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The purpose of this study was firstly to examine the sensitivity of heart rate (HR)‐based and subjective monitoring markers to intensified endurance training; and secondly, to investigate the validity of these markers to distinguish individuals in different fatigue states. A total of 24 recreational runners performed a 3‐week baseline period, a 2‐week overload period, and a 1‐week recovery period. Performance was assessed before and after each period with a 3000m running test. Recovery was monitored with daily orthostatic tests, nocturnal HR recordings, questionnaires, and exercise data. The participants were divided into subgroups (overreached/OR, n = 8; responders/RESP, n = 12) based on the changes in performance and subjective recovery. The responses to the second week of the overload period were compared between the subgroups. RESP improved their baseline 3000 m time (p < 0.001) after the overload period (−2.5 ± 1.0%), and the change differed (p < 0.001) from OR (0.6 ± 1.2%). The changes in nocturnal HR (OR 3.2 ± 3.1%; RESP −2.8 ± 3.7%, p = 0.002) and HR variability (OR −0.7 ± 1.8%; RESP 2.1 ± 1.6%, p = 0.011) differed between the subgroups. In addition, the decrease in subjective readiness to train (p = 0.009) and increase in soreness of the legs (p = 0.04) were greater in OR compared to RESP. Nocturnal HR, readiness to train, and exercise‐derived HR‐running power index had ≥85% positive and negative predictive values in the discrimination between OR and RESP individuals. In conclusion, exercise tolerance can vary substantially in recreational runners. The results supported the usefulness of nocturnal HR and subjective recovery assessments in recognizing fatigue states. Highlights: Tolerance to similarly increased training load varies in recreational runners. While some individuals respond positively, for others the same load may be excessive.Subjective markers, such as readiness to train and soreness of the legs, were the most sensitive markers to respond to increased training load, and the magnitude of these responses was greater in individuals with suspected overreaching.Resting or exercise heart rate (HR) did not respond as systematically as the subjective markers to the training load itself. However, the changes in nocturnal HR, nocturnal HRV, and HR‐running power index started to differ between the RESP and OR subgroups at an earlier stage of the overload period supporting their usefulness as indicators of the fatigue state. [ABSTRACT FROM AUTHOR]

While the interest and professionalization of padel around the world, and the importance of mental fatigue in sport science literature are both on the rise, not much is known about how mental fatigue impacts padel‐specific performance. Forty‐eight male elite youth players (18 ± 2 y) participated in this randomized counterbalanced crossover study. The players visited the laboratory on three separate occasions: familiarization, control (i.e., 30‐min documentary), and mental fatigue (i.e., 30‐min incongruent Stroop) condition. The participants' perceived mental fatigue, vigilance (i.e., Psychomotor Vigilance Test) and response inhibition (i.e., Stroop task) were assessed as markers of mental fatigue. The Padel accuracy was evaluated using a validated padel‐specific performance task that includes the usage of different strokes (i.e., drive, drive volley, bandeja, and drive attack after the use of the glass). All these variables were assessed pre‐ and post‐ both the control and mentally fatiguing task. A condition × time interaction was found for perceived mental fatigue, the Stroop performance and PVT reaction time (p < 0.001) and for padel‐specific accuracy on all strokes (p < 0.001). The perceived level of mental fatigue increased, while PVT reaction time and Stroop performance (i.e., amount of words) were impaired in time only in the mental fatigue condition. The accuracy of all padel strokes was significantly impaired from pre to post only in the mental fatigue condition (p < 0.050). In conclusion, mental fatigue impairs padel‐specific accuracy in young elite male padel players. Consequently, we recommend coaches to consider the level of mental fatigue during padel trainings and competitions. Highlights: The result of the present study shows that mental fatigue induced by a 30‐min incongruent Stroop task, impaired the accuracy and the speed of different padel‐specific strokes in youth‐elite male players.The presence of mental fatigue during official padel competitions has been previously confirmed. Then, it might of course impact the outcome of the match, as the number of forced and unforced errors or the speed of the shots are important indicators of padel‐specific performance.This information highlights the need for coaches and staff to consider the amount of mental fatigue generated during padel trainings and matches. Coaches are able to modulate the level of mental fatigue of the trainings. [ABSTRACT FROM AUTHOR]

Athletes often undertake intensified training loads prior to competition with the goal of functionally overreaching for temporary performance enhancement; however, little is known about the impact of this on cognitive function. The aim of this study was to investigate the effect of intensified training induced fatigue on cognitive function, psychological state and performance in trained cyclists. Twenty-three trained male cyclists were randomly assigned to an intensified training group or a control group for two-weeks, followed by a two-week taper period. At baseline, one-week, two-weeks and post-taper, participants undertook a series of cognitive, performance, mood and recovery-stress assessments. The training intervention significantly increased training volume, load and strain by 108%, 116% and 151% respectively. Peak and mean power output on a maximal test and time trial significantly decreased by 4.8% and 9.4% following the two-week training intervention compared to baseline, in addition to a 169% change in total mood disturbance and significant disruption to recovery-stress balance. No change in any cognitive measure was observed across the study period. Following a two-week taper, performance, mood and well-being measures returned to baseline. Two weeks of intensified training resulted in overreaching as identified by performance and psychological measures. Cognitive function was not sensitive to intensified training promoting caution with its use as a measure for the early identification of overreaching. Highlights Two-weeks of intensified training significantly increased training volume, load and strain eliciting a state of overreaching in trained male cyclists. Intensified training caused deteriorations in physical performance but did not influence cognitive measures. Mood and recovery-stress balance were negatively affected by intensified training but recovered back to baseline following a two-week taper at a reduced training volume. A two-week taper period following two-weeks of intensified training did not result in improved physiological measures, physical performance parameters or mood above initial baseline values highlighting the need for careful consideration over the purpose, desired outcomes and necessity of intensified training on an individualised basis. [ABSTRACT FROM AUTHOR]

Reducing injuries to youth players is of primary importance to academies, as injuries can result in a significant loss in both training and match time, as well as, negatively affecting player development. In total, 76 talented young football players were analysed over two full competitive seasons. The injury incidence and burden for all non-contact and overuse injuries were recorded. Exposure was calculated as the total number of competitive matches hours played. Somatic maturation was estimated by expressing the current height of each player as a percentage of their predicted adult height [Roche, A. F., Tyleshevski, F., & Rogers, E. (1983). Non-invasive measurements of physical maturity in children. Research Quarterly for Exercise and Sport, 54(4), 364–371.]. The period of circa-peak height velocity (PHV) (24.5 injuries per 1000 h) was associated with a significantly higher injury incidence rate and burden compared to pre-PHV (11.5 injuries per 1000 h; RR:2.15, 95%CI:1.37–3.38, P <.001). No significant differences in injury risk between maturity timing groups were observed. The interaction effect between maturity status and maturity timing confirmed there is a risk period circa-PHV, but this was not dependent on maturity timing. The main practical application of this study is that football academies should regularly assess the maturity status of young footballers to identify those players with increased susceptibility to injury. Moreover, academies should individualise training and injury prevention strategies based on maturation. [ABSTRACT FROM AUTHOR]

The impact of extensive loads on the cartilage of the proximal interphalangeal- (PIP) and distal interphalangeal (DIP) joints of the fingers in elite sport climbers are relatively unknown. The purpose of this study was to investigate the changes in the cartilage of the PIP and DIP joints as well as the existence of osteophytes, in fingers of elite sport climbers with a minimum of 15 years of climbing history. Thirty-one elite male sport climbers and 20 male non-climbers volunteered for the current cross-sectional observation. By means of ultrasonography, the thickness of cartilage of the PIP and DIP joints in a sagittal and frontal plane of the digits II to V of both hands, as well as the existence of osteophytes on the dorsal aspect of the phalanges were assessed. The main results were: (1) cartilage thickness revealed to be significantly greater in climbers than non-climbers,; (2) larger cartilage thickness differences were found at the DIP joints; (3) while climbers showed a substantial occurrence of osteophytes with highest relative frequencies at Dig III, in the group of non-climbers no osteophytes were observed; (4) small to moderate correlations were found between the cartilage and osteophyte thickness of climbers at the PIP and DIP joints and Dig III. In conclusion, an accumulation of repetitive climbing-related stress to the fingers of elite sport climbers over the career may induce degenerative changes at the PIP and DIP joints. [ABSTRACT FROM AUTHOR]

This study aimed to examine internal loads in male adolescent Gaelic footballers and their association with musculoskeletal injury. Written training diaries were completed by 97 male adolescent Gaelic footballers weekly and injuries, defined as any injury sustained during training or competition causing restricted performance or time lost from play, were assessed by a Certified Athletic Therapist. Daily load was determined for each player (session rating of perceived exertion by session duration) and summed to give weekly load. Univariate and multiple logistic regressions were conducted to determine the association with injury. Twenty-two injuries were recorded with match injuries significantly more common than training injuries. Periodic variations in weekly load and injuries were evident throughout the season. Univariate analysis identified weekly load (OR = 2.75; 95%CI = 1.00–7.59), monotony (OR = 4.17; 95%CI = 1.48–11.72) and absolute change in load (OR = 3.27; 95%CI = 1.15–9.32) greater than the team average were significant injury risk factors. Multiple logistic regression with 2-weekly and 3-weekly cumulative loads, absolute change, monotony, strain, ACWR and age as independent variables identified internal load measures (monotony, strain and absolute change) were associated with injury with high specificity (96.0%) but low sensitivity (25.0%). The findings highlight the need to monitor team and individual loads to avoid sudden week-to-week changes or excessive weekly loads. Open communication between players, parents, coaches and sports medicine clinicians enables effective load monitoring that can reduce injury risk and may subsequently minimise dropout, improve team success and overall sport enjoyment and promote life-long sports participation. [ABSTRACT FROM AUTHOR]

We developed the Fatigue and Fitness Test for Teams (FFITT) to address the challenges of monitoring players in a team simultaneously. The test, which takes 8 min for the entire team, incorporates subjective measures of well-being (RTT-Q), and objective measures of the autonomic system (HRR60s) and neuromuscular function (SLJ). The aim of this study was to present the rationale for the FFITT as a novel athlete monitoring protocol and to measure the reliability of each component of the test. The internal consistency of the RTT-Q questions ranged from α = 0.69–0.92. All questions had an α > 0.83, with one exception of question 'Rate the well-being/stress your school/university/work is causing you to feel' which had an α = 0.69. The reliability of the HRR60s and SLJ was high (R = 0.92, and 0.91 respectively). The absolute typical error of measurement (TEM) of the SLJ was 8 cm and HRR60s was 3 beats. When expressed relatively the CVTEM of HRR60s was 8.4% and SLJ was 3.0%. Based on the TEM the HRR60s and SLJ could detect medium and large changes in fatigue and fitness. In absolute terms this equates to more than 5 bpm (HRR60s) and more than 13 cm (SLJ). The FFITT has the potential to satisfy both scientific principles and the coach's demands of a practical monitoring protocol for frequent use in a team. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate whether the change in (sub)maximal heart rate after intensified training is associated with the change in performance. Thirty subjects were recruited who performed cardiopulmonary exercise tests to exhaustion 2 weeks before (pre), 1 week after (post) and 5 weeks after (follow-up) an 8-day non-competitive amateur cycling event (TFL). The exercise volume during the TFL was 7.7 fold the volume during the preparation period. Heart rate and cardiopulmonary parameters were obtained at standardised absolute submaximal workloads (low, medium and high intensity) and at peak level each test. Subjects were classified as functionally overreached (FOR) or acute fatigued (AF) based on the change in performance. No differences between FOR and AF were observed for heart rate (P =.51). On total group level (AF + FOR), post-TFL heart rate decreased significantly at low (−4.4 beats·min−1, 95% CI [−8.7, −0.1]) and medium (−5.5 beats·min−1 [−8.5, −2.4]), but not at high intensity. Peak heart rate decreased −3.4 beats·min−1 [−6.1, −0.7]. O2pulse was on average 0.49 ml O2·beat−1 [0.09, 0.89] higher at all intensities after intensified training. No changes in ⩒O2 (P =.44) or the ventilatory threshold (P =.21) were observed. Pearson's correlation coefficients revealed negative associations between heart rate and O2pulse at low (r = −.56, P <.01) and medium intensity (r = −.54, P <.01), but not with ⩒O2 or any other submaximal parameter. (Sub)maximal heart rate decreased after the TFL. However, this decrease is unrelated to the change in performance. Therefore, heart rate seems inadequate to prescribe and monitor intensified training. [ABSTRACT FROM AUTHOR]

Physiological or performance tests are routinely utilised to assess athletes’ recovery. At present, the ideal tool to assess recovery remains unknown. Therefore, the aim of this systematic review was to examine the change in creatine kinase (CK) and neuromuscular function as measured via a countermovement jump (CMJ) following a match in the contact codes of football. A comprehensive search of databases was undertaken with RevMan (V 5.3) used for statistical analysis. Our results demonstrated that CK pre- versus post-match (standardised mean difference (SMD) = 0.90, 95% CI = 0.50 to 1.31, p < .0001), CK pre- versus 24 h post-match (SMD = 1.50, 95% CI = 1.12 to 1.88, p < .00001), and CK pre- versus 48 h post-match all increased significantly (SMD = 0.90, 95% CI = 0.50 to 1.31, p < .0001), while CMJ peak power (PP) pre- versus post-match (SMD = −0.59, 95% CI = −1.12 to −0.06, p = .03), and pre- versus 24 h post-match (SMD = −0.80, 95% CI = −1.31 to −0.28, p = .002) decreased significantly. There was a significant relationship between the change in CK and the change in CMJ PP from immediately pre to immediately post (r = −0.924, p = .025), and between CMJ immediately following a match and 24 h CK change (r = −0.983, p = .017). In conclusion, CK levels increase and performance in the CMJ decreases following a match of a contact code of football. The identification of this relationship may allow coaching staff to implement a standalone measure of recovery. [ABSTRACT FROM AUTHOR]

The use of heart rate variability (HRV) to inform daily training prescription is becoming common in endurance sport. Few studies, however, have investigated the use of pre-training HRV to predict decreased performance or altered exercising autonomic response, typical of functional overreaching (FOR). Further, a new cardiac vagal tone (ProCVT) technology purports to eliminate some of the noise associated with daily HRV, and therefore may be better at predicting same-day performance. The purpose of this investigation was to examine if changes to resting HRV and ProCVT were associated with alterations in performance, maximal heart rate (HRmax), or heart rate recovery (HRrec) in FOR athletes. Twenty-eight recreational cyclists and triathletes were assigned to experimental/control conditions and underwent: 1 week of reduced training, 3 weeks of overload (OL) or regular training (CON), and 1 week of recovery. Testing occurred following the reduced training week (T1), post-3 weeks of training (T2), and following the recovery week (T3). Measures of resting HRV/ProCVT were collected each testing session, followed by maximal incremental exercise tests with HRrec taken 60 s post-exercise. Performance decreased from T1 to T2 in the OL group vs. CON (Δ−9 ± 12 vs. Δ9 ± 11 W, P < .001), as did HRmax (Δ−8 ± 4 vs. Δ−2 ± 4 bpm, P < .001). HRrec increased from T1 to T2 in the OL group vs. CON (Δ10 ± 9 vs. Δ2 ± 5 beats/min, P < .01). HRV and ProCVT did not change in either group. Same-day resting autonomic measures are insufficient in predicting alterations to performance or exercising HR measures following overload training.  [ABSTRACT FROM AUTHOR]

Training distress occurs when athletes fail to cope with physiological and psychological stress and can be an early sign of overtraining syndrome. Recent research has found that perfectionism predicts increases in training distress in junior athletes over time. The current study provides the first empirical test of the possibility that coping tendencies mediate the perfectionism-training distress relationship. Adopting a cross-sectional design, 171 junior athletes (mean age = 18.1 years) completed self-report measures of perfectionistic strivings, perfectionistic concerns, problem-focused coping, avoidant coping, and training distress. Structural equation modelling revealed that avoidant coping mediated the positive relationship between perfectionistic concerns and training distress, and mediated the negative relationship between perfectionistic strivings and training distress. Problem-focused coping did not mediate any relationships between dimensions of perfectionism and training distress. The findings suggest that the tendency to use coping strategies aimed at avoiding stress may partly explain the relationship between perfectionism and training distress but the tendency to use, or not use, problem-focussed coping does not. [ABSTRACT FROM AUTHOR]

This study investigated the effect of increased high-intensity interval training (HIT) at the expense of total training volume on the stress and recovery levels of elite swimmers. Forty-one elite swimmers participated in the study and were randomly assigned to either a HIT or a control group (CON). Eleven swimmers did not complete the questionnaires. For 12 weeks both groups trained ~12 h per week. The amount of HIT was ~5 h vs. 1 h, and total distance was ~17 km vs. ~35 km per week for HIT and CON, respectively. HIT was performed as 6–10 × 10–30 s maximal effort interspersed by 2–4 min of rest. The Recovery Stress Questionnaire – Sport was used to measure the swimmers’ stress and recovery levels. After the 12 week intervention, the general stress level was 16.6% (2.6–30.7%; mean and 95% CI) lower and the general recovery level was 6.5% (0.7–12.4%) higher in HIT compared to the CON, after adjusting for baseline values. No significant effects could be observed in sports-specific stress or sports-specific recovery. The results indicate that increasing training intensity and reducing training volume for 12 weeks can reduce general stress and increase general recovery levels in competitive swimmers. [ABSTRACT FROM AUTHOR]

The aim of the present study was to find early markers for overreaching that are applicable in sport practice. In a group of elite soccer players aged 15–18, the stress–recovery balance and reaction times before and after exercise were assessed. Overreaching was indicated by an elevated submaximal heart rate during a sport-specific field test. Submaximal changes in heart rate were prospectively monitored by means of monthly Interval Shuttle Run Tests during two competitive seasons. Out of 94 players, seven players with an elevated heart rate of at least one month could be included in the study, together with seven controls, matched for age, body composition, training and performance level. The stress–recovery balance was assessed with the Dutch version of the Recovery Stress Questionnaire (RESTQ-Sport). The soccer players with an elevated heart rate reported a disturbed stress–recovery balance (Mann–Whitney test,P<0.05). An ANOVA for repeated measures of reaction times revealed a significant main effect of time (F1,12=13.87,P<0.01) indicating an improvement of psychomotor speed. No differences between groups were found. We conclude that soccer players with an elevated submaximal heart rate of at least one month share a disturbed stress–recovery balance, but they could not be distinguished from controls based on reaction time after strenuous exercise. [ABSTRACT FROM PUBLISHER]

Successful training must involve overload, but also must avoid the combination of excessive overload plus inadequate recovery. Athletes can experience short-term performance decrement, without severe psychological, or lasting other negative symptoms. This Functional Overreaching (FOR) will eventually lead to an improvement in performance after recovery. When athletes do not sufficiently respect the balance between training and recovery, Non-Functional Overreaching (NFOR) can occur. The distinction between NFOR and the Overtraining Syndrome (OTS) is very difficult and will depend on the clinical outcome and exclusion diagnosis. The athlete will often show the same clinical, hormonal and other signs and symptoms. A keyword in the recognition of OTS might be ‘prolonged maladaptation’ not only of the athlete, but also of several biological, neurochemical, and hormonal regulation mechanisms. It is generally thought that symptoms of OTS, such as fatigue, performance decline and mood disturbances, are more severe than those of NFOR. However, there is no scientific evidence to either confirmor refute this suggestion. One approach to understanding the aetiology of OTS involves the exclusion of organic diseases or infections and factors such as dietary caloric restriction (negative energy balance) and insufficient carbohydrate and/or protein intake, iron deficiency, magnesium deficiency, allergies, etc., together with identification of initiating events or triggers. In this paper, we provide the recent status of possible markers for the detection of OTS. Currently several markers (hormones, performance tests, psychological tests, biochemical and immune markers) are used, but none of them meets all criteria to make its use generally accepted. [ABSTRACT FROM PUBLISHER]

Passion is a strong motivational force towards an activity considered very important, possibly to the extent that the activity forms a part of an individual's identity. Two forms of passion, harmonious and obsessive, are thought to lead to different cognitive and affective responses. Although being passionate about sport appears to be important from a motivational perspective, it possibly also increases the risk for burnout, which is a negative consequence blamed partly on too much training and inadequate recovery. The question voiced in this study is whether harmonious passion and obsessive passion pose equal risks for burnout. Participants were 94 female and 164 male competitive athletes from 21 sports. The results, analysed using partial correlation and multivariate analyses of variance, showed that athletes with an obsessive passion scored higher on a burnout inventory than did harmoniously passionate athletes. Obsessively passionate athletes also scored higher on perceived stress and negative affect, and lower on positive affect. These findings support the assumption that even though the two forms of passion may be an integral part of elite sports, athletes scoring high on obsessive passion may be at greater risk of developing burnout than more harmoniously passionate athletes. Burning bright and burning out can thus be seen as two potential consequences for athletes driven by passion. Athletes and coaches who are aware of this may be better equipped to avoid the potential negative consequences associated with too much stress and too little recovery. [ABSTRACT FROM AUTHOR]

The goal of the present study was to determine if psychomotor speed is related to perceived performance. It was hypothesized that lower perceived performance was related to longer reaction times. A total of 85 measurements were taken in 26 varsity rowers (mean age 21.3 years, s=1.6) on five occasions over the course of the season. Perceived performance was measured with the “Reduced Sense of Accomplishment” scale of the Athlete Burnout Questionnaire. Reaction times were measured with the finger pre-cueing task and with the action and reaction modes of the determination test. The complex structured data were analysed with multi-level modelling. Random intercept linear models showed that perceived performance was not related to reaction times on the finger pre-cueing task. Perceived performance significantly predicted reaction times on the action and reaction modes of the determination test. In rowers who were not selected for the team after completing two measurement sessions, this relationship did not exist in the action mode; deselection was a moderator. Thus, a significant relationship between reaction times on the determination test and perceived performance was observed. It was concluded that the determination test could be a useful tool to monitor rowers' responses to training, although several issues should be resolved before it can be used in practice. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine whether quality of self-determined motivation at the start of the competitive season in elite athletes and symptoms of overtraining can predict athlete burnout propensity at the end of the season. The participants were 141 elite winter sport athletes. In September, at the beginning of the season, the athletes responded to a self-determined motivation questionnaire, while they answered questions assessing overtraining symptoms and burnout in March, at the end of the season. Findings indicated that self-determined motivation and symptoms of overtraining were negatively and positively linked respectively to dimensions of athlete burnout. The results suggest that self-determined motivation and symptoms of overtraining are both independently linked to signs of burnout in elite athletes and that although no moderating effect was found, pairing self-determined motivation with symptoms of overtraining increased the prediction of burnout in athletes at the end of the season. Our findings are in line with those of recent research (Cresswell & Eklund, 2005; Lemyre, Treasure, & Roberts, 2006) and support a motivational approach to study burnout in elite athletes. [ABSTRACT FROM AUTHOR]

Successful training must involve overload but also must avoid the combination of excessive overload plus inadequate recovery. Athletes can experience short term performance decrement, without severe psychological, or lasting other negative symptoms. This Functional Overreaching (FOR) will eventually lead to an improvement in performance after recovery. When athletes do not sufficiently respect the balance between training and recovery, Non-Functional Overreaching (NFOR) can occur. The distinction between NFOR and the Overtraining Syndrome (OTS) is very difficult and will depend on the clinical outcome and exclusion diagnosis. The athlete will often show the same clinical, hormonal and other signs and symptoms. A keyword in the recognition of OTS might be ‘prolonged maladaptation’ not only of the athlete, but also of several biological, neurochemical, and hormonal regulation mechanisms. It is generally thought that symptoms of OTS, such as fatigue, performance decline, and mood disturbances, are more severe than those of NFOR. However, there is no scientific evidence to either confirm or refute this suggestion. One approach to understanding the aetiology of OTS involves the exclusion of organic diseases or infections and factors such as dietary caloric restriction (negative energy balance) and insufficient carbohydrate and/or protein intake, iron deficiency, magnesium deficiency, allergies, etc. together with identification of initiating events or triggers. In this paper we provide the recent status of possible markers for the detection of OTS. Currently several markers (hormones, performance tests, psychological tests, biochemical and immune markers) are used, but none of them meets all criteria to make its use generally accepted. We propose a “check list” that might help the physicians and sport scientists to decide on the diagnosis of OTS and to exclude other possible causes of underperformance. [ABSTRACT FROM AUTHOR]

Serotonin (5-HT) regulates the most extensive modulatory behavioral system in the brain of vertebrates. 5-HT projections are influenced by extrinsic and intrinsic impulses from different cortical brain areas, which reach Raphe nuclei over feedback loops, containing external and internal body information about planning, evaluation, motivation, or excitation. Serotonergic neurotransmission adjusts neuromodulation with consecutive adequate stimulation of the neuronal network. This depends on appropriate equilibration of presynaptic 5-HT storage and release but also on 5-HT reuptake from synaptic cleft by 5-HT transporters. The associated pre- and postsynaptic 5-HT receptor cooperation, postsynaptic second messenger response, and phosphoinositide signaling mediated by postsynaptic 5-HT[sub2] receptor subpopulation alter signal transduction in which myristolated alanine rich C kinase substrate is prominently involved in regulation of further central 5-HT areas in the brain and corresponding functional neuronal changes. Even though the central function of 5-HT neurotransmission is dominating in multifold behavioral regulation, peripheral concentration of tryptophan (TRP) and TRP passage across the blood-brain barrier and TRP hydroxylase activity are also important for appropriate 5-HT neurotransmission, as they affect central 5-HT synthesis. The high adaptability of 5-HT neurotransmission is able to compensate neuromodular dysfunctions in the brain by mechanisms that mediate 5-HT biosynthesis, release, reuptake, pre-and postsynaptic receptor stimulation with the respective second messenger response, and signal transduction to various areas of the brain that are involved in regulation of behavior, mood, memory, learning, and attenuation of obsession. Adequate 5-HT system function supports regulation of intercommunicative neuronal transmission in the brain, which optimizes behavioral neuromodulation during and after transient disturbances of neuromodular behavior caused... [ABSTRACT FROM AUTHOR]

The author reflects on the prevention, diagnosis and treatment of the overtraining syndrome. He emphasizes difficulty concerning the definitions of overtraining terminologies since he believes it is part of the research projects in overtraining and in the diagnosis of a patient. He further suggests that overtraining research should specify substantial indications using tools that would interpret the state of overtrained athletes.

The purpose of this study was to measure the influence of breathing frequency (BF) on heart rate variability (HRV) and specifically on the Low Frequency/High Frequency (LF/HF) ratio in athletes. Fifteen male athletes were subjected to HRV measurements under six randomised breathing conditions: spontaneous breathing frequency (SBF) and five others at controlled breathing frequencies (CBF) (0.20; 0.175; 0.15; 0.125 and 0.10 Hz). The subjects were divided in two groups: the first group included athletes with SBF <0.15 Hz (infSBF) and the second athletes with SBF higher than 0.15 Hz (supSBF). Fatigue and training load were evaluated using a validated questionnaire. There was no difference between the two groups for the fatigue questionnaire and training load. However, the LF/HF ratio during SBF was higher ininfSBFthan insupSBF(6.82±4.55 vs. 0.72±0.52; p<0.001). The SBF and LF/HF ratio were significantly correlated (R=−0.69;p=0.004). For the five CBF, no differences were found between groups; however, LF/HF ratios were very significantly different between sessions at 0.20; 0.175; 0.15 Hz and 0.125; 0.10 Hz. In this study, BF was the main modulator of the LF/HF ratio in both controlled breathing and spontaneous breathing. Although, none of the subjects of theinfSBFgroup were overtrained, during SBF they all presented LF/HF ratios higher than four commonly interpreted as an overtraining syndrome. During each CBF, all athletes presented spectral energy mainly concentrated around their BF. Consequently, spectral energy was located either in LF or in HF band. These results demonstrate that the LF/HF ratio is unreliable for studying athletes presenting SBF close to 0.15 Hz leading to misclassification in fatigue. [ABSTRACT FROM AUTHOR]

The author reflects on the reviewed possible signs and symptoms of the Overtraining Syndrome and the arrangement on the outcome of overload training. He stresses that the decrease in performance on overload training was due to the Functional Overreaching episode. He also believes that symptoms and several signs for Overtraining Syndrome needs to be examined to better identify its precise diagnosis.