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Clare MacMahon, Linda Schücker, Norbert Hagemann and Bernd Strauss

This study investigated the effect of cognitive fatigue on physical performance in a paced running task. Experienced runners (n = 20) performed two 3,000-m runs on an indoor track, once after cognitive fatigue, and once under nonfatigued conditions. Completion times were significantly slower in the cognitive fatigue condition (M = 12:11,88 min, SD = 0:54,26), compared with the control condition (M = 11:58,56 min, SD = 0:48,39), F(1, 19) = 8.58, p = .009, eta2p = .31. There were no differences in heart rate, t(17) = 0.13, p > .05, blood lactate levels, t(19) = 1.19, p > .05, or ratings of perceived exertion F(1, 19) = .001, p 3 .05. While previous research has examined the impact of cognitive tasks on physical tasks, this is the first study to examine a self-paced physical task, showing that cognitive activity indeed contributes significantly to overall performance. Specifically, cognitive fatigue increased the perception of exertion, leading to lesser performance on the running task.

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Darren J. Paul, Paul S. Bradley and George P. Nassis

Time-motion analysis is a valuable data-collection technique used to quantify the match running performance of elite soccer players. However, interpreting the reductions in running performance in the 2nd half or temporarily after the most intense period of games is highly complex, as it could be attributed to physical or mental fatigue, pacing strategies, contextual factors, or a combination of mutually inclusive factors. Given that research in this domain typically uses a reductionist approach whereby match running performance is examined in isolation without integrating other factors, this ultimately leads to a 1-dimensional insight into match performance. Subsequently, a cohesive review of influencing factors does not yet exist. The aim of this commentary is to provide a detailed insight into the complexity of match running performance and its most influential factors.

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Maxime Deshayes, Corentin Clément-Guillotin and Raphaël Zory

of sex stereotype induction on physical performance for a task that does not require technical skill. We used an endurance task that can be encountered in daily life: a self-paced cycling task. In addition to recording power output during the cycling task, challenge appraisals were also investigated

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Pål Haugnes, Per-Øyvind Torvik, Gertjan Ettema, Jan Kocbach and Øyvind Sandbakk

’s pacing before entering the finish sprint leads to various degrees of fatigue. Due to the competition format in XC skiing sprint, the pacing utilized during heats and thereby the subsequent grade of fatigue at the finish sprint is decided both by each athlete’s choice of effort and the competition speed

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Stuart J. Cormack, Mitchell G. Mooney, Will Morgan and Michael R. McGuigan

Purpose:

To determine the impact of neuromuscular fatigue (NMF) assessed from variables obtained during a countermovement jump on exercise intensity measured with triaxial accelerometers (load per minute [LPM]) and the association between LPM and measures of running activity in elite Australian Football.

Methods:

Seventeen elite Australian Football players performed the Yo-Yo Intermittent Recovery Test level 2 (Yo-Yo IR2) and provided a baseline measure of NMF (flight time:contraction time [FT:CT]) from a countermovement jump before the season. Weekly samples of FT:CT, coaches’ rating of performance (votes), LPM, and percent contribution of the 3 vectors from the accelerometers in addition to high-speed-running meters per minute at >15 km/h and total distance relative to playing time (m/min) from matches were collected. Samples were divided into fatigued and nonfatigued groups based on reductions in FT:CT. Percent contributions of vectors to LPM were assessed to determine the likelihood of a meaningful difference between fatigued and nonfatigued groups. Pearson correlations were calculated to determine relationships between accelerometer vectors and running variables, votes, and Yo-Yo IR2 score.

Results:

Fatigue reduced the contribution of the vertical vector by (mean ± 90% CI) –5.8% ± 6.1% (86% likely) and the number of practically important correlations.

Conclusions:

NMF affects the contribution of individual vectors to total LPM, with a likely tendency toward more running at low speed and less acceleration. Fatigue appears to limit the influence of the aerobic and anaerobic qualities assessed via the Yo-Yo IR2 test on LPM and seems implicated in pacing.

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Arturo Casado and Andrew Renfree

several studies have investigated pacing strategies in middle-distance (800 and 1500 m) running events, assessed through distribution of speeds over race segments, 2 – 4 other work has examined the influence of tactical positioning at intermediate points on finishing position. 5 Tactical issues are

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Margina Ruiter, Charly Eielts, Sofie Loyens and Fred Paas

seated rest and self-paced cycling on a desk bike in preadolescent children. The present study included several cognitive tests measuring cognitive control (ie, inhibition, visuospatial, and verbal working memory). On the basis of previous literature, it was expected that cognitive control was unaffected

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Roger Eston

The rating of perceived exertion (RPE) is a recognized marker of intensity and of homeostatic disturbance during exercise. It is typically monitored during exercise tests to complement other measures of intensity. The purpose of this commentary is to highlight the remarkable value of RPE as a psychophysiological integrator in adults. It can be used in such diverse fashions as to predict exercise capacity, assess changes in training status, and explain changes in pace and pacing strategy. In addition to using RPE to self-regulate exercise, a novel application of the intensity:RPE relationship is to clamp RPE at various levels to produce self-paced bouts of exercise, which can be used to assess maximal functional capacity. Research also shows that the rate of increase in RPE during self-paced competitive events of varying distance, or constant-load tasks where the participant exercises until volitional exhaustion, is proportional to the duration that remains. These findings suggest that the brain regulates RPE and performance in an anticipatory manner based on awareness of metabolic reserves at the start of an event and certainty of the anticipated end point. Changes in pace may be explained by a continuous internal negotiation of momentary RPE compared with a preplanned “ideal rate of RPE progression” template, which takes into account the portion of distance covered and the anticipated end point. These observations have led to the development of new techniques to analyze the complex relationship of RPE and pacing. The use of techniques to assess frontal-cortex activity will lead to further advances in understanding.

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James J. McClain, Gregory J. Welk, Michelle Ihmels and Jodee Schaben

Background:

The PACER test is a valid and reliable assessment of aerobic capacity in children. However, many schools lack adequate space to administer the test. This study compared the utility of the standard 20m PACER test with an alternative 15m PACER protocol in 5th and 8th grade students.

Methods:

A total of 171 students completed both PACER protocols in a counterbalanced design. Agreement between the two protocols was assessed with correlations, repeated-measures ANOVA, and classification agreement into the FITNESSGRAM ® healthy fitness zones.

Results:

The difference in estimated VO2max between the two tests was slightly larger for boys (5th grade, 1.32 ml/kg/min; 8th grade, 1.72 ml/kg/min) than girls (5th grade, 0.14 ml/kg/min; 8th grade, 1.11 ml/kg/min), but these differences are probably not of practical significance. Classification agreement was 88% for boys and 91% for girls.

Conclusions:

Collectively, the results suggest that the 15m and 20m PACER provide similar information about aerobic fitness in youth. The 20m test is recommended when possible, but the 15m provides a useful alternative for schools with smaller gymnasiums.

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Cyril Schmit, Rob Duffield, Christophe Hausswirth, Aaron J. Coutts and Yann Le Meur

Purpose:

To describe the effect of the initial perceptual experience from heat familiarization on the pacing profile during a freepaced endurance time trial (TT) compared with temperate conditions.

Methods:

Two groups of well-trained triathletes performed two 20-km TTs in either hot (35°C and 50% relative humidity [RH], n = 12) or temperate (21°C and 50% RH, n = 22) conditions, after standardization of training for each group before both trials. To ensure no physiological acclimation differences between conditions, the TTs for both groups were separated by 11 ± 4 d.

Results:

Performance improvement in the heat (11 ± 24 W) from the 1st to 2nd trial appeared comparable to that in temperate conditions (8 ± 14 W, P = .67). However, the specific alteration in pacing profile in the heat was markedly different than temperate conditions, with a change from “positive” to an “even” pacing strategy.

Conclusions:

Altered perceptions of heat during heat familiarization, rather than physiological acclimatization per se, may mediate initial changes in pacing and TT performance in the heat. These results highlight the need for athletes without time for sufficient heat acclimatization to familiarize themselves with hot conditions to reduce the uncertainty from behavior-based outcomes that may impede performance.