Purpose: The 2-bout exercise protocol has been developed to diagnose nonfunctional overreaching and the “overtraining syndrome.” It consists of 2 maximal exercise bouts separated by 4 hours. Mental fatigue negatively influences performance, but the effects of its occurrence during the 2-bout exercise protocol have never been investigated. The aim of this study was to examine whether mental fatigue (induced during the rest period) influences physical and cognitive performance during/after the second exercise bout of the 2-bout exercise protocol. Methods: Nine healthy, well-trained male cyclists participated in a single-blind, randomized, placebo-controlled crossover study. The intervention consisted of either 1.5-hour rest (control) or performing a computer-based Stroop task to induce mental fatigue. Cognitive (Eriksen Flanker task), physiological (lactate, maximum heart rate, and maximum wattage), and subjective data (mental fatigue-visual analog scale, Profile of Mood States, and rating of perceived exertion) were gathered. Results: Ratings of fatigue, tension, and mental fatigue were affected in the mental fatigue condition (P < .05). Neither physiological nor cognitive differences were found between conditions. Ratings of mental fatigue were already affected after the first maximum exercise test (P < .05). Conclusions: Neither physical nor cognitive performance was affected by mental fatigue, but subjective ratings did reveal significant differences. It is recommended to exclude mentally challenging tasks during the 2-bout exercise protocol rest period to ascertain unaffected subjective test results. This study should be repeated in athletes diagnosed with nonfunctional overreaching/overtraining syndrome.
Susan Vrijkotte, Romain Meeusen, Cloe Vandervaeren, Luk Buyse, Jeroen van Cutsem, Nathalie Pattyn and Bart Roelands
Sabrina Skorski, Iñigo Mujika, Laurent Bosquet, Romain Meeusen, Aaron J. Coutts and Tim Meyer
Physiological and psychological demands during training and competition generate fatigue and reduce an athlete’s sport-specific performance capacity. The magnitude of this decrement depends on several characteristics of the exercise stimulus (eg, type, duration, and intensity), as well as on individual characteristics (eg, fitness, profile, and fatigue resistance). As such, the time required to fully recover is proportional to the level of fatigue, and the consequences of exercise-induced fatigue are manifold. Whatever the purpose of the ensuing exercise session (ie, training or competition), it is crucial to understand the importance of optimizing the period between exercise bouts in order to speed up the regenerative processes and facilitate recovery or set the next stimulus at the optimal time point. This implies having a fairly precise understanding of the fatigue mechanisms that contribute to the performance decrement. Failing to respect an athlete’s recovery needs may lead to an excessive accumulation of fatigue and potentially “nonfunctional overreaching” or to maladaptive training. Although research in this area recently increased, considerations regarding the specific time frames for different physiological mechanisms in relation to exercise-induced fatigue are still missing. Furthermore, recommendations on the timing and dosing of recovery based on these time frames are limited. Therefore, the aim of this article is to describe time courses of recovery in relation to the exercise type and on different physiological levels. This summary supports coaches, athletes, and scientists in their decision-making process by considering the relationship of exercise type, physiology, and recovery.
Inne Aerts, Elke Cumps, Evert Verhagen, Bram Wuyts, Sam Van De Gucht and Romain Meeusen
In jump-landing sports, the injury mechanism that most frequently results in an injury is the jump-landing movement. Influencing the movement patterns and biomechanical predisposing factors are supposed to decrease injury occurrence.
To evaluate the influence of a 3-mo coach-supervised jump-landing prevention program on jump-landing technique using the jump-landing scoring (JLS) system.
Randomized controlled trial.
116 athletes age 15–41 y, with 63 athletes in the control group and 53 athletes in the intervention group. Intervention: The intervention program in this randomized control trial was administered at the start of the basketball season 2010–11. The jump-landing training program, supervised by the athletic trainers, was performed for a period of 3 mo.
Main Outcome Measures:
The jump-landing technique was determined by registering the jump-landing technique of all athletes with the JLS system, pre- and postintervention.
After the prevention program, the athletes of the male and female intervention groups landed with a significantly less erect position than those in the control groups (P < .05). This was presented by a significant improvement in maximal hip flexion, maximal knee flexion, hip active range of motion, and knee active range of motion. Another important finding was that postintervention, knee valgus during landing diminished significantly (P < .05) in the female intervention group compared with their control group. Furthermore, the male intervention group significantly improved (P < .05) the scores of the JLS system from pre- to postintervention.
Malalignments such as valgus position and insufficient knee flexion and hip flexion, previously identified as possible risk factors for lower-extremity injuries, improved significantly after the completion of the prevention program. The JLS system can help in identifying these malalignments.
Level of Evidence:
Therapy, prevention, level 1b.
Anissa Cherif, Romain Meeusen, Abdulaziz Farooq, Joong Ryu, Mohamed Amine Fenneni, Zoran Nikolovski, Sittana Elshafie, Karim Chamari and Bart Roelands
To examine the effects of 3 d of intermittent fasting (3d-IF: abstaining from eating/drinking from dawn to sunset) on physical performance and metabolic responses to repeated sprints (RSs).
Twenty-one active males performed an RS test (2 sets: 5 × 5-s maximal sprints with 25 s of recovery between and 3 min of recovery between sets on an instrumented treadmill) in 2 conditions: counterbalanced fed/control session (CS) and fasting session (FS). Biomechanical and biochemical markers were assessed preexercise and postexercise.
Significant main effects of IF were observed for sprints: maximal speed (P = .016), mean speed (P = .015), maximal power (P = .035), mean power (P = .049), vertical stiffness (P = .032), and vertical center-of-mass displacement (P = .047). Sprint speed and vertical stiffness decreased during the 1st (P = .003 and P = .005) and 2nd sprints (P = .046 and P = .048) of set 2, respectively. Postexercise insulin decreased in CS (P = .023) but not in FS (P = .230). Free-fatty-acid levels were higher in FS than in CS at preexercise (P < .001) and at postexercise (P = .009). High-density lipoprotein cholesterol (HDL-C) was higher at postexercise in FS (1.32 ± 0.22 mmol/L) than in CS (1.26 ± 0.21 mmol/L, P = .039). The triglyceride (TG) concentration was decreased in FS (P < .05) compared with CS.
3d-IF impaired speed and power through a decrease in vertical stiffness during the initial runs of the 2nd set of RS. The findings of the current study confirmed the benefits of 3d-IF: improved HDL-C and TG profiles while maintaining total cholesterol and low-density lipoprotein cholesterol levels. Moreover, improving muscle power might be a key factor to retain a higher vertical stiffness and to partly counteract the negative effects of intermittent fasting.
Tine Torbeyns, Bas de Geus, Stephen Bailey, Lieselot Decroix, Jeroen Van Cutsem, Kevin De Pauw and Romain Meeusen
Physical activity is positively associated with physical health, cognitive performance, brain functioning and academic performance. The aim of this study is to investigate the influence of bike desks in the classroom on adolescents’ energy expenditure, physical health, cognitive performance, brain functioning and academic performance.
Forty-four adolescents were randomly assigned to control group (CG) or intervention group (IG). During 5 months, the IG used a bike desk for 4 class hours/week. Energy expenditure was measured during 6 consecutive days. Anthropometric parameters, aerobic fitness, academic performance, cognitive performance and brain functioning were assessed before (T0) and after (T1) the intervention.
Energy expenditure of the IG was significantly higher during the class hours in which they used the bike desks relative to normal class hours. The CG had a significantly higher BMI at T1 relative to T0 while this was not significantly different for the IG. Aerobic fitness was significantly better in the IG at T1 relative to T0. No significant effects on academic performance cognitive performance and brain functioning were observed.
As the implementation of bike desks in the classroom did not interfere with adolescents’ academic performance, this can be seen as an effective means of reducing in-class sedentary time and improving adolescents’ physical health.
Maria Francesca Piacentini, Oliver C. Witard, Cajsa Tonoli, Sarah R. Jackman, James E. Turner, Arie K. Kies, Asker E. Jeukendrup, Kevin D. Tipton and Romain Meeusen
Monitoring mood state is a useful tool for avoiding nonfunctional overreaching. Brain-derived neurotrophic factor (BDNF) is implicated in stress-related mood disorders.
To investigate the impact of intensified training-induced mood disturbance on plasma BDNF concentrations at rest and in response to exercise.
Eight cyclists performed 1 wk of normal (NT), 1 wk of intensified (INT), and 1 wk of recovery (REC) training. Fasted blood samples were collected before and after exercise on day 7 of each training week and analyzed for plasma BDNF and cortisol concentrations. A 24-item Profile of Mood State questionnaire was administered on day 7 of each training week, and global mood score (GMS) was calculated.
Time-trial performance was impaired during INT (P = .01) and REC (P = .02) compared with NT. Basal plasma cortisol (NT = 153 ± 16 ng/mL, INT = 130 ± 11 ng/mL, REC = 150 ± 14 ng/ml) and BDNF (NT = 484 ± 122 pg/mL, INT = 488 ± 122 pg/mL, REC = 383 ± 56 pg/mL) concentrations were similar between training conditions. Likewise, similar exercise-induced increases in cortisol and BDNF concentrations were observed between training conditions. GMS was 32% greater during INT vs NT (P < .001).
Consistent with a state of functional overreaching (FOR), impairments in performance and mood state with INT were restored after 1 wk of REC. These results support evidence for mood changes before plasma BDNF concentrations as a biochemical marker of FOR and that cortisol is not a useful marker for predicting FOR.
Kevin De Pauw, Bart Roelands, Jeroen Van Cutsem, Lieselot Decroix, Angelica Valente, Kim Taehee, Robert B. Lettan II, Andres E. Carrillo and Romain Meeusen
Nasal spray (NAS) containing caffeine (CAF) or glucose (GLUC) activates sensory(motor) cortices.
To investigate the influence of CAF or GLUC NAS on exercise and cognitive performance.
Eleven male subjects (age 22 ± 2 y) performed a maximal cycle test and 2 familiarization and 3 experimental trials. Each trial included a 30-s Wingate test and a 30-min time-trial (TT) performance test interspersed by 15 min of rest. Before and after each exercise test a Stroop task was conducted. Placebo NAS with or without CAF or GLUC was provided before each exercise session and at each completed 25% of the TT. Exercise-performance, physiological, and cognitive measures were obtained. Magnitude-based inferences determined the likelihood that NAS solutions would be beneficial, trivial, or negative to exercise-performance measures based on the smallest worthwhile effect. Physiological and cognitive measures were analyzed using (non)parametric tests (P < .05).
GLUC NAS substantially increased the average power output during the TT (very likely beneficial: 98%). No further worthwhile exercise-performance enhancements were found for both substances. In addition, no significant differences in physiological and cognitive measures were observed. In line with mouth rinsing, GLUC was shown to substantially enhance endurance performance, probably due to the activation of the olfactory pathway and/or extra-oral sweet-taste receptors.
GLUC NAS enhances endurance performance, which indicates a novel administration route. The higher activity in sensory brain cortices probably elicited the ergogenic effect. However, no further physiological and cognitive changes occurred, indicating that higher doses of substrates might be required.
Twan ten Haaf, Selma van Staveren, Erik Oudenhoven, Maria F. Piacentini, Romain Meeusen, Bart Roelands, Leo Koenderman, Hein A.M. Daanen, Carl Foster and Jos J. de Koning
To investigate whether monitoring of easily measurable stressors and symptoms can be used to distinguish early between acute fatigue (AF) and functional overreaching (FOR).
The study included 30 subjects (11 female, 19 male; age 40.8 ± 10.8 y, VO2max 51.8 ± 6.3 mL · kg–1 · min–1) who participated in an 8-d cycling event over 1300 km with 18,500 climbing meters. Performance was measured before and after the event using a maximal incremental test. Subjects with decreased performance after the event were classified as FOR, others as AF. Mental and physical well-being, internal training load, resting heart rate, temperature, and mood were measured daily during the event. Differences between AF and FOR were analyzed using mixed-model ANOVAs. Logistic regression was used to determine the best predictors of FOR after 3 and 6 d of cycling.
Fifteen subjects were classified as FOR and 14 as AF (1 excluded). Although total group changes were observed during the event, no differences between AF and FOR were found for individual monitoring parameters. The combination of questionnaire-based changes in fatigue and readiness to train after 3 d cycling correctly predicted 78% of the subjects as AF or FOR (sensitivity = 79%, specificity = 77%).
Monitoring changes in fatigue and readiness to train, using simple visual analog scales, can be used to identify subjects likely to become FOR after only 3 d of cycling. Hence, we encourage athlete support staff to monitor not only fatigue but also the subjective integrated mental and physical readiness to perform.
Bas de Geus, Bart Degraeuwe, Grégory Vandenbulcke, Luc Int Panis, Isabelle Thomas, Joris Aertsens, Yves De Weerdt, Rudi Torfs and Romain Meeusen
For an accurate estimation of health benefits and hazards of utilitarian cycling, a prospective collection of bicycle usage data (exposure) is fundamental. Individual and environmental correlates are necessary to guide health promotion and traffic safety issues. Firstly, this study aims to report on utilitarian bicycle usage in Belgium, using a prospective data collection in regular adult commuter cyclists. Secondly, the association is explored between the individual variation in bicycle usage and individual and environmental correlates.
1187 regular adult cyclists filled out travel diaries prospectively. Multivariate linear regression with Stepwise selection (SMLR) models studied the association between exposure and individual and environmental correlates.
Higher age and availability of cycle paths have a positive association with bicycle usage to work. Women cycle significant less compared with men, and so do cyclists with ‘poor’ or ‘average’ health. Living in an urban crown (opposed to city center) and living in Flanders (opposed to Brussels or Wallonia) is associated with significantly more cycling.
Utilitarian cycling is related to regional differences, level of urbanization of the place of residence, availability of bicycle paths, and gender. These findings are useful in estimating health benefits and hazards of utilitarian cycling among regular Belgian cyclists.
Twan ten Haaf, Selma van Staveren, Danilo Iannetta, Bart Roelands, Romain Meeusen, Maria F. Piacentini, Carl Foster, Leo Koenderman, Hein A.M. Daanen and Jos J. de Koning
Purpose: Reaction time has been proposed as a training monitoring tool, but to date, results are equivocal. Therefore, it was investigated whether reaction time can be used as a monitoring tool to establish overreaching. Methods: The study included 30 subjects (11 females and 19 males, age: 40.8 [10.8] years, VO2max: 51.8 [6.3] mL/kg/min) who participated in an 8-day cycling event. The external exercise load increased approximately 900% compared with the preparation period. Performance was measured before and after the event using a maximal incremental cycling test. Subjects with decreased performance after the event were classified as functionally overreached (FOR) and others as acutely fatigued (AF). A choice reaction time test was performed 2 weeks before (pre), 1 week after (post), and 5 weeks after (follow-up), as well as at the start and end of the event. Results: A total of 14 subjects were classified as AF and 14 as FOR (2 subjects were excluded). During the event, reaction time at the end was 68 ms (95% confidence interval, 46–89) faster than at the start. Reaction time post event was 41 ms (95% confidence interval, 12–71) faster than pre event and follow-up was 55 ms faster (95% confidence interval, 26–83). The time by class interaction was not significant during (P = .26) and after (P = .43) the event. Correlations between physical performance and reaction time were not significant (all Ps > .30). Conclusions: No differences in choice reaction time between AF and FOR subjects were observed. It is suggested that choice reaction time is not valid for early detection of overreaching in the field.