Optimal Training - Extreme physiology

1. Volume of training

Advantages with optimal volume of training

If max amount of volume possible was optimal, those who did most would be most successful - this is not the case

Average training expenditure should be about 20-25,000kJ/week

Degree of adaption depends of intensity

Specific to speed and duration of activity during training

Those who wish to perform high intensity need to train at high intensity - low intensity does not adapt neuromuscular pathways necessary

Interval training - effective way of training at high intensity

Hydrolysis of ATP provides energy for muscle contractions

Muscle relaxation and nerves also require ATP

Mechanisms:

ATP stores

PCr stores 

Oxidative phosphorylation

Phosphocreatine <--> Creatine

Catalysed by creatine kinase

Reversible reaction

Provides energy during brief intense bursts

Enough ATP generated for about 10-20s

Stores are rapidly resynthesised following exercise

Activities sustained for more than 20s have ATP demands exceeding max that can be supplied by ATP/PCr stores

Therefore ATP production needs to be anaerobic

Pyruvic acid from glycolysis (which generated 2 ATP per reaction) is converted to lactic acid

This means that NADH can be reused in glycolysis so the reaction can keep happening to keep generating ATP

However the lactic acid has uncomfortable effects - fatigue and decreased pH

During sustained moderate exercise

1. Aerobic glycosis

2. Acetyl Co-A

3. TCA cycle

4. Oxidative phosphorylation

High yeild of ATP and sustainable

1. Slow oxidative

Fatigue resistant, high mitochondrial content, myoglobin stores, low power, high endurance

2. Type IIX

Rapid, powerful contraction, fatigue quickly, low mitochondria, PCr stores

3. Type IIa 

Contract rapidly, high oxidative capacity, power output and fatigue resistance intermediate

High intensity:

Lactic acid generated as by-product of anaerobic glycolysis

Compression of vessels supplying blood to these fibres - decreases O2 delivery and lacate removal

pH falls

Low intensity:

Oxidative fibres recruited - no lactate accumulation

Substrate depletion is more likely to occur

Adaption is specific to muscles trained, intensity and metabolic demands

High degree of carryover to sport concerned is necessary

Need similar demand on neuromuscular coordination of movement

Muscle or physiological component needs to be exerted at a level at which it is not usually acustomed to

Muscle needs to be stimulated with resistance of relatively high intensity

During a training program - adaptions occur that alter relative intensity or volume

To maintain same training stimulus the load needs to continuously be modified

To maximise further strength gains the resistance needs to be increased

People respond differently to different programs/training stimulus

Could be influenced by:

1. Pre-training status

2. Genetic predisposition

3. Gender

4. Age

Must be adapted to suit individual

Gains are related to experience of individual

Novices tend to experienc large gains to begin with, that slowly disapear with experience

As training continues, a plateau appears to be reached

When training stimulus is removed, the ability of an athlete to maintain performance is also reduced

Gains made will eventually be completely lost and athlete will return to untrained state

Decreases in aerobic capcity (4-6% reduction in VO2max) have been noted after 2 weeks of inactivity

Also occurs in strength and power

Changes in muscular strength and cardiorespiratory endurance detrain more rapidly than changes in anaerobic forms of activity

Increase in cross sectional fibre size

Sprint and resistance training has been shown to induce change in fibre type from type I to type II

Even in absence of conversion - selective hypertrophy of type II leads to increase in fraction of type II compared to type I fibres

Maximal efforts lasting 6s place highest demands on ATP-PCr system so reasonable to assume that these bouts would induce adaption

However study found that 30s bout actually increase activity of 2 key enzymes in ATP-PCr system

30s bouts increases activity of several key glycotic enzymes

Glycogen phosphorylase, phosphofructokinase and lactate dehydrogenase all increased by 10-25% following repeated bouts of maximal exercise

Training at high speeds improves skill and coordination when performing at higher intensities

Neuromuscular adaptions sprint training are assumed to optimise fibre recruitment to allow more efficient movement

Using heavy loads as well - results in more economical use of muscle's energy

Anaerobic training increases muscle's capacity to tolerate the H+ that accumulates within them due to the lactic acid production

Effect is primarily due to increases in muscle buffer capacity - can be increased by up to 40-50% following 2 months of anaerobic training

Major intracellular buffers in muscle are phosphates, histidine-containing peptides and proteins

Extracellular buffering is also enhanced - beneficial because it allows H+ to leave to muscle fibre at faster rate

Bicarbonate and blood proteins e.g. albumin and haemoglobin are important buffers