Post by RUBICON19 on Dec 14, 2008 14:05:15 GMT -5
Overtraining Syndrome
What trainers need to look for in their high-achieving athletes.
By Jodai Saremi , DPM
In the wake of the Olympics, thousands of athletes returned home to throw themselves, with renewed vigor, into their workout routines, hoping to try again for the elusive Gold. This time around, they just weren't fast enough, strong enough or flexible enough to win. However, a percentage of these individuals may have suffered from a syndrome that affects many athletes some time in their career, from team sports to individual competitions. With prolonged training stresses and inadequate rest and recovery periods, overtraining syndrome (OTS) may have caused competitors' performances to come up short instead of propelling them into fame. Over 60 percent of distance runners, 50 percent of professional soccer players (in a five-month season) and 33 percent of basketball players (in a six-week training camp) have been reported to exhibit signs
and symptoms of OTS.1 OTS is a complex group of symptoms that is characterized by an athlete who has been training extremely hard and then suddenly experiences underperformance or burnout. The underperformance persists despite a period of recovery lasting weeks or months.2
The British Olympic Association met in 1999 to redefine the overtraining syndrome as the "unexplained underperformance syndrome."3 They distinguished it from over-reaching, which is due to short-term overtraining at high intensity and is resolved with two weeks of relative rest. They also stated that there are different presentations for endurance athletes (like marathon runners versus sprint) and power athletes (such as weightlifters, gymnasts and ski jumpers). In their assessment, evidence showed that endurance athletes experienced fatigue and underperformance with "secondary changes in mood," while sprinters complained first of feeling burned out and depressed and then had changes in performance.
OTS may be considered a "systemic overuse injury." 4,5 Many studies point to changes in hormone levels, brain neurotransmitters and autonomic nerve imbalances. But there are subjective symptoms that are more difficult to measure, such as sore muscles, mood disturbances, changes in sleep quality, loss of competitive drive, loss of libido, headaches, excessive sweating, loss of appetite and nausea.3,5 There may also be loss of muscle strength, coordination and maximum working capacity, an increase in the number of minor injuries and muscle strains, an elevated resting heart rate, elevated blood pressure and an increased frequency in upper respiratory tract infections. 5 Because of the suppressed immune system functions, the diagnosis of OTS requires that disease be ruled out. Therefore, all athletes with signs and symptoms of OTS should have a thorough history and physical examination performed by a doctor.
Although the list of signs and symptoms for OTS is extensive, scientists and physicians struggle to determine the cause or etiology of OTS. The only certain sign is a plateau or decrease in performance during competition or training. As trainers, it is important to acknowledge that elite athletes will, at some point in their careers, experience OTS and it is your job to help them overcome that obstacle and return to achieving physical success.
Physical Injuries
Musculoskeletal injuries most often sustained in this syndrome are related to overuse: the high frequency, high intensity exercises performed over a long duration produce excessive, repeated stress on one area of the body. The tissues fail due to "repeated episodes of microtrauma that cause disease."5
These injuries are chronic and may include muscle strains, sprains, subluxation, dislocation, muscle tears, tendinopathy, synovitis, bursitis, contusions and joint dysfunctions.4,5 For example, tennis players and golfers may complain of "tennis elbow" or "golfer's elbow," where movement of the extensor and flexor muscles, respectively, causes burning pain in the arm and wrists. Patellofemoral pain may occur in athletes who have an overly developed vastus lateralis, which pulls the patella out of alignment, while patellar tendonitis occurs when there is a weak quadricep muscle or overuse due to jumping. Iliotibial band (ITB) friction syndrome is the most common cause of lateral knee pain in runners and results from microtrauma to the ITB as it slides over the lateral femoral condyle.4 Shin splints are a common injury in runners where the athlete has pain in the anterior lower leg due to overuse of the anterior tibialis, improper training progression or inherent foot pathomechanics. In the forefoot, excessive forces on the metatarsal heads can result in metatarsalgia and/or plantar fascitis and even stress fractures.
A note on stress fractures: often the area of fracture doesn't show typical signs of bruising or swelling and the pain persists only during exercise. When the person is resting, the discomfort is relieved. There is, however, precise pain that can be elicited with one finger pressing on the fractured bone. Because the pain is intermittent, athletes may let the injury go for weeks or months before seeking medical attention.
Generally speaking, when athletes have persistent pain with little change for months, whether due to the fact that they won't rest or they try to exercise through the pain, at some point the tissues will fail. They will sustain overuse injuries that are guaranteed to take them out of commission for a significantly longer amount of time than if they had paid attention to the pain initially and rested to give the body time to heal.
Hormonal Responses
OTS is the body's attempt to cope with psychological and non-psychological stress, so when the body has been under stress for an extended period of time, the stage of exhaustion is reached. The athlete feels that he or she just cannot work any more or that energy is tapped out. At this point, adrenalin, noradrenaline and cortisol, hormones whose chief function is to redistribute metabolic fuels at different rates and enhance the responsiveness of the cardiovascular system, are mobilized.1 Additionally, local inflammatory responses (in muscles or joints, for example) become systemic as cytokines are released outside and inside the brain. Cytokines, in turn influence hypothalamus-pituitaryadrenal function, which is responsible for producing the aforementioned adrenalin, noradrenaline and cortisol.6 The feedback loop is complete, at least at this level.
Muscular fatigue is attributed to a metabolic endpoint where concentrations of muscle glycogen and plasma glucose are used up; at the same time, levels of free fatty acids in the blood increase as the body tries to supply energy required for the work being done.7,8 These processes occur peripherally in the body, but central fatigue also occurs in the brain, involving the neurotransmitters serotonin, dopamine and noradrenaline.1,7 The brain and the muscles are connected biochemically through feedback between the levels of free fatty acids and amino acids: when the body uses up its sugar energy stores, fats and proteins are then liberated for use as energy.8,9 The brain uses amino acids from the liberated proteins to make neurotransmitters, which in turn help regulate how we feel. The serotonergic system modulates mood, emotion, sleep and appetite, thereby controlling behavior and physiologic functions.8 Increases in the ratio of serotonin to dopamine cause feelings of lethargy and the loss of drive. This leads to a reduction of motor unit recruitment in the muscles in an effort to conserve energy until more glucose is ingested and/or introduced to the system. Fatigue is an integrated phenomenon, with interactions between central and peripheral factors.
Diagnosis Problems
Although OTS in athletes has been documented anecdotally for years by coaches, scientists have been hard-put to come up with repeatable tests that consistently identify chemical or physical changes in these athletes' bodies.10 A number of the experiments conducted used small study groups and did not induce a state of true "overtraining" because the athletes were forced to increase intensity over a short period of time to fall within the time boundaries of the experiment (12 weeks, for example).11 The work with biomarkers for oxidative stress, biochemical alterations in metabolic processes and endocrine dysfunction all show much promise in explaining how and why overtraining causes fatigue and underperformance. 1,9,11 But more questions, than answers, have been raised, many of which have to do with conducting well-controlled experiments on larger samples of athletes.
Practical Applications
While it isn't necessary to hold a degree in biochemistry or neuroscience to train athletes safely, a basic understanding of possible causes for OTS may help in formulating a plan when an athlete does begin to complain of feeling burned out and weak, even after months of diligent training. There may not be a hallmark set of clinical markers yet that can be tested in the blood to make the specific diagnosis of OTS, but by excluding other illnesses through a thorough history and physical examination, it's possible to make a pretty good educated guess if an individual is suffering from OTS.
The athlete's diet must be examined for caloric intake, specifically in the form of carbohydrates. Anyone ingesting too few calories and not enough readily available calories in the form of complex carbs will exhibit signs of fatigue and weakness and even mood disturbances. Blood tests for anemia, hypothyroidism, Lyme disease and other infections may show organic causes of fatigue and weakness.1
In light of the myriad of influences on health, it is prudent to analyze how often an athlete is eating, what his/her sources of nutrients are and whether s/he is giving himself adequate rest periods between bouts of exercise. The best way is to start with a log.5,10
Keep a training log with notes on both subjective and objective findings. It is common sense to record weight, speed, types of exercises, number of reps, heart rate and dietary intake, but also have the athlete take notes on feelings after each workout, rates of perceived exertion and enthusiasm or tiredness. If the pace slows, a resting heart rate increases or there are consistent complaints of fatigue, the athlete may be overtraining. Before starting any extreme conditioning program, sport-specific exercise testing conducted to exhaustion provides a baseline against which future performance can be judged.4 Although this requires discipline, planning and long-term commitment to the athlete, personal trainers and coaches who keep good, accurate records may save themselves from losing a full season of competition from valuable, talented athletes.
Treatment
Avoid OTS by using cyclical training and periodization.1,5 Alternate hard, easy and moderate periods of training. This should give the body enough time to recuperate from very strenuous training sessions: tissues need time to heal. Also, encourage good sleep habits. Most healing occurs during sleep. Sleep is important for brain function, too.
Keep boredom from occurring with cross training.1 While a variety of exercises will ensure that the same joints and muscles aren't being used over and over, it also forces the athlete to think differently.
When the athlete does present injuries or soreness, rest and physical therapy, including massage, are recommended. Depending on the severity of the injuries, rest can be "active," if the exercise avoids using the injured body parts, just to keep the athlete psychologically in the game.1,5,12
To help facilitate recovery of energy and healing of tissues, nutritional intake must be adjusted with the guidance of a licensed nutritionist or physician who may recommend vitamins and minerals, such as B vitamins, calcium, potassium, magnesium and vitamin C, depending on the acuteness of the symptoms and injuries.
The hydration status of the athlete must also be taken into consideration, not only acutely during exercise, but when recovering during the rest period. Dehydration has been shown to decrease one¿repetition maximum performance and anaerobic power in the upper and lower extremities, and it reduces aerobic endurance. 13,14,15 Adequate fluid ingestion favorably influences athletic performance by maintaining stroke volume, cardiac output, serum osmolality and sodium concentration.16 However, there has been no connection proven between hydration and muscle cramps or soreness.17,18
Conclusion
Inconsistent changes have been documented in the areas of physiologic functioning, impairments in psychological processing, immunologic dysfunction and biochemical abnormalities in the diagnosis of OTS. Although the cause or etiology of this failure to perform remains difficult to pinpoint, studies and experiments examining the neuro-endocrine-immune dysregulation resulting in the stress-related disorder, OTS, have only just begun to scratch the surface.6
Jodai Saremi, DPM, is AFAA certified in group exercise and personal training. She is a contributing editor for American Fitness and enjoys writing about a variety of health and fitnessrelated subjects.
REFERENCES:
Armstrong, L.E. and VanHeest, J.L. "The Unknown Mechanism of the Overtraining Syndrome. Clues from Depression and Psychoneuroimmunology." Sports Medicine, 32, No. 3 (2002): 185-209.
Urhausen, A. and Kindermann, W. "Diagnosis of Overtraining: What Tools Do We Have ?" Sports Medicine, 32, No. 2 (2002): 95-102.
Budgett, R., et al. "Redefining the Overtraining Syndrome as the Unexplained Underperformance Syndrome." British Journal of Sports Medicine, 34, No. 1 (2000): 67-68.
Cosca, D.D. and Nava zio, F. "Common Problems in Endurance Athletes." American Family Physician, 76, No. 2 (July 2007): 237-44.
Yoke , M. Personal Fitness Training Theory and Practice. Sherman Oaks, Calif.: Aerobics and Fitness Association of America, 2006.
Angeli, A., et al. "The Overtraining Syndrome in Athletes: A Stress-Relate d Disorder." Journal of Endocrinological Investigation, 27, No. 6 (June 2004): 603-12.
Meeuse n, R., et al. "Central Fatigue : The Serotonin Hypothesis and Beyond." Sports Medicine, 36, No. 10 (2006): 881-909.
Meeuse n, R., et al. "Brain Neurotransmitters in Fatigue and Overtraining." Applied Physiology, Nutrition and Metabolism, 32, No. 5 (October 2007): 857-64.
Petibois, C., et al. "Biochemical Aspects of Overtraining in Endurance Sports: The Metabolis mAlteration Process Syndrome." Sports Medicine, 33, No. 2 (2003): 83-94.
Halson, S.L. and Jeukendrup, A.E. "Does Overtraining Exist? An Analysis of Overreaching and Overtraining Research." Sports Medicine, 34, No. 14 (2004): 967-81.
Ma rgonis, K., et al. "Oxidative Stress Biomarkers Responses to Physical Overtraining: Implications for Diagnosis." Free Radical Biology and Medicine, 43, No. 6 (September 2007): 901-10.
Peluso, M.A. and Guerra de Andrade, L.H. "Physical Activity and Mental Health : The Association Between Exercise and Mood." Clinics, 60, No. 1 (February 2005): 61-70.
Schoffstall , J.E., et al. "Effects of Dehydration and Rehydratio n on the One-Repetition Maximum Bench Press of Weight-Trained Males." Journal of Strength Conditioning Research, 15, No. 1 (February 2001): 102-08.
Jones, L.C., et al. "Active Dehydration Impairs Upper and Lower Body Anaerobic Muscular Power." Journal of Strength Conditioning Research, 22, No. 2 (March 2008): 455-63.
Barr, S.I. "Effects of Dehydratio n on Exercise Performance." Canadian Journal of Applied Physiology, 24, No. 2 (April 1999): 164-72.
Noakes , T.D. "Fluid Replacement During Exercise." Exercise & Sports Sciences Reviews, 21 (1993): 297-330.
Schwellnus, M.P., Derman, E.W. and Noakes, T.D. "Aetiology of Skeletal Muscle `Cramps' During Exercise: A Novel Hypothesis." Journal of Sports Science, 15, No. 3 (June 1997): 277-85.
Schwellnus, M.P., et al. "Serum Electrolyte Concentrations and Hydratio n Status are not Associated with Exercise Associate d Muscle Cramping in Distance Runners." British Journal of Sports Medicine, 38, No. 4 (August 2004): 488-92.
© 1995-2008 Aerobics and Fitness Association of America
AFAA Certification Testing Accredited by Vital Research.
Fitness Triage®, TeleFitness®, Nutrition Gets Personal™,
Exercise Gets Personal™ and Fitness Gets Personal®
are protected by U.S. patent.
15250 Ventura Blvd., Suite 200, Sherman Oaks, CA 91403.
1-877-YOUR-BODY (1-877-968-7263)
Mon-Fri 6:30am-6:30pm Sat 7am-1pm PST
What trainers need to look for in their high-achieving athletes.
By Jodai Saremi , DPM
In the wake of the Olympics, thousands of athletes returned home to throw themselves, with renewed vigor, into their workout routines, hoping to try again for the elusive Gold. This time around, they just weren't fast enough, strong enough or flexible enough to win. However, a percentage of these individuals may have suffered from a syndrome that affects many athletes some time in their career, from team sports to individual competitions. With prolonged training stresses and inadequate rest and recovery periods, overtraining syndrome (OTS) may have caused competitors' performances to come up short instead of propelling them into fame. Over 60 percent of distance runners, 50 percent of professional soccer players (in a five-month season) and 33 percent of basketball players (in a six-week training camp) have been reported to exhibit signs
and symptoms of OTS.1 OTS is a complex group of symptoms that is characterized by an athlete who has been training extremely hard and then suddenly experiences underperformance or burnout. The underperformance persists despite a period of recovery lasting weeks or months.2
The British Olympic Association met in 1999 to redefine the overtraining syndrome as the "unexplained underperformance syndrome."3 They distinguished it from over-reaching, which is due to short-term overtraining at high intensity and is resolved with two weeks of relative rest. They also stated that there are different presentations for endurance athletes (like marathon runners versus sprint) and power athletes (such as weightlifters, gymnasts and ski jumpers). In their assessment, evidence showed that endurance athletes experienced fatigue and underperformance with "secondary changes in mood," while sprinters complained first of feeling burned out and depressed and then had changes in performance.
OTS may be considered a "systemic overuse injury." 4,5 Many studies point to changes in hormone levels, brain neurotransmitters and autonomic nerve imbalances. But there are subjective symptoms that are more difficult to measure, such as sore muscles, mood disturbances, changes in sleep quality, loss of competitive drive, loss of libido, headaches, excessive sweating, loss of appetite and nausea.3,5 There may also be loss of muscle strength, coordination and maximum working capacity, an increase in the number of minor injuries and muscle strains, an elevated resting heart rate, elevated blood pressure and an increased frequency in upper respiratory tract infections. 5 Because of the suppressed immune system functions, the diagnosis of OTS requires that disease be ruled out. Therefore, all athletes with signs and symptoms of OTS should have a thorough history and physical examination performed by a doctor.
Although the list of signs and symptoms for OTS is extensive, scientists and physicians struggle to determine the cause or etiology of OTS. The only certain sign is a plateau or decrease in performance during competition or training. As trainers, it is important to acknowledge that elite athletes will, at some point in their careers, experience OTS and it is your job to help them overcome that obstacle and return to achieving physical success.
Physical Injuries
Musculoskeletal injuries most often sustained in this syndrome are related to overuse: the high frequency, high intensity exercises performed over a long duration produce excessive, repeated stress on one area of the body. The tissues fail due to "repeated episodes of microtrauma that cause disease."5
These injuries are chronic and may include muscle strains, sprains, subluxation, dislocation, muscle tears, tendinopathy, synovitis, bursitis, contusions and joint dysfunctions.4,5 For example, tennis players and golfers may complain of "tennis elbow" or "golfer's elbow," where movement of the extensor and flexor muscles, respectively, causes burning pain in the arm and wrists. Patellofemoral pain may occur in athletes who have an overly developed vastus lateralis, which pulls the patella out of alignment, while patellar tendonitis occurs when there is a weak quadricep muscle or overuse due to jumping. Iliotibial band (ITB) friction syndrome is the most common cause of lateral knee pain in runners and results from microtrauma to the ITB as it slides over the lateral femoral condyle.4 Shin splints are a common injury in runners where the athlete has pain in the anterior lower leg due to overuse of the anterior tibialis, improper training progression or inherent foot pathomechanics. In the forefoot, excessive forces on the metatarsal heads can result in metatarsalgia and/or plantar fascitis and even stress fractures.
A note on stress fractures: often the area of fracture doesn't show typical signs of bruising or swelling and the pain persists only during exercise. When the person is resting, the discomfort is relieved. There is, however, precise pain that can be elicited with one finger pressing on the fractured bone. Because the pain is intermittent, athletes may let the injury go for weeks or months before seeking medical attention.
Generally speaking, when athletes have persistent pain with little change for months, whether due to the fact that they won't rest or they try to exercise through the pain, at some point the tissues will fail. They will sustain overuse injuries that are guaranteed to take them out of commission for a significantly longer amount of time than if they had paid attention to the pain initially and rested to give the body time to heal.
Hormonal Responses
OTS is the body's attempt to cope with psychological and non-psychological stress, so when the body has been under stress for an extended period of time, the stage of exhaustion is reached. The athlete feels that he or she just cannot work any more or that energy is tapped out. At this point, adrenalin, noradrenaline and cortisol, hormones whose chief function is to redistribute metabolic fuels at different rates and enhance the responsiveness of the cardiovascular system, are mobilized.1 Additionally, local inflammatory responses (in muscles or joints, for example) become systemic as cytokines are released outside and inside the brain. Cytokines, in turn influence hypothalamus-pituitaryadrenal function, which is responsible for producing the aforementioned adrenalin, noradrenaline and cortisol.6 The feedback loop is complete, at least at this level.
Muscular fatigue is attributed to a metabolic endpoint where concentrations of muscle glycogen and plasma glucose are used up; at the same time, levels of free fatty acids in the blood increase as the body tries to supply energy required for the work being done.7,8 These processes occur peripherally in the body, but central fatigue also occurs in the brain, involving the neurotransmitters serotonin, dopamine and noradrenaline.1,7 The brain and the muscles are connected biochemically through feedback between the levels of free fatty acids and amino acids: when the body uses up its sugar energy stores, fats and proteins are then liberated for use as energy.8,9 The brain uses amino acids from the liberated proteins to make neurotransmitters, which in turn help regulate how we feel. The serotonergic system modulates mood, emotion, sleep and appetite, thereby controlling behavior and physiologic functions.8 Increases in the ratio of serotonin to dopamine cause feelings of lethargy and the loss of drive. This leads to a reduction of motor unit recruitment in the muscles in an effort to conserve energy until more glucose is ingested and/or introduced to the system. Fatigue is an integrated phenomenon, with interactions between central and peripheral factors.
Diagnosis Problems
Although OTS in athletes has been documented anecdotally for years by coaches, scientists have been hard-put to come up with repeatable tests that consistently identify chemical or physical changes in these athletes' bodies.10 A number of the experiments conducted used small study groups and did not induce a state of true "overtraining" because the athletes were forced to increase intensity over a short period of time to fall within the time boundaries of the experiment (12 weeks, for example).11 The work with biomarkers for oxidative stress, biochemical alterations in metabolic processes and endocrine dysfunction all show much promise in explaining how and why overtraining causes fatigue and underperformance. 1,9,11 But more questions, than answers, have been raised, many of which have to do with conducting well-controlled experiments on larger samples of athletes.
Practical Applications
While it isn't necessary to hold a degree in biochemistry or neuroscience to train athletes safely, a basic understanding of possible causes for OTS may help in formulating a plan when an athlete does begin to complain of feeling burned out and weak, even after months of diligent training. There may not be a hallmark set of clinical markers yet that can be tested in the blood to make the specific diagnosis of OTS, but by excluding other illnesses through a thorough history and physical examination, it's possible to make a pretty good educated guess if an individual is suffering from OTS.
The athlete's diet must be examined for caloric intake, specifically in the form of carbohydrates. Anyone ingesting too few calories and not enough readily available calories in the form of complex carbs will exhibit signs of fatigue and weakness and even mood disturbances. Blood tests for anemia, hypothyroidism, Lyme disease and other infections may show organic causes of fatigue and weakness.1
In light of the myriad of influences on health, it is prudent to analyze how often an athlete is eating, what his/her sources of nutrients are and whether s/he is giving himself adequate rest periods between bouts of exercise. The best way is to start with a log.5,10
Keep a training log with notes on both subjective and objective findings. It is common sense to record weight, speed, types of exercises, number of reps, heart rate and dietary intake, but also have the athlete take notes on feelings after each workout, rates of perceived exertion and enthusiasm or tiredness. If the pace slows, a resting heart rate increases or there are consistent complaints of fatigue, the athlete may be overtraining. Before starting any extreme conditioning program, sport-specific exercise testing conducted to exhaustion provides a baseline against which future performance can be judged.4 Although this requires discipline, planning and long-term commitment to the athlete, personal trainers and coaches who keep good, accurate records may save themselves from losing a full season of competition from valuable, talented athletes.
Treatment
Avoid OTS by using cyclical training and periodization.1,5 Alternate hard, easy and moderate periods of training. This should give the body enough time to recuperate from very strenuous training sessions: tissues need time to heal. Also, encourage good sleep habits. Most healing occurs during sleep. Sleep is important for brain function, too.
Keep boredom from occurring with cross training.1 While a variety of exercises will ensure that the same joints and muscles aren't being used over and over, it also forces the athlete to think differently.
When the athlete does present injuries or soreness, rest and physical therapy, including massage, are recommended. Depending on the severity of the injuries, rest can be "active," if the exercise avoids using the injured body parts, just to keep the athlete psychologically in the game.1,5,12
To help facilitate recovery of energy and healing of tissues, nutritional intake must be adjusted with the guidance of a licensed nutritionist or physician who may recommend vitamins and minerals, such as B vitamins, calcium, potassium, magnesium and vitamin C, depending on the acuteness of the symptoms and injuries.
The hydration status of the athlete must also be taken into consideration, not only acutely during exercise, but when recovering during the rest period. Dehydration has been shown to decrease one¿repetition maximum performance and anaerobic power in the upper and lower extremities, and it reduces aerobic endurance. 13,14,15 Adequate fluid ingestion favorably influences athletic performance by maintaining stroke volume, cardiac output, serum osmolality and sodium concentration.16 However, there has been no connection proven between hydration and muscle cramps or soreness.17,18
Conclusion
Inconsistent changes have been documented in the areas of physiologic functioning, impairments in psychological processing, immunologic dysfunction and biochemical abnormalities in the diagnosis of OTS. Although the cause or etiology of this failure to perform remains difficult to pinpoint, studies and experiments examining the neuro-endocrine-immune dysregulation resulting in the stress-related disorder, OTS, have only just begun to scratch the surface.6
Jodai Saremi, DPM, is AFAA certified in group exercise and personal training. She is a contributing editor for American Fitness and enjoys writing about a variety of health and fitnessrelated subjects.
REFERENCES:
Armstrong, L.E. and VanHeest, J.L. "The Unknown Mechanism of the Overtraining Syndrome. Clues from Depression and Psychoneuroimmunology." Sports Medicine, 32, No. 3 (2002): 185-209.
Urhausen, A. and Kindermann, W. "Diagnosis of Overtraining: What Tools Do We Have ?" Sports Medicine, 32, No. 2 (2002): 95-102.
Budgett, R., et al. "Redefining the Overtraining Syndrome as the Unexplained Underperformance Syndrome." British Journal of Sports Medicine, 34, No. 1 (2000): 67-68.
Cosca, D.D. and Nava zio, F. "Common Problems in Endurance Athletes." American Family Physician, 76, No. 2 (July 2007): 237-44.
Yoke , M. Personal Fitness Training Theory and Practice. Sherman Oaks, Calif.: Aerobics and Fitness Association of America, 2006.
Angeli, A., et al. "The Overtraining Syndrome in Athletes: A Stress-Relate d Disorder." Journal of Endocrinological Investigation, 27, No. 6 (June 2004): 603-12.
Meeuse n, R., et al. "Central Fatigue : The Serotonin Hypothesis and Beyond." Sports Medicine, 36, No. 10 (2006): 881-909.
Meeuse n, R., et al. "Brain Neurotransmitters in Fatigue and Overtraining." Applied Physiology, Nutrition and Metabolism, 32, No. 5 (October 2007): 857-64.
Petibois, C., et al. "Biochemical Aspects of Overtraining in Endurance Sports: The Metabolis mAlteration Process Syndrome." Sports Medicine, 33, No. 2 (2003): 83-94.
Halson, S.L. and Jeukendrup, A.E. "Does Overtraining Exist? An Analysis of Overreaching and Overtraining Research." Sports Medicine, 34, No. 14 (2004): 967-81.
Ma rgonis, K., et al. "Oxidative Stress Biomarkers Responses to Physical Overtraining: Implications for Diagnosis." Free Radical Biology and Medicine, 43, No. 6 (September 2007): 901-10.
Peluso, M.A. and Guerra de Andrade, L.H. "Physical Activity and Mental Health : The Association Between Exercise and Mood." Clinics, 60, No. 1 (February 2005): 61-70.
Schoffstall , J.E., et al. "Effects of Dehydration and Rehydratio n on the One-Repetition Maximum Bench Press of Weight-Trained Males." Journal of Strength Conditioning Research, 15, No. 1 (February 2001): 102-08.
Jones, L.C., et al. "Active Dehydration Impairs Upper and Lower Body Anaerobic Muscular Power." Journal of Strength Conditioning Research, 22, No. 2 (March 2008): 455-63.
Barr, S.I. "Effects of Dehydratio n on Exercise Performance." Canadian Journal of Applied Physiology, 24, No. 2 (April 1999): 164-72.
Noakes , T.D. "Fluid Replacement During Exercise." Exercise & Sports Sciences Reviews, 21 (1993): 297-330.
Schwellnus, M.P., Derman, E.W. and Noakes, T.D. "Aetiology of Skeletal Muscle `Cramps' During Exercise: A Novel Hypothesis." Journal of Sports Science, 15, No. 3 (June 1997): 277-85.
Schwellnus, M.P., et al. "Serum Electrolyte Concentrations and Hydratio n Status are not Associated with Exercise Associate d Muscle Cramping in Distance Runners." British Journal of Sports Medicine, 38, No. 4 (August 2004): 488-92.
© 1995-2008 Aerobics and Fitness Association of America
AFAA Certification Testing Accredited by Vital Research.
Fitness Triage®, TeleFitness®, Nutrition Gets Personal™,
Exercise Gets Personal™ and Fitness Gets Personal®
are protected by U.S. patent.
15250 Ventura Blvd., Suite 200, Sherman Oaks, CA 91403.
1-877-YOUR-BODY (1-877-968-7263)
Mon-Fri 6:30am-6:30pm Sat 7am-1pm PST