Week 06 Flashcards
What is fatigue?
- Common sensation
- Can be intense enough so that reduce workload or cease exercise
- All physical exercise if continued long enough will lead to fatigue
- All physical activity alters internal environment
- negative effects on physical health or even survival
Defining fatigue?
- Lack of consistent meanings
– Over reaching (short term)
– Over training (long term)
– Staleness
– Fatigue , physical fatigue, Chronic fatigue, persistent fatigue, over fatigue
– Emotional exhaustion, burnout
– Overuse
– Overwork
Is fatigue always bad??
Stimulus Compensation Adaptation Cycle or General Adaptation Syndrome (GAS) Theory
- Before exercise everyone has original performance capability level
- Stimulus creates fatigue, shown by decrease in individuals performance capacity
- After exercise: performance increases back to same level during recovery (resistance/adaptation phase)
- Performance ability begins to exceed original performance level (if correct exercise dose), new level of ability/performance = adaptation
- BUT, if exercise stimulus is TOO HIGH, instead of performance increase post exercise, it will continue to decline
Progressive overload: suboptimal vs optimal load
- Suboptimal training stimulus (no overload) = won’t get supercompensation –> won’t get adaptation –> won’t get improvement in performance
- Optimal training stimulus (overload) = will get supercompensation –> will get adaptation –> improved performance abilities
Intensity, progression, timing are crucial
- Timing training sessions to peak of supercompensation of previous session is crucial
- Continue to progress stimulus to continue to improve performance ability
- Overtraining if next session is before supercompensation.
- Need to get intensity AND timing correct
Cause of fatigue depends on…
- exercise
- subject
- environment
Fatigue is the moment…
when subject is unable to maintain the required muscle contraction or workload
Physiological fatigue vs psychological fatigue…
- Physiological fatigue
- including biochemical
- objective markers - Psychological fatigue
- subjective
- sense of effort increasing
- difficult to measure/monitor
Central fatigue vs Peripheral fatigue…
- Central fatigue
- extra-muscular
- independent of intramuscular and/or metabolic factors
- related to motor neuron discharge - Peripheral fatigue
- within muscle
- biochemical physiological
Peripheral fatigue
Areas fatigue could be originating:
- changes in electrical properties of sarcolemma, SPR and T-tubules
- Excitation coupling
- Cross bridge function
- Bioenergetic processes
Fatigue Prevention/Amelioration - we want RIGHT amount of fatigue, which relies on:
- Training status
- Nutrition
- recovery strategies
Two types of muscle soreness that are fatigue related:
- Acute Muscle soreness
- During or immediately upon finishing intense exercise
- NOT injury related
- Disappears mins to hour post exercise
- Delayed onset muscle soreness (DOMS)
- delayed
- lasts 24-48 hours
Acute muscle soreness
- Very short term
- Accumulation of metabolites H+
- Irritation of nerve endings
- Tissue oedema
- Caused by the shifting of fluid into the muscle from the blood
- increased BP
- Changes in capillary permeability
- Caused by the shifting of fluid into the muscle from the blood
- Accumulation of metabolites H+
- Prevention and Amelioration
- As for fatigue
DOMS
- Followed unaccustomed exercise
- Large volume
- High intensity
- Eccentric
- Muscular soreness
- stiffness
- localised tenderness
- pain that interferes with movement
- Appears - 24hrs post exercise
- Peaks at 48 hrs post exercise
- Self limiting/recovering
DOMS Mechanisms?
A number of theories:
- Lactate H+ accumulation theory – Debunked!
- Torn tissue? – Some evidence
- Tonic muscle spasms – some evidence
- Connective tissue damage: some evidence
- Structural damage from high tension – Some evidence
- Acute inflammation – some evidence
- Muscle, CT damage triggers an increase in circulating neutrophils
- Neutrophils travel down damaged site, followed by monocytes
- monocytes produce large amounts of prostaglandins
- Prostaglandins sensitise the afferent nerve endings in muscles, leading to sensation of muscle soreness
- This all can be related to muscle temperature
Consequences of lack of specificity
- Muscle soreness in recovery
- acute localised muscle fatigue
- subjectivity athlete perceives the work as harder than usual
- more rapid onset of fatigue
- lower cross over of gains to sports performance
Specificity of Adaptation
- Stressor MUST exceed current levels of ‘comfortable tolerance’
- Adaptation
- Performance improvements
- Too little
- plateau
- Too much
- Maladaptation
- Overtraining
- injury
- decrease performance
- Maladaptation
General adaptation syndrome theory
- If you get it right –> maximum level of adaptation, no involution
- If you get it partially right –> some adaptation
- If you get it wrong –> overtraining, exhaustion, no adaptation
No overload =
no supercompensation. = no performance improvement
No varying training stimulus between sessions =
quickly reach plateau in performance –> need to continue to progress
Timing =
time next training session at peak of previous session’s supercompensation for ideal performance improvement
For progressive overload, Stressor must exceed current levels of ‘comfortable tolerance’ AND there must be ….
- repeated exposure
- progressive increase
Factors influencing rate of progression:
- Individual ability to handle stress
- type of activity affects rate of response
- simple produce
changes quickly
- simple produce
- Genetic limit to fitness component development
- Once reached further
attempts to increase
are of little value and
may be harmful
- Once reached further
General Guidelines: Progressive Overload
- Aim to develop only to a level that can be fully used in the sport
- Work within the athletes threshold capacity
- not too easy or too hard
- Different components develop at different rates
- Segment volume and segment intensity
- Increase one decrease the other
- cyclical training stress
- be aware of non training sources of stress
