What is positive stress?
Positive stress: training that causes
improvements in exercise performance
– Major training adaptations in 6 to 10 weeks
– Depends on volume and intensity of training
– Quantity training versus quality training
How is the rate of adaptation genetically limited?
– Too much versus just right varies
– Too much training - decrease performance and increase injury
What does overtraining result in?
• Overtraining - performance decrements
– Chronic fatigue, illness
– Overuse injury, overtraining syndrome
Why is progressive overload important?
– Progressively stimulus as body continually adapts
– Stimulates continuous improvements
What does undertraining result in?
– Adaptations not fully realized
– Optimal performance not achieved
What is overreaching?
• Systematic attempt in overstressing body
for short period of training
– Allows body to adapt to stronger stimulus
– Not same as excessive training
– Caution: easy to cross into overtraining
• Short performance decrement followed by
improved performance and function
What does excessive training result in?
• Volume and/or intensity to an extreme
– For years, many athletes undertrained
– As intensity/volume , so did performance
– More is better is not true after a point
• Can lead to strength, sprint performance
Is high-volume training beneficial? Why?
• Value of high-volume training questionable
– In some sports, half the volume may maintain
benefits and decrease risk
– Low intensity, high volume inappropriate for sprinttype performance
What is meant by intensity and volume being inversely related?
– If volume increases, intensity should decrease
– If intensity increases, volume should decrease
– Different emphasis - different fitness results
– Applies to resistance, anaerobic, and aerobic
training
• increased Intensity + increased volume = negative effects
What is periodization of training?
• Traditional periodization programs divide into
cycles that range from multi-year to micro-cycles
that last a few days
• Best for athletes who focus on one competition
• Not optimal for team sports or sports that require
skill development
• Block periodization gaining popularity as it allows
focus on a few skills/attributes, 3-4 blocks that last
2-4 weeks
Can overtraining be remedied?
– Cannot be remedied by short-term training, rest
– Putative psychological and physiological causes
– Can occur with all forms of training: resistance,
anaerobic, aerobic
What are the symptoms of overtraining syndrome?
– decreased Strength, coordination, capacity
– Fatigue
– Change in appetite, weight loss
– Sleep and mood disturbances
– Lack of motivation, vigour, and/or concentration
– Depression
• Psychological factors
– Emotional pressure of competition = stress
– Parallels with clinical depression
• Physiological factors
– Autonomic, endocrine, and immune factors
– Not a clear cause-and-effect relationship but
significant parallels
What is the sympathetic NS response to overtraining syndrome?
- Increased BP
- Loss of appetite
- Weight loss
- Sleep and emotional disturbances
- Increased basal metabolic rate
What is the parasympathetic NS response to overtraining syndrome?
- Early fatigue
- Decreased resting HR
- Decreased resting BP
- Rapid heart rate recovery
- More common with endurance athletes
What are the endocrine responses to overtraining syndrome?
• Resting thyroxine, testosterone decreased
• Resting cortisol increased
• Testosterone:cortisol ratio
– Indicator of anabolic recovery processes
– Altered ratio may indicate protein catabolism
– Possible cause of overtraining syndrome
• Volume-related overtraining appears more
likely to affect hormones
• increased Blood urea concentration
• Resting catecholamines increase
• Outside factors may influence values
– Overreaching may produce same trends
– Time between last training bout and resting blood
sample critical
– Blood markers helpful but not definitive diagnostic
tools
What are the neural and endocrine factors of overtraining syndrome?
• Overtraining stressors may act primarily
through hypothalamic signals
– Can lead to sympathetic neural activation
– Can lead to pituitary endocrine cascade
• Hormonal axes involved
– Sympathetic-adrenal medullary (SAM) axis
– Hypothalamic-pituitary-adrenocortical (HPA) axis
What are immune responses to overtraining syndrome?
• Circulating cytokines
– Mediate inflammatory response to infection and
injury
– increase In response to muscle, bone, joint trauma
– increased Physical stress + decreased rest = systemic inflammation
• Inflammation - increased cytokines via monocytes
• May act on brain and body functions,
contribute to overtraining symptoms
• Compromised immune function factor in
onset of overtraining syndrome
• Overtraining suppresses immune function
– Abnormally decreased lymphocytes, antibodies
– increased Incidence of illness after exhaustive exercise
– Exercise during illness - immune complications
How can we predict overtraining syndrome?
• Causes unknown, diagnostics difficult • Threshold different for each athlete • Most coaches and trainers use (unreliable) intuition • No preliminary warning symptoms – Coaches do not realize until too late – Recovery takes days/weeks/months of rest • Biological markers have limited effectiveness
What are some treatment and prevention methods that can be utilised for overtraining syndrome?
• Treatment
– Reduced intensity or rest (weeks, months)
– Counseling to deal with stress
• Prevention
– Periodization training
– Adequate caloric (especially carbohydrate) intake
What is tapering?
• Tapering = reduction in training
volume/intensity
– Prior to major competition (recovery, healing)
– 4 to 28 days (or longer)
– Most appropriate for infrequent competition
What does tapering result in?
• Results in increased muscular strength
– May be associated with contractile mechanisms
– Muscles repair, glycogen reserves replenished
• Does not result in deconditioning
– Considerable training to reach V•
O2max
– Can reduce training by 60% and maintain V•
O2max
• Leads to improved performance
– 3% improved race time
– 18 to 25% improved arm strength, power
– Effects unknown on team sports, marathons
What is detraining?
• Loss of training-induced adaptations – Can be partial or complete – Due to training reduction or cessation – Much more substantial change than tapering • Brief period = tapering • Longer period = detraining • Immobilization – Immediate loss of muscle mass, strength, power • Training cessation – Rate of strength and power loss varies
What does detraining cause?
– Atrophy (immobilization)
– Reduced ability to recruit muscle fibers
– Altered rates of protein synthesis versus degradation
• Muscle endurance quickly
– Change seen after 2 weeks of inactivity
– Not clear whether the result of muscle or
cardiovascular changes
• Oxidative enzyme activity decreases by 40 to 60%
• Muscle glycogen stores decrease by 40%
• Significant acid–base imbalance; exercise
test once weekly during detraining showed
– Blood lactate accumulation increases
– Bicarbonate decreases
– pH decreases
What are some cardiorespiratory losses as a result of detraining?
– Significant increase in submaximal HR
– 25% decrease submaximal stroke volume (due to plasma
volume)
– 25% decrease maximal cardiac output
– 27% decrease V•O2max
• Trained athletes lose V•O2max faster with
detraining, regain it slower
