Redefining the overtraining syndrome as the unexplained underperformance syndrome

The Potential Role of Nutrition in Overtraining Syndrome: A Narrative Review

Competition between athletes and an increase in sporting knowledge have greatly influenced training methods while increasing the number of them more and more. As a result, the number of athletes who have increased the number and intensity of their workouts while decreasing recovery times is rising. Positive overtraining could be considered a natural and fundamental process when the result is adaptation and improved performance; however, in the absence of adequate recovery, negative overtraining could occur, causing fatigue, maladaptation, and inertia. One of the earliest forms of fatigue is overreaching. It is considered to be an accumulation of training that leads to reduced sports performance, requiring days or weeks to recover. Overreaching, if followed by adequate recovery, can lead to an increase in athletic performance. Nonetheless, if overreaching becomes extreme, combined with additional stressors, it could lead to overtraining syndrome (OTS). OTS, caused by systemic inflammation, leads to central nervous system (CNS) effects, including depressed mood, further inflammation, central fatigue, and ultimately neurohormonal changes. There are therefore not only physiological, biochemical, and immunological but also psychological symptoms or markers that must be considered, independently or together, being intrinsically linked with overtraining, to fully understand OTS. However, to date, there are very few published studies that have analyzed how nutrition in its specific food aspects, if compromised during OTS, can be both etiology and consequence of the syndrome. To date, OTS has not yet been fully studied, and the topic needs further research. The purpose of this narrative review is therefore to study how a correct diet and nutrition can influence OTS in all its aspects, from prevention to treatment.

Association between Self-reported Overtraining Syndrome and Symptoms in High School Track and Field Athletes

Diagnosing overtraining syndrome is challenging and it is often correlated with other diseases, especially those related to low energy availability. Therefore, we investigated the prevalence of overtraining syndrome-like symptoms and correlative factors in 389 female and 572 male national-level high school track and field athletes. They were asked to complete a survey regarding their history of overtraining syndrome-like symptoms, injuries, and diseases. The survey results revealed that 13.4% (52/389) of female and 13.3% (76/572) of male athletes had a history of overtraining syndrome-like symptoms. Logistic regression analysis showed that training hours per day (odds ratio, 1.74; 95% confidence interval, 1.12-2.71) was an associated factor in female athletes, while rest days per week (odds ratio, 0.61; 95% confidence interval, 0.37-1.00), skipping meals (odds ratio, 3.73; 95% confidence interval, 1.50-9.29), and having snacks/light meals on a regular basis (odds ratio, 0.46; 95% confidence interval, 0.26-0.83) were the associated factors in male athletes. In conclusion, athletes with overtraining syndrome-like symptoms may be prone to injuries and diseases. Hence, although overtraining syndrome is difficult to diagnose, further attention should be paid to minimize overtraining syndrome-related risks.

Potential Long-Term Health Problems Associated with Ultra-Endurance Running: A Narrative Review

It is well established that physical activity reduces all-cause mortality and can prolong life. Ultra-endurance running (UER) is an extreme sport that is becoming increasingly popular, and comprises running races above marathon distance, exceeding 6 h, and/or running fixed distances on multiple days. Serious acute adverse events are rare, but there is mounting evidence that UER may lead to long-term health problems. The purpose of this review is to present the current state of knowledge regarding the potential long-term health problems derived from UER, specifically potential maladaptation in key organ systems, including cardiovascular, respiratory, musculoskeletal, renal, immunological, gastrointestinal, neurological, and integumentary systems. Special consideration is given to youth, masters, and female athletes, all of whom may be more susceptible to certain long-term health issues. We present directions for future research into the pathophysiological mechanisms that underpin athlete susceptibility to long-term issues. Although all body systems can be affected by UER, one of the clearest effects of endurance exercise is on the cardiovascular system, including right ventricular dysfunction and potential increased risk of arrhythmias and hypertension. There is also evidence that rare cases of acute renal injury in UER could lead to progressive renal scarring and chronic kidney disease. There are limited data specific to female athletes, who may be at greater risk of certain UER-related health issues due to interactions between energy availability and sex-hormone concentrations. Indeed, failure to consider sex differences in the design of female-specific UER training programs may have a negative impact on athlete longevity. It is hoped that this review will inform risk stratification and stimulate further research about UER and the implications for long-term health.

"Is It Overtraining or Just Work Ethic?": Coaches' Perceptions of Overtraining in High-Performance Strength Sports

Optimal physical performance is achieved through the careful manipulation of training and recovery. Short-term increases in training demand can induce functional overreaching (FOR) that can lead to improved physical capabilities, whereas nonfunctional overreaching (NFOR) or the overtraining syndrome (OTS) occur when high training-demand is applied for extensive periods with limited recovery. To date, little is known about the OTS in strength sports, particularly from the perspective of the strength sport coach. Fourteen high-performance strength sport coaches from a range of strength sports (weightlifting; n = 5, powerlifting; n = 4, sprinting; n = 2, throws; n = 2, jumps; n = 1) participated in semistructured interviews (mean duration 57; SD = 10 min) to discuss their experiences of the OTS. Reflexive thematic analysis resulted in the identification of four higher order themes: definitions, symptoms, recovery and experiences and observations. Additional subthemes were created to facilitate organisation and presentation of data, and to aid both cohesiveness of reporting and publicising of results. Participants provided varied and sometimes dichotomous perceptions of the OTS and proposed a multifactorial profile of diagnostic symptoms. Prevalence of OTS within strength sports was considered low, with the majority of participants not observing or experiencing long-term reductions in performance with their athletes.

Mood Profiling for Sustainable Mental Health among Athletes

Mood responses are a well-established mental health indicator. Gauging mental health status over time often involves periodic mood assessment using a standardized measure, a process referred to as mood profiling. Comparison of observed mood scores against relevant normative data is central to effective mood profiling. The primary purpose of our study was to improve existing norms for the Brunel Mood Scale (BRUMS) using a large internet sample. The secondary purpose was to discuss how mood profiling can be used to promote sustainable mental health primarily among athletes but also with relevance to non-athletes. The BRUMS was completed via the In The Mood website by 15,692 participants. Significant differences between observed mean scores and existing normative data were evident for all six mood dimensions, prompting norm refinement. Specific group norms were generated to address sex differences in mood responses and differences by athlete/nonathlete status. The revised tables of normative data for the BRUMS should be used by researchers in future investigations of mood responses and by applied practitioners seeking to monitor mood responses as an indicator of mental health status. Applications of mood profiling with elite athletes are exemplified, along with recommendations for using mood profiling in the pursuit of sustainable mental health.

Novel Markers of Recovery From Overtraining Syndrome: The EROS-LONGITUDINAL Study

PURPOSES

Overtraining syndrome (OTS) is an unexplained underperformance syndrome triggered by excessive training, insufficient caloric intake, inadequate sleep, and excessive cognitive and social demands. Investigation of the recovery process from OTS has not been reported to date. The objective was to unveil novel markers and biochemical and clinical behaviors during the restoration process of OTS.

METHODS

This was a 12-week interventional protocol in 12 athletes affected by OTS, including increase of caloric intake, transitory interruption of training, improvement of sleep quality, and management of stress, followed by the assessment of 50 parameters including basal and hormonal responses to an insulin tolerance test and nonhormonal biochemical markers, and body metabolism and composition.

RESULTS

Early cortisol (P = .023), late ACTH (adrenocorticotrophic hormone) (P = .024), and early and late growth hormone (P = .005 and P = .038, respectively) responses, basal testosterone (P = .038), testosterone:estradiol ratio (P = .0005), insulinlike growth factor 1 (P = .004), cortisol awakening response (P = .001), and free thyronine (P = .069) increased, while basal estradiol (P = .033), nocturnal urinary catecholamines (P = .038), and creatine kinase (P = .071) reduced. Conversely, markers of body metabolism and composition had slight nonsignificant improvements.

CONCLUSION

After a 12-week intervention, athletes affected by actual OTS disclosed a mix of non-, partial, and full recovery processes, demonstrating that remission of OTS is as complex as its occurrence.

Exercise Time and Intensity: How Much Is Too Much?

The growing prevalence and popularity of interval training necessitate additional guidelines in regard to maximal levels of time and intensity.

PURPOSE

To correlate salivary hormones and time in varying heart-rate (HR) zones. The hypothesis was that chronic exercise durations >9% of total exercise time in the >90% maximum HR zone would lead to decreased variation in salivary cortisol concentration after exercise in a 2-bout high-intensity protocol compared with less or more time in this zone.

METHODS

A total of 35 healthy adults who regularly exercised for an average of 8 hours per week recorded their HR during every training session for 3 weeks. Later, they completed an experimental day composed of two 30-minute high-intensity interval sessions separated by 4 hours of nonactive recovery. The authors collected saliva samples before, immediately following, and 30 minutes after each exercise session to assess changes in cortisol concentrations.

RESULTS

There was a correlation between weekly time training at an intensity >90% maximum HR and the variables associated with overtraining. Salivary cortisol concentration fluctuated less in the participants who exercised in this extreme zone for >40 minutes per week (P < .001).

CONCLUSION

Based on the current study data, for individuals who regularly exercise, 4% to 9% total training time above 90% maximum HR is the ideal duration to maximize fitness and minimize symptoms related to overreaching.

Hypogonadism in Exercising Males: Dysfunction or Adaptive-Regulatory Adjustment?

For decades researchers have reported men who engaged in intensive exercise training can develop low resting testosterone levels, alterations in their hypothalamic-pituitary-gonadal (HPG) axis, and display hypogonadism. Recently there is renewed interest in this topic since the International Olympic Committee (IOC) Medical Commission coined the term "Relative Energy Deficiency in Sports" (RED-S) as clinical terminology to address both the female-male occurrences of reproductive system health disruptions associated with exercise. This IOC Commission action attempted to move beyond the sex-specific terminology of the "Female Athlete Triad" (Triad) and heighten awareness/realization that some athletic men do have reproductive related physiologic disturbances such as lowered sex hormone levels, HPG regulatory axis alterations, and low bone mineral density similar to Triad women. There are elements in the development and symptomology of exercise-related male hypogonadism that mirror closely that of women experiencing the Triad/RED-S, but evidence also exists that dissimilarities exist between the sexes on this issue. Our research group postulates that the inconsistency and differences in the male findings in relation to women with Triad/RED-S are not just due to sex dimorphism, but that there are varying forms of exercise-related reproductive disruptions existing in athletic men resulting in them displaying a relative hypogonadism condition. Specifically, such conditions in men may derive acutely and be associated with low energy availability (Triad/RED-S) or excessive training load (overtraining) and appear transient in nature, and resolve with appropriate clinical interventions. However, manifestations of a more chronic based hypogonadism that persists on a more permanent basis (years) exist and is termed the "Exercise Hypogonadal Male Condition." This article presents an up-to-date overview of the various types of acute and chronic relative hypogonadism found in athletic, exercising men and proposes mechanistic models of how these various forms of exercise relative hypogonadism develop.

Sports psychiatry: mental health and mental disorders in athletes and exercise treatment of mental disorders

Sports psychiatry has developed for the past 3 decades as an emerging field within psychiatry and sports medicine. An International society has been established in 1994 and also national interest groups were implemented, mostly within the national organizations for psychiatry, some also containing the topic of exercise treatment of mental disorders. Where are we now 30 years later? We systematically but also selectively review the medical literature on exercise, sport, psychiatry, mental health and mental disorders and related topics. The number of publications in the field has increased exponentially. Most topics keep remaining on the agenda, e.g., head trauma and concussion, drug abuse and doping, performance enhancement, overtraining, ADHD or eating disorders. Supported by the growing literature, evidence-based recommendations have become available now in many clinical areas. A relatively new phenomenon is muscle dysmorphia, observed in weightlifters, bodybuilders but also in college students and gym users. Further, sports therapy of mental disorders has been studied by more and more high-quality randomized controlled clinical trials. Mostly as a complementary treatment, however, for some disorders already with a 1a evidence level, e.g., depression, dementia or MCI but also post-traumatic stress disorder. Being grown up and accepted nowadays, sports psychiatry still represents a fast-developing field. The reverse side of the coin, sport therapy of mental disorders has received a scientific basis now. Who else than sports psychiatry could advance sport therapy of mental disorders? We need this enthusiasm for sports and psychiatry for our patients with mental disorders and it is time now for a broadening of the scope. Optimized psychiatric prevention and treatment of athletes and ideal sport-related support for individuals with mental disorders should be our main purpose and goal.

DIAGNOSIS OF OVERTRAINING SYNDROME

ABSTRACT Overtraining syndrome (OTS) is a condition associated with diminished sports performance due to an increase in the volume and/or intensity of physical activity without adequate rest, and/or due to an inadequate diet. The condition often involves hormonal, nutritional, emotional, muscle, immune and neurological imbalances. Epidemiology varies considerably, affecting both sexes in different age groups. Diagnosis is still a challenge, as the syndrome resembles different diseases. The lack of specific symptoms requires a meticulous investigation in all athletes, which is often multidisciplinary. OTS can have an important repercussion on sports performance and on the quality of life of athletes. Methods: This is a mapping of scientific literature along the lines of the Systemic Review. The databases investigated were: MEDLINE and Latin American and Caribbean Health Sciences Literature – LILACS and EMBASE, in addition to printed documents. Studies describing OTS were included, prioritizing articles that report the efficacy of the different diagnostic methods, be they clinical, laboratory, or imaging. Results: We found 83 articles, of which 30 were selected. Conclusion: The only symptom present in all the different forms of manifestation of OTS is loss of performance. However, some tests assessing oxidative stress levels seem promising, even though they are not specific. Revision article.

Body composition, metabolism, sleep, psychological and eating patterns of overtraining syndrome: Results of the EROS study (EROS-PROFILE)

Overtraining syndrome (OTS) is caused by an imbalance between training, nutrition and resting, and leads to decreased performance and fatigue; however, the precise underlying triggers of OTS remain unclear. This study investigated the body composition, metabolism, eating, sleeping patterns and mood states among participants with OTS. Selected participants were divided into OTS-affected athletes (OTS, n = 14), healthy athletes (ATL, n = 25), and healthy non-physically active controls (NCS, n = 12). Compared to ATL, OTS showed decreased sleep quality (p = 0.004); increased duration of work or study (p < 0.001); decreased libido (p = 0.024); decreased calorie (p < 0.001), carbohydrate (p < 0.001) and protein (p < 0.001) intakes; decreased mood states (p < 0.001); decreased basal metabolic rate (p = 0.013) and fat burning (p < 0.001); increased body fat (p = 0.006); decreased muscle mass (p = 0.008); and decreased hydration (p < 0.001). Levels were similar between OTS and NCS, except for worsened fatigue (p < 0.001) and vigour (p = 0.001) in OTS. Reduced calorie intake, worsened sleep, and increased cognitive activity are likely OTS triggers. OTS appears to induce dehydration, increase body fat, decrease libido, and worsen mood.

Hypothalamic-Pituitary-Adrenal (HPA) Axis Functioning in Overtraining Syndrome: Findings from Endocrine and Metabolic Responses on Overtraining Syndrome (EROS)-EROS-HPA Axis

BACKGROUND

Overtraining syndrome (OTS) results from excessive training load without adequate recovery and leads to decreased performance and fatigue. The pathophysiology of OTS in athletes is not fully understood, which makes accurate diagnosis difficult. Previous studies indicate that alterations in the hypothalamus-pituitary-adrenal (HPA) axis may be responsible for OTS; however, the data is not conclusive. This study aimed to compare, through gold standard and exercise-independent tests, the response of the HPA axis in OTS-affected athletes (OTS group) to healthy physically active subjects (ATL group) and healthy non-active subjects (NCS group).

METHODS

Selected subjects were evaluated for cortisol response to a 250-μg cosyntropin stimulation test (CST), cortisol and adrenocorticotropic hormone (ACTH) responses during an insulin tolerance test (ITT), and salivary cortisol rhythm (SCR).

RESULTS

A total of 51 subjects were included (OTS, n = 14; ATL, n = 25; and NCS, n = 12). Cortisol response in the CST was similar among the three groups. Conversely, mean cortisol response during an ITT was significantly higher in ATL (21.7 μg/dL; increase = 9.2 μg/dL) compared to OTS (17.9 μg/dL; 6.3 μg/dL) and NCS (16.9 μg/dL; 6.0 μg/dL) (p ≤ 0.001; p = 0.01). Likewise, median ACTH response during an ITT was significantly higher in ATL (91.4 pg/mL; increase = 45.1 pg/mL) compared to OTS (30.3 pg/mL; 9.7 pg/mL) and NCS (51.4 pg/mL; 38.0 pg/mL) (p = 0.006; p = 0.004). For SCR, mean cortisol 30 min after awakening was significantly higher in ATL (500 ng/dL) compared to OTS (323 ng/dL) and NCS (393 ng/dL) (p = 0.004). We identified the following cutoffs that could help exclude or confirm OTS: cortisol level at 30 min after awakening (exclusion = > 530 ng/dL); cortisol response to ITT (exclusion = > 20.5 μg/dL; confirmation = < 17 μg/dL or increase < 9.5 μg/dL); and ACTH response (exclusion = > 106 pg/mL or increase > 70 pg/mL; confirmation = < 35 pg/mL and increase < 14.5 pg/mL).

CONCLUSION

The findings of the present study showed that healthy athletes disclose adaptions to exercises that helped improve sport-specific performance, whereas this sort of hormonal conditioning was at least partially lost in OTS, which may explain the decrease in performance in OTS.

Hormonal response to a non-exercise stress test in athletes with overtraining syndrome: results from the Endocrine and metabolic Responses on Overtraining Syndrome (EROS) - EROS-STRESS

OBJECTIVES

Overtraining syndrome (OTS) leads to worsened sports performance and fatigue. The pathophysiology of OTS has not been entirely elucidated, and there is a lack of accurate markers for its diagnosis. Changes in hormonal responses implicated in OTS were stimulated by exercise, which has limited their interpretation. Hence, we aimed to evaluate growth hormone (GH) and prolactin responses to a gold-standard and exercise-independent stimulation test, the insulin tolerance test (ITT).

DESIGN

Volunteers were recruited and divided into OTS-affected athletes (OTS), healthy athletes (ATL), and healthy non-active subjects (NCS) groups, after general and specific inclusion and exclusion criteria.

METHODS

We evaluated the responses of growth hormone (GH) and prolactin to the ITT, and compared between groups.

RESULTS

A total of 51 subjects were included (OTS, n=14, ATL, n=25, and NCS, n=12). OTS disclosed significantly lower basal levels of GH (p=0.003) and prolactin (p=0.048), and GH (p=0.001) and prolactin (p<0.001) responses to ITT (p=0.001), compared to ATL, but similar to NCS. OTS showed a later rise in GH levels in response to hypoglycemia, compared to ATL, but not to NCS. We suggest cutoffs for GH and prolactin levels to aid in the diagnosis of OTS.

CONCLUSIONS

OTS-affected athletes show reduced GH and prolactin basal levels and responses to a non-exercise stress test compared to healthy athletes, but not to sedentary subjects.

Diagnosis and prevention of overtraining syndrome: an opinion on education strategies

Overtraining syndrome is a condition of maladapted physiology in the setting of excessive exercise without adequate rest. The exact etiology and pathogenesis are unknown and being investigated. Symptoms are multisystem in nature and often representative of underlying hormonal, immunologic, neurologic, and psychologic disturbances. Unfortunately, systematic review of the literature does not clearly direct diagnosis, management, or prevention. However, given the severity of symptoms and impairment to quality of life, prevention of overtraining syndrome should be considered by all who interact with endurance athletes. This article will provide suggestions for management of at-risk athletes despite absence of validated diagnostic tests and preventative measures.

Can clinicians and scientists explain and prevent unexplained underperformance syndrome in elite athletes: an interdisciplinary perspective and 2016 update

The coach and interdisciplinary sports science and medicine team strive to continually progress the athlete's performance year on year. In structuring training programmes, coaches and scientists plan distinct periods of progressive overload coupled with recovery for anticipated performances to be delivered on fixed dates of competition in the calendar year. Peaking at major championships is a challenge, and training capacity highly individualised, with fine margins between the training dose necessary for adaptation and that which elicits maladaptation at the elite level. As such, optimising adaptation is key to effective preparation. Notably, however, many factors (eg, health, nutrition, sleep, training experience, psychosocial factors) play an essential part in moderating the processes of adaptation to exercise and environmental stressors, for example, heat, altitude; processes which can often fail or be limited. In the UK, the term unexplained underperformance syndrome (UUPS) has been adopted, in contrast to the more commonly referenced term overtraining syndrome, to describe a significant episode of underperformance with persistent fatigue, that is, maladaptation. This construct, UUPS, reflects the complexity of the syndrome, the multifactorial aetiology, and that ‘overtraining’ or an imbalance between training load and recovery may not be the primary cause for underperformance. UUPS draws on the distinction that a decline in performance represents the universal feature. In our review, we provide a practitioner-focused perspective, proposing that causative factors can be identified and UUPS explained, through an interdisciplinary approach (ie, medicine, nutrition, physiology, psychology) to sports science and medicine delivery, monitoring, and data interpretation and analysis.

Prevalence of Depressive Symptoms and Correlating Variables Among German Elite Athletes

Depression among elite athletes is a topic of increasing interest, but empirical data are rare. The present study aimed to provide insight into the prevalence of depressive symptoms among German elite athletes and possible associated factors. In an online survey of 162 athletes, we explored depressive symptoms, chronic stress, coping strategies and stress-recovery states. Results indicated an overall prevalence of 15% for depression among elite athletes (n = 99), and revealed higher levels of depressive symptoms among the individual athletes than the team athletes. Furthermore, correlation analyses showed a significant connection between high levels of depressive symptoms and high levels of chronic stress, negative coping strategies and negative stress-recovery states. Results indicate that the prevalence for depressive symptoms in elite athletes is comparable to that in the general German population. Moreover, exploratory analyses provide first indications of factors associated with depressive symptoms.

Prevention, diagnosis, and treatment of the overtraining syndrome: joint consensus statement of the European College of Sport Science and the American College of Sports Medicine

Successful training not only 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 will eventually lead to an improvement in performance after recovery. When athletes do not sufficiently respect the balance between training and recovery, nonfunctional overreaching (NFOR) can occur. The distinction between NFOR and 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 etiology 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, and others together with identification of initiating events or triggers. In this article, we provide the recent status of possible markers for the detection of OTS. Currently, several markers (hormones, performance tests, psychological tests, and biochemical and immune markers) are used, but none of them meet all the criteria to make their use generally accepted.

The potential role of sports psychology in the obesity epidemic

Sports psychologists play an important role in enhancing performance among athletes. In conjunction with team physicians, they can also shed light on psychological disorders common in athletes, such as mood and eating disorders, and overtraining syndrome. Sports psychologists can also lend their expertise to assist with injury prevention and recovery and compliance issues. Sports psychology has a role in helping to reverse the growing obesity epidemic among school-aged children. These professionals, working with coaches, can increase children's levels of physical activity. Cognitive-behavioral techniques could lead to enhanced enjoyment, increased participation, improved school performance, and a reduction in obesity.

Prevalence of musculoskeletal disorders among Norwegian female biathlon athletes

The purpose was to examine musculoskeletal disorders in Norwegian female biathlon athletes (age ≥ 16), both juniors and seniors. The design was a retrospective cross-sectional study. In all, 148 athletes (79.1%) responded; of these, 118 athletes were 16–21 years (juniors) (77.6%), and 30 athletes were 22 years or older (seniors) (20.3%), and mean age was 19.1. A validated questionnaire was used to collect the data. The prevalence of musculoskeletal disorders was 57.8%. The most affected parts were the knee (23.0% of the total injuries), calf (12.2%), ankle/foot (10.8%), lower back (10.8%), and thigh (10.1%). The disorders resulted in training/competition cessation for 73.5% of athletes, in alternative training for 87.8%. Fifty percent of the athletes had one or several musculoskeletal disorders. Most of the problems occurred preseason, and the duration of symptoms was often prolonged. Few differences between the juniors and seniors were found. This study showed the prevalence of musculoskeletal problems among female biathlon athletes. The results indicate that prevention of lower limb problems must be prioritized, especially during the preseason.

High-performance sports medicine

High performance sports medicine involves the medical care of athletes, who are extraordinary individuals and who are exposed to intensive physical and psychological stresses during training and competition. The physician has a broad remit and acts as a 'medical guardian' to optimise health while minimising risks. This review describes this interesting field of medicine, its unique challenges and priorities for the physician in delivering best healthcare.

Overtraining syndrome: a practical guide

CONTEXT

Fatigue and underperformance are common in athletes. Understanding overtraining syndrome (OTS) is helpful in the evaluation, management, and education of athletes.

EVIDENCE ACQUISITION

Relevant articles in English were searched with OVID (1948-2011) and PubMed using the following keywords: overtraining syndrome, overtraining, overreaching, unexplained underperformance, staleness, pathophysiology, management, treatment, evaluation. Bibliographies were reviewed for additional resources.

RESULTS

OTS appears to be a maladapted response to excessive exercise without adequate rest, resulting in perturbations of multiple body systems (neurologic, endocrinologic, immunologic) coupled with mood changes. Many hypotheses of OTS pathogenesis are reviewed, and a clinical approach to athletes with possible OTS (including history, testing, and prevention) is presented.

CONCLUSIONS

OTS remains a clinical diagnosis with arbitrary definitions per the European College of Sports Science's position statement. History and, in most situations, limited serologies are helpful. However, much remains to be learned given that most past research has been on athletes with overreaching rather than OTS.

Effects of exercise in renal transplant recipients

Even after a successful renal transplantation, the renal transplant recipients (RTRs) keeps on suffering the consequences of the uremic sickness. Cardiovascular risk, work capacity, and quality of life do not improve according to expectations since biological and psychological problems are not completely solved by pharmacological treatment. Furthermore, post-transplant treatment, per se, induces additional problems (i.e., side effects of drugs). It becomes, indeed, very important to insert “non-pharmacological” therapies able to reverse this trend. Exercise may represent an important contribution in the solution of this problem. In fact, many studies have demonstrated, in the last two decades, that physical training is able both, to improve graft function, work capacity and quality of life, and to reduce cardiovascular risk. In conclusion, if the analysis of the available data suggests that an appropriate dose of physical training represent a useful, safe and non-pharmacologic contribution to RTR treatment, it becomes a kidney transplantologist responsibility to introduce exercise in the current therapy of RTRs.

Physical training effects in renal transplant recipients

INTRODUCTION

Several studies demonstrated the benefits of rehabilitation in uraemic patients. This study evaluates physical and psychosocial effects of exercise on renal transplant recipients (RTRs).

PATIENTS AND METHODS

Eight RTRs were evaluated before and after an exercise training consisting of thirty 40-minute sessions, three times a week, performed with the interval training technique.

RESULTS

Hospital Anxiety and Depression Scale (HADS) significantly decreased (p<0.04 and <0.008, respectively). Quality of life mean scores (SF-36 test) significantly increased (p<0.000). No differences were recorded for muscle and fat mass, maximal explosive power of the lower limbs, alkaline and acid phosphatase, parathormone (PTH), myoglobin, lipoprotein-A, glomerular filtration rate (GFR), at rest heart rate, and cardiac troponin. IL-6 decreased from 2.8±0.6 to 1.7±0.5 pg/mL (p<0.01). Resting MAP fell from 112±4 to 99±3 mmHg (p<0.02). The metabolic threshold rose from 33±4 to 43±5% (p<0.033). The blood lactate level at peak exercise increased from 5.2±0.9 to 6.2±0.7 mmol/L (p<0.012). The maximum oxygen uptake increased from 1200±210 to 1359±202 mL/min (p<0.05), iso-load oxygen uptake decreased from 1110±190 to 1007±187 mL/min (p<0.034). The maximum working capacity increased from 90±14 to 115±15 watts (p<0.000).

CONCLUSION

This study suggests that an appropriate dose of physical training is a useful, safe and non-pharmacologic contribution to RTR treatment.

Effects of chitooligosaccharide lactate salt on sleep deprivation-induced fatigue in mice

Chitooligosaccharides (COS), oligosaccharides composed of two to seven glucosamine residues, are known to exhibit various biological activities. In this study, we investigated the effects of COS in an in vivo mouse sleep deprivation-induced fatigue model in an effort to develop a functional food with anti-fatigue efficacy. Male Balb/c mice were orally administered 500 mg (kg d)(-1) of COS lactate or COS HCl for 2 weeks, and severe fatigue was induced by sleep deprivation. To evaluate the extent of fatigue, the swimming time, representing the immobility time, was measured in a forced swim test. As a result, oral intake of COS lactate-manifested anti-fatigue effects could be observed by the attenuation of fatigue-induced body weight loss and shorter immobility period. In addition, COS lactate was shown to alleviate the fatigue-induced increase in cortisol and lipid peroxidation and a decrease in superoxide dismutase (SOD) activity. Of particular note, the oral administration of COS lactate increased the mitochondrial membrane potential and the mitochondrial number significantly, indicating that COS lactate may enhance mitochondrial function. In support of this, COS lactate increased the expression of peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha) and cytochrome c (Cyt C) mRNA, indicating that it may increase mitochondrial biogenesis. These results suggest that COS lactate can be an effective anti-fatigue functional food, and this anti-fatigue effect may result from, at least in part, the enhancement of mitochondrial biogenesis and the inhibition of free radical generation.

Fatigue management in the preparation of Olympic athletes

Fatigue is often a consequence of physical training and the effective management of fatigue by the coach and athlete is essential in optimizing adaptation and performance. In this paper, we explore a range of practical and contemporary methods of fatigue management for Olympic athletes. We assesses the scientific merit of methods for monitoring fatigue, including self-assessment of training load, self-scored questionnaires, and the usefulness of saliva and blood diagnostic markers for indicating fatigued and under-recovered athletes, effective nutrition and hydration strategies for optimizing recovery and short-term recovery methods. We conclude that well-accepted methods such as sufficient nutrition, hydration, and rest appear to be the most effective strategies for optimizing recovery in Olympic athletes.

The human genome and sport, including epigenetics, gene doping, and athleticogenomics

Hugh Montgomery's discovery of the first of more than 239 fitness genes together with rapid advances in human gene therapy have created a prospect of using genes, genetic elements, and cells that have the capacity to enhance athletic performance (to paraphrase the World Anti-Doping Agency's definition of gene doping). This brief overview covers the main areas of interface between genetics and sport, attempts to provide a context against which gene doping may be viewed, and predicts a futuristic legitimate use of genomic (and possibly epigenetic) information in sport.

Absence of the predisposing factors and signs and symptoms usually associated with overreaching and overtraining in physical fitness centers

OBJECTIVE

The aim of this study was to evaluate the occurrence of the well-known predisposing factors and signs and symptoms usually associated with either overreaching or overtraining syndrome in physical fitness centers in São Paulo City, Brazil.

METHOD

A questionnaire consisting of 13 question groups pertaining to either predisposing factors (1-7) or signs and symptoms (8-13) was given to 413 subjects. The general training schedule of the volunteers was characterized by workout sessions of 2.18 ± 0.04 h for a total of 11.0 ± 0.3 h/week for 33 ± 2 months independent of the type of exercise performed (walking, running, spinning, bodybuilding and stretching). A mean score was calculated ranging from 1 (completely absent) to 5 (severe) for each question group. A low occurrence was considered to be a question group score lower than 4, which was observed in all 13 question groups.

RESULTS

The psychological evaluation by POMS Mood State Questionnaire indicated a normal non-inverted iceberg. The hematological parameters, creatine kinase activity, cortisol, total testosterone and free testosterone concentrations were within the normal ranges for the majority of the volunteers selected for this analysis (n = 60).

CONCLUSION

According to the questionnaire score analysis, no predisposing factors or signs and symptoms usually associated with either overreaching or overtraining were detected among the members of physical fitness centers in São Paulo City, Brazil. This observation was corroborated by the absence of any significant hematological or stress hormone level alterations in blood analyses of the majority of the selected volunteers (n = 60).

Evaluation and opportunities in overtraining approaches

Overtraining (OT) as a sports phenomenon can be caused by stressors on various levels (physical, emotional, psychological, and social) and evokes responses on these levels. This study evaluated research and new opportunities in the field of OT by introducing an integrated multidisciplinary approach, based on the single and multistressors approach. The single stressor approach focuses on the training load-recovery imbalance, which results in a stagnating performance, excluding the etiology by nonsport-related factors. The multistressors approach includes all factors as relevant in the etiology of a stagnating performance. In future studies on OT an integrative approach should not only highlight changes in training regimes and specific responses to training stressors but also focus on the role of training-related recovery, the impact of stressors, and personality factors influencing stress appraisal. This will provide a better insight into the etiology and consequences of OT necessary for prevention and treatment in sport practice, and enhance the focus on adequate recovery (good sleep, sufficient rest periods) and athletes' stress-related responses.

Treating Chronic Fatigue states as a disease of the regulation of energy metabolism

Chronic Fatigue Syndrome is a physiological state in which the patient feels high levels of fatigue without an obvious organic cause, which affects around 1 in 400 people in the developed world. A wide range of causes have been suggested, including immune or hormonal dysfunction, viral or bacterial infection, and psychological somatization. It is likely that several causes are needed to trigger the disease, and that the triggers are different from the mechanisms that maintain fatigue over months or years. Many treatments have been tested for CFS, with very limited success - a programme of combined CBT and graded exercise shows the most effect. I suggest that patients with CFS have a reduced ability to increase mitochondrial energy production when exertion requires it, with fewer mitochondria that are each more efficient, and hence nearer to their maximum energy output, than normal. A range of indirect evidence suggests that the renin-angiotensin system stimulates mitochondrial responsiveness and reduces mitochondrial efficiency: chronic under-stimulation of this system could contribute to CFS aetiology. If correct, this means that CFS can be successfully treated with RAS agonists (eg angiotensin mimetics), or adrenergic agonists. It also suggests that there will be a positive link between the use of adrenergic- and RAS-blocking drugs and CFS incidence, and a negative link between adrenergic agonist use and CFS.

Psychobiological mechanisms of exercise dependence

Exercise dependence (ED) is characterised by an obsessive and unhealthy preoccupation with exercise. Previous research has focused largely on identifying behavioural aspects of ED, although the biological mechanisms remain unknown and are under researched. We review various ED hypotheses including affect regulation, anorexia analogue, sympathetic arousal and beta-endorphin. We also present a novel hypothesis pertaining to ED and interleukin (IL)-6, which combines previous hypotheses with literature from the field of psycho-neuroimmunology. We explore the notion that IL-6 provides a link from the periphery to the brain, which may mediate the underlying features of ED. We propose a conceptual model indicating that, in individuals prone to ED, exercise results in a transient reduction in negative affect, but concurrently results in excessive production of IL-6 and the activation of neuroendocrine pathways, which are associated with behavioural and psychological disturbances of exercise withdrawal. Our intention is for this model to serve as a basis for further research in the area of ED, which may eventually lead to the development of successful treatment strategies. Recent developments in methods to reliably assess these biological markers from blood and saliva samples should encourage such research to be undertaken in exercise settings.

Elevated plasma interleukin-6 levels in trained male triathletes following an acute period of intense interval training

The aim of the present study was to investigate possible changes in the plasma IL-6 levels, subjective reporting of sources and symptoms of stress and the innate immune system in response to an acute period of intensified run training in highly trained endurance athletes. Eight healthy endurance trained male subjects (mean +/- SD age 23 +/- 2 years, VO(2max) 64.8 +/- 2.6 ml kg(-1) min(-1), mass 77.1 +/- 2.9 kg) completed the study which took place over a 4 week period. In weeks 2 and 3, in addition to their normal endurance training, subjects completed interval-training run sessions on three successive days. Saliva and venous blood samples were taken at the end of each week. Blood samples were analysed for leukocyte counts; neutrophil function; plasma IL-6; creatine kinase activity; and cortisol. Symptoms and sources of stress were assessed by questionnaire. Plasma IL-6 and creatine kinase activity were elevated following intensified training. Neutrophil function was reduced but total leukocyte and neutrophil counts, plasma cortisol and salivary IgA remained unchanged. There was a worsening in symptoms of stress despite there being no significant change in the sources of stress during intensified training. In conclusion, an acute period of intensified training can induce a suppression of the innate immune system and a chronic elevation in IL-6. This was associated with an increase in fatigue and generalised malaise which lends support to the recent cytokine theories of unexplained, underperformance syndrome.

β2-Adrenergic receptor downregulation and performance decrements during high-intensity resistance exercise overtraining

Previous research on overtraining due to excessive use of maximal resistance exercise loads [100% 1 repetition maximum (1 RM)] indicates that peripheral muscle maladaptation contributes to overtraining-induced performance decrements. This study examined the cellular and molecular responses of skeletal muscle to performance decrements due to high-relative-intensity (%1 RM) resistance exercise overtraining. Weight-trained men were divided into overtrained (OT, n = 8) and control (Con, n = 8) groups. The OT group performed 10 x 1 at 100% 1 RM daily for 2 wk, whereas the Con group performed normal training 2 days/wk. Muscle biopsies from the vastus lateralis muscle, voluntary static and dynamic muscle performances, and nocturnal urinary epinephrine were assessed before (pre) and after (post) overtraining. Overtraining occurred as indicated by a decrease in 1-RM strength for the OT group (mean +/- SE; OT pre = 159.3 +/- 10.1 kg, OT post = 151.4 +/- 9.9 kg, Con pre = 146.0 +/- 12.9 kg, Con post = 144.9 +/- 13.3 kg), as well as a 36.3% decrease in mean power at 100% 1-RM loads. Normal training could be resumed only after 2-8 wk of training cessation. Muscle beta(2)-adrenergic receptor (beta(2)-AR; fmol/mg protein) density significantly decreased by 37.0% for the OT group and was unchanged for the Con group (-1.8%). Nocturnal urinary epinephrine for the OT group increased by 49%, although this was not significant (effect size = 0.42). The ratio of nocturnal urinary epinephrine to beta(2)-AR density suggested a decreased beta(2)-AR sensitivity for the OT group (2.4-fold increase). Overtraining occurred based on decreased muscular force and power. Desensitization of the beta(2)-AR system suggests that this may be an important contributor to performance decrements due to excessive use of maximal resistance exercise loads.

Efeito de diferentes protocolos de treinamento de força sobre parâmetros morfofuncionais, hormonais e imunológicos

O objetivo do estudo foi examinar a influência de dois diferentes protocolos de treinamento de força sobre parâmetros antropométricos (peso, IMC, massa gorda), funcionais (teste de 1-RM e teste de repetições máximas) e relacionados ao sistema endócrino (concentração de testosterona e de cortisol) e ao sistema imunológico (concentração de glutamina e de IgG). Participaram do estudo 12 homens treinados (27,4 ± 4,8 anos). Esses indivíduos foram aleatoriamente divididos em dois grupos, que posteriormente foram submetidos a dois protocolos de treinamento distintos: Múltiplas séries (MS) e Tri-set (TS). Amostras de sangue foram coletadas antes e depois de uma sessão de exercício de força, no início e no final do período de oito semanas de treinamento. Não foram observadas alterações nos parâmetros morfo-funcionais (com exceção do teste de repetições máximas para o agachamento). Com relação aos parâmetros endócrinos, foi observado que o TS provocou aumento significativo do cortisol, imediatamente após a sessão de treino, tanto no início como no final das oito semanas (p < 0,05). Ao observar o comportamento da relação testosterona para cortisol (T:C), pode-se notar um marcante aumento no grupo submetido ao protocolo MS após oito semanas de treinamento (p < 0,05). Com relação aos parâmetros imunológicos, não foi observada alteração na concentração de imunoglobulina G. A concentração de glutamina sofreu decréscimo após oito semanas em ambos os grupos. Esse decréscimo foi mais acentuado no grupo TS (p < 0,05). Os resultados obtidos sugerem que o método TS impôs maior estresse ao organismo. Além disso, os dados também indicam que o protocolo MS promove um ambiente mais propício ao anabolismo, após oito semanas de treinamento. Entretanto, ambos os métodos falharam em promover alterações significativas nos parâmetros morfofuncionais.

Physical activity and mental health: the association between exercise and mood

Physical activity is an important public health tool used in the treatment and prevention of various physical diseases, as well as in the treatment of some psychiatric diseases such as depressive and anxiety disorders. However, studies have shown that in addition to its beneficial effects, physical activity can also be associated with impaired mental health, being related to disturbances like "excessive exercise" and "overtraining syndrome". Although the number of reports of the effects of physical activity on mental health is steadily increasing, these studies have not yet identified the mechanisms involved in the benefits and dangers to mental health associated with exercise. This article reviews the information available regarding the relationship between physical activity and mental health, specifically addressing the association between exercise and mood.

Hormonal and Metabolic Adaptation in Professional Cyclists During Training

The aim of this study was to examine hormonal and metabolic changes in a group of 18 professional male cyclists ([Formula: see text]69.9 [95% CI 64.9 to 74.9] m L kg−1ùmin−1) during two successive periods of adapted intensive training. The second training period included 4 days of cycling competition. Intensity was increased while volume was decreased in the second training. Anthropometric data were collected before and at the end of the two training periods. Venous blood samples were taken in a basal state before the two training sessions and after each training session. Serum concentrations of cortisol (C), testosterone (T), dehydroepiandrosterone sulfate (DHEAs), and catecholamines were determined as well as branched-chain amino acids (valine, leucine, isoleucine) (BCAA) and free fatty acids (FFAs). At the end of the two training periods, the subjects lost fat mass whereas mean body mass was unchanged. The T/C ratio was reduced transiently after the first training session (45.90%), while DHEAs/C remained unchanged. T/C and DHEAs/C were significantly increased after the second training session compared to the first (48.40 and 97.18%, respectively). Catecholamines and FFAs were unchanged. The significant increase in BCAA levels after the second training session was of note as it might constitute a "store shape" of amino acids in anticipation of future intense training loads. Based on the responses of testosterone, DHEAs, and cortisol, and on the training-induced increase in BCAA, there appeared to be hormonal and metabolic adaptation despite the inherent psychological stress of competition. Key words: cycling training, cortisol, testosterone, DHEAs, amino acids

Elucidating the unexplained underperformance syndrome in endurance athletes : the interleukin-6 hypothesis

The unexplained underperformance syndrome (UPS), previously known as the overtraining syndrome (OTS), has been defined as a persistent decrement in athletic performance capacity despite 2 weeks of relative rest. It has been proposed that UPS may be caused by excessive cytokine release during and following exercise causing a chronic inflammatory state and 'cytokine sickness'. This article extends that hypothesis by proposing that time-dependent sensitisation could provide a model through which the aetiology of UPS may be explained. In this model, the principal abnormal factors in UPS are an increased production of and/or intolerance to interleukin (IL)-6 during exercise. Strategies to attenuate the IL-6 response to exercise that may also reduce an athlete's susceptibility to UPS are proposed.

Glutamine supplementation in vitro and in vivo, in exercise and in immunodepression

In situations of stress, such as clinical trauma, starvation or prolonged, strenuous exercise, the concentration of glutamine in the blood is decreased, often substantially. In endurance athletes this decrease occurs concomitantly with relatively transient immunodepression. Glutamine is used as a fuel by some cells of the immune system. Provision of glutamine or a glutamine precursor, such as branched chain amino acids, has been seen to have a beneficial effect on gut function, on morbidity and mortality, and on some aspects of immune cell function in clinical studies. It has also been seen to decrease the self-reported incidence of illness in endurance athletes. So far, there is no firm evidence as to precisely which aspect of the immune system is affected by glutamine feeding during the transient immunodepression that occurs after prolonged, strenuous exercise. However, there is increasing evidence that neutrophils may be implicated. Other aspects of glutamine and glutamine supplementation are also addressed.

Biochemical aspects of overtraining in endurance sports : the metabolism alteration process syndrome

Recent studies have shown that endurance overtraining could result from successive and cumulative alterations in metabolism, which become chronic during training. The onset of this process is a biochemical alteration in carbohydrate (saccharide) metabolism. During endurance exercises, the amount of saccharide chains from two blood glycoproteins (alpha(2)-macroglobulin and alpha(1)-acid glycoprotein) was found to have decreased, i.e. concentrations of these proteins remained unchanged but their quality changed. These saccharide chains were probably used for burning liver glycogen stores during exercise. This step was followed by alterations in lipid metabolism. The most relevant aspect of this step was that the mean chain length of blood fatty acids decreased, i.e. the same amount of fatty acids were found within the blood, but overtrained individuals presented shorter fatty acids than well-trained individuals. This suggests that alterations appeared in the liver synthesis of long-chain fatty acids or that higher peroxidation of blood lipoparticles occurred. For the final step of this overtraining process, it was found that these dysfunctions in carbohydrate/lipid metabolism led to the higher use of amino acids, which probably resulted from protein catabolism. The evolution of three protein concentrations (alpha(1)-acid glycoprotein, alpha(2)-macroglobulin and IgG(3)) correlated with this amino acid concentration increase, suggesting a specific catabolism of these proteins. At this time only, overtraining was clinically diagnosed through conventional symptoms. Therefore, this process described successive alterations in exercise metabolism that shifted from the main energetic stores of exercise (carbohydrates and lipids) towards molecular pools (proteins) normally not substantially used for the energetic supply of skeletal muscles. Now, a general biochemical model of the overtraining process may be proposed which includes most of the previously identified metabolic hypotheses.