiveness is due to a reduction in the active downward vertical forces applied to the foot stretchers which does not contribute to forward propulsion, and thus a reduction in energy waste during each stroke. It was hypothesized that further raising the stretchers will continue to lead to an improvement in effectiveness until the optimum stretcher height is reached, above which effectiveness will be reduced.

Restricted access

Pedro Jiménez-Reyes, Fernando Pareja-Blanco, Carlos Balsalobre-Fernández, Víctor Cuadrado-Peñafiel, Manuel A. Ortega-Becerra and Juan J. González-Badillo

Purpose:

To examine the relationship between the relative load in full squats and the height achieved in jump-squat (JS) exercises and to determine the load that maximizes the power output of high-level athletes.

Method:

Fifty-one male high-level track-and-field athletes (age 25.2 ± 4.4 y, weight 77. ± 6.2 kg, height 179.9 ± 5.6 cm) who competed in sprinting and jumping events took part in the study. Full-squat 1-repetition-maximum (1-RM) and JS height (JH) with loads from 17 to 97 kg were measured in 2 sessions separated by 48 h.

Results:

Individual regression analyses showed that JH (R 2 = .992 ± .005) and the jump decrease (JD) that each load produced with respect to the unloaded countermovement jump (CMJ) (R 2 = .992 ± 0.007) are highly correlated with the full-squat %1-RM, which means that training intensities can be prescribed using JH and JD values. The authors also found that the load that maximizes JS’s power output was 0%RM (ie, unloaded CMJ).

Conclusions:

These results highlight the close relationship between JS performance and relative training intensity in terms of %1-RM. The authors also observed that the load that maximizes power output was 0%1-RM. Monitoring jump height during JS training could help coaches and athletes determine and optimize their training loads.

Restricted access

Trynke Hoekstra, Colin A. Boreham, Liam J. Murray and Jos W.R. Twisk

Background:

It is not clear what the relative contribution is of specific components of physical fitness (aerobic and muscular) to cardiovascular disease (CVD) risk. We investigated associations between aerobic fitness (endurance) and muscular fitness (power) and CVD risk factors.

Methods:

Data were obtained from the Young Hearts project, a representative sample of 12- and 15-year-old boys and girls from Northern Ireland (N = 2016). Aerobic fitness was determined by the 20-m shuttle run test, muscular fitness by the Sargent jump test. CVD risk factors included sum of skinfolds, systolic and diastolic blood pressure, serum total cholesterol (TC), HDL cholesterol, and TC:HDL ratio. Several linear regression analyses were conducted for 4 age and gender groups separately, with the risk factor as the outcome variable.

Results:

Significant associations between aerobic fitness and a healthy CVD risk profile were found. These observed relationships were independent of power, whereas the (few) relationships between muscular fitness and the risk factors were partly explained by endurance.

Conclusions:

Tailored, preventive strategies during adolescence, incorporating endurance rather than power sports, could be encouraged to help prevent CVD. This is important because existing studies propose that healthiness during adulthood is founded on healthiness in adolescence.

Restricted access

Kenneth W. Kambis and Sarah K. Pizzedaz

Creatine monohydrate (CrH2O) supplementation has been demonstrated to increase skeletal muscle power output in men. However, its effect upon women is not as clearly defined. This study investigated the effect of oral creatine supplementation upon muscle function, thigh circumference, and body weight in women. Twenty-two consenting college-age women were assigned to 1 of 2 groups matched for dietary and exercise habits, phase of menstrual cycle, and fat-free mass (FFM). After familiarization with testing procedures, pretrial measures of muscle function (5 repetitions 60 deg · s−1 and 50 repetitions 180 deg · s−1) were conducted during maximal voluntary concentric contraction of the preferred quadriceps muscle using an isokinetic dynamometer. Subjects then ingested 0.5 g · kg−1 FFM of either CrH2O or placebo (one fourth dosage 4 times daily) in a double-blind design for 5 days. Resistance exercise was prohibited. After the ingestion phase was completed, all measures were repeated at the same time of day as during pretrials. Statistical analysis revealed time to peak torque in quadriceps extension decreased from pre-test values of 255 ± 11 ms (mean ± SEM) to post-test values of 223 ± 3 ms; average power in extension increased from 103 ± 7 W pre-test to 112 ± 7 W post-test; and, during flexion, average power increased from 59 ± 5 W pre-test to 65 ± 5 W post-test in the creatine group as compared to controls (p ≤ .05). FFM, percent body fat, mid-quadriceps circumference, skinfold thickness of the measured thigh, and total body weight did not change for both groups between trials. We conclude that CrH2O improves muscle performance in women without significant gains in muscle volume or body weight.

Restricted access

Erin Calaine Inglis, Danilo Iannetta, Louis Passfield and Juan M. Murias

, the boundary separating tolerable and nontolerable exercise) and is often identified by measures including the maximal lactate steady state (MLSS) or critical power (CP). 3 Although the accuracy for determining this intensity is best obtained in a laboratory setting, this is not always feasible due to cost

Restricted access

Anna Bjerkefors, Johanna S. Rosén, Olga Tarassova and Anton Arndt

to an increase in pelvis and trunk rotation and a higher power output. 1 Kayaking performed by people with physical impairment is called para-kayak and was introduced as an international competitive sport in 2009 and debuted in the Paralympic Games in 2016. In Paralympic sports, athletes compete in