Mental fatigue and exercise performance

An investigation of cognitive task engagement and subsequent muscular endurance performance and brain endurance training (BET) - increased cognitive demand during physical training. Chapter two utilised a triple task (cognitive–physical–cognitive) to investigate the dose-response of a response inhibition task on submaximal handgrip. Handgrip was impaired following cognitive tasks of 10 minutes but not after 5 and 20 minutes. Learning effects occurred during the 20 minute cognitive task. A prior response inhibition task improved performance in a novel response inhibition task. These results can be explained by cognitive control theory. Chapter three demonstrated that engagement in a mentally demanding cognitive task, without response inhibition, for a period of 20 minutes did not impair submaximal isometric handgrip exercise. Chapter four investigated temporal effect of mental fatigue with 4 blocks of 10 minutes cognitive task followed by 5 minutes of rhythmic handgrip. Over time indices of mental fatigue diverge, with self-report measures accentuating and physiological measures attenuating. After 20 minutes this state of mental fatigue impaired physical performance. Chapter five demonstrated that 6 weeks BET alongside submaximal handgrip training, increased endurance performance by 32%, which occurred with a higher prefrontal cortex oxygenation, relative to 12% improvements in control

Movement profile monitoring in professional football

Introduction: Professional football clubs are increasing monitoring players movements in training and competition to quantify total training load. Semi-automated motion camera tracking (MCT) is used in competition and global positioning satellite (GPS) in training. GPS also transmit data in real time (RT). To use data from the systems interchangeably the level and direction of agreement needs to be quantified. Experiment one: The comparison of a GPS data in RT to post session (PS). Over three competitive matches players were monitored in RT and data compared with PS. All external parameters were significantly different from RT to PS and all internal parameters showed no difference. Care should be used if basing training session benchmarks of external PS data and applying in RT. Experiment two: The comparison of an MCT and GPS systems data and an investigation into the validity of each system to report distance covered in the highest speed zone. GPS significantly under reported distance covered at all velocities compared to MCT. MCT over reported (170%) entries into the highest speed zone and GPS under (39%). Discussion: Data from the two types of system can currently not be used interchangeably and RT monitoring is not accurate relative to PS data

Effects of isolated and combined mental and physical fatigue on motor skill and endurance exercise performance

BackgroundMental fatigue, elicited by cognitive demands, can impair sport and exercise performance. The effects of isolated mental fatigue on performance are well documented but few studies have explored the effects of combined mental and physical fatigue on skilled motor and endurance exercise performance.ObjectiveThis study explored the effects of isolated mental, isolated physical, and combined (mental plus physical) fatigue on skill and exercise task performance.Method164 athletes were randomly assigned to 1 of 4 groups: mental fatigue, physical fatigue, combined fatigue, control (no fatigue). Mental fatigue was induced by a 15-min time-load dual-back cognitive task. Physical fatigue was induced by a 90-s burpee exercise task. Next, all participants completed a throwing skill task and performed burpee exercises to failure. Objective (brief Psychomotor Vigilance Task, PVT-B) and subjective (self-report) measures of mental fatigue and Ratings of Perceived Exertion were obtained throughout.ResultsThe mental fatigue and combined fatigue groups performed the worst on both the throwing and burpee tasks compared with the physical fatigue and control groups. The former reported higher mental fatigue throughout and had worse response accuracy and variation on the end-of-session PVT-B task. The combined fatigue group performed better than the mental fatigue group on the throwing and burpee tasks.ConclusionA demanding cognitive task induced a state of mental fatigue and impaired skill and endurance performance. Mental fatigue alone was more detrimental than combined fatigue to skill and endurance performance, suggesting that the physical activity manipulation reduced the negative effects of mental fatigue on performance