longer. 1 NFO and OTS are the result of a disbalance between training and recovery. Both psychological and physiological factors interact to create distress that can result in physical and mental fatigue. 2 Meeusen et al 1 , 3 developed a 2-bout exercise protocol for diagnosing NFO and OTS. The 2-bout
Susan Vrijkotte, Romain Meeusen, Cloe Vandervaeren, Luk Buyse, Jeroen van Cutsem, Nathalie Pattyn and Bart Roelands
Mathias H. Kosack, Walter Staiano, Rasmus Folino, Mads B. Hansen and Simon Lønbro
Mental fatigue (MF) is defined as a psychobiological state caused by a demanding cognitive activity. 1 MF expresses itself in various ways and is associated with an increased risk of error and slower reaction time during simple cognitive tasks (ie, time on task, go/no-go task) 2 , 3 and has been
Luca Filipas, Davide Ferioli, Giuseppe Banfi, Antonio La Torre and Jacopo Antonino Vitale
of acute SR on technical performance in basketball. Acute mental fatigue (MF) is defined as a psychobiological state that may arise during or after prolonged cognitive activities; it is characterized by feelings of tiredness or even exhaustion, and a decreased commitment and increased aversion to
Oliver O. Badin, Mitchell R. Smith, Daniele Conte and Aaron J. Coutts
To assess the effects of mental fatigue on physical and technical performance in small-sided soccer games.
Twenty soccer players (age 17.8 ± 1.0 y, height 179 ± 5 cm, body mass 72.4 ± 6.8 kg, playing experience 8.3 ± 1.4 y) from an Australian National Premier League soccer club volunteered to participate in this randomized crossover investigation. Participants played 15-min 5-vs-5 small-sided games (SSGs) without goalkeepers on 2 occasions separated by 1 wk. Before the SSG, 1 team watched a 30-min emotionally neutral documentary (control), while the other performed 30 min of a computer-based Stroop task (mental fatigue). Subjective ratings of mental and physical fatigue were recorded before and after treatment and after the SSG. Motivation was assessed before treatment and SSG; mental effort was assessed after treatment and SSG. Player activity profiles and heart rate (HR) were measured throughout the SSG, whereas ratings of perceived exertion (RPEs) were recorded before the SSG and immediately after each half. Video recordings of the SSG allowed for notational analysis of technical variables.
Subjective ratings of mental fatigue and effort were higher after the Stroop task, whereas motivation for the upcoming SSG was similar between conditions. HR during the SSG was possibly higher in the control condition, whereas RPE was likely higher in the mental-fatigue condition. Mental fatigue had an unclear effect on most physical-performance variables but impaired most technical-performance variables.
Mental fatigue impairs technical but not physical performance in small-sided soccer games.
Manuel D. Quinones and Peter W.R. Lemon
Hydrothermally modified non-genetically modified organisms corn starch (HMS) ingestion may enhance endurance exercise performance via sparing carbohydrate oxidation. To determine whether similar effects occur with high-intensity intermittent exercise, we investigated the effects of HMS ingestion prior to and at halftime on soccer skill performance and repeated sprint ability during the later stages of a simulated soccer match. In total, 11 male university varsity soccer players (height = 177.7 ± 6.8 cm, body mass = 77.3 ± 7.9 kg, age = 22 ± 3 years, body fat = 12.8 ± 4.9%, and maximal oxygen uptake = 57.1 ± 3.9 ml·kg BM−1·min−1) completed the match with HMS (8% carbohydrate containing a total of 0.7 g·kg BM−1·hr−1; 2.8 kcal·kg BM−1·hr−1) or isoenergetic dextrose. Blood glucose was lower (p < .001) with HMS at 15 min (5.3 vs. 7.7 mmol/L) and 30 min (5.6 vs. 8.3 mmol/L) following ingestion, there were no treatment differences in blood lactate, and the respiratory exchange ratio was lower with HMS at 15 min (0.84 vs. 0.86, p = .003); 30 min (0.83 vs. 0.85, p = .004); and 45 min (0.83 vs. 0.85, p = .007) of the first half. Repeated sprint performance was similar for both treatments (p > .05). Soccer dribbling time was slower with isoenergetic dextrose versus baseline (15.63 vs. 14.43 s, p < .05) but not so with HMS (15.04 vs. 14.43 s, p > .05). Furthermore, during the passing test, penalty time was reduced (4.27 vs. 7.73 s, p = .004) with HMS. During situations where glycogen availability is expected to become limiting, HMS ingestion prematch and at halftime could attenuate the decline in skill performance often seen late in contests.
Nils Haller, Tobias Ehlert, Sebastian Schmidt, David Ochmann, Björn Sterzing, Franz Grus and Perikles Simon
assessed by a visual analog scale (VAS) questionnaire, which included football-specific items such as general perceived exertion, muscular, and mental fatigue. Rate of perceived exertion (RPE)–based methods have been suggested as a reliable tool for player load in previous studies. 17 Moreover, acute
Thomas B. Walker and Robert A. Robergs
Rhodiola rosea is an herb purported to possess adaptogenic and ergogenic properties and has recently been the subject of increased interest. The purpose of this article was to review and summarize recent investigations of the potential performance-enhancing properties of Rhodiola rosea. Such studies have generated equivocal results. Several investigations conducted in Eastern Europe have indicated that Rhodiola rosea ingestion may produce such positive effects as improved cognitive function and reduced mental fatigue. Other research from this region has illustrated enhanced endurance exercise performance in both humans and rats. Studies conducted in Western Europe and in North America have indicated that Rhodiola rosea may possess substantial antioxidant properties but have produced mixed results when attempting to demonstrate an ergogenic effect during exercise in humans.
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.
Ed Maunder, Andrew E. Kilding and Simeon P. Cairns
The manifestations of fatigue during fast bowling in cricket were systematically evaluated using subjective reports by cricket experts and quantitative data published from scientific studies. Narratives by international players and team physiotherapists were sourced from the Internet using criteria for opinion-based evidence. Research articles were evaluated for high-level fast bowlers who delivered 5- to 12-over spells with at least 1 quantitative fatigue measure. Anecdotes indicate that a long-term loss of bowling speed, tiredness, mental fatigue, and soreness occur. Scientific research shows that ball-release speed, bowling accuracy, bowling action (technique), run-up speed, and leg-muscle power are generally well maintained during bowling simulations. However, bowlers displaying excessive shoulder counterrotation toward the end of a spell also show a fall in accuracy. A single notable study involving bowling on 2 successive days in the heat showed reduced ball-release speed (–4.4 km/h), run-up speed (–1.3 km/h), and accuracy. Moderate to high ratings of perceived exertion transpire with simulations and match play (6.5–7.5 Borg CR-10 scale). Changes of blood lactate, pH, glucose, and core temperature appear insufficient to impair muscle function, although several potential physiological fatigue factors have not been investigated. The limited empirical evidence for bowling-induced fatigue appears to oppose player viewpoints and indicates a paradox. However, this may not be the case since bowling simulations resemble the shorter formats of the game but not multiday (test match) cricket or the influence of an arduous season, and comments of tiredness, mental fatigue, and soreness signify phenomena different from what scientists measure as fatigue.
Israel Halperin, David B. Pyne and David T. Martin
Internal validity refers to the degree of control exerted over potential confounding variables to reduce alternative explanations for the effects of various treatments. In exercise and sports-science research and routine testing, internal validity is commonly achieved by controlling variables such as exercise and warm-up protocols, prior training, nutritional intake before testing, ambient temperature, time of testing, hours of sleep, age, and gender. However, a number of other potential confounding variables often do not receive adequate attention in sports physiology and performance research. These confounding variables include instructions on how to perform the test, volume and frequency of verbal encouragement, knowledge of exercise endpoint, number and gender of observers in the room, influence of music played before and during testing, and the effects of mental fatigue on performance. In this review the authors discuss these variables in relation to common testing environments in exercise and sports science and present some recommendations with the goal of reducing possible threats to internal validity.