3.1.1.6 Energy Systems

ATP (Adenosine Triphosphate)

The only useable form of energy in the body, broken down into ADP + PI

What does ADP-PI release energy for

Muscle contraction, active transport, heat production

Why must ATP stores be continuously resynthesized

As the stores are limited an the body never uses just one, its an energy continium

Aerobic energy system functions

Longer duration, lower intensity exercise by resynthesizing slower

Order of aerobic energy system

Glycolysis, Krebs cycle, Electron transport chain, Beta oxidation

glycolysis in the aerobic energy system

Anaerobic process in the sarcoplasm where glucose is converted to pyruvate to produce energy

Krebs cycle in the aerobic energy system

Chemical reactions in the mitochondria convert pyruvate to Acetyl CoA

What is produced as well as Acetyl CoA in the Krebs cycle

C02, hydrogen and small ATP yield

Electron transport chain in aerobic system

Hydrogen from the Krebs cycle is oxidised to water and a large 34 ATP production

Beta oxidation in aerobic energy system

Fatty acids also broken down into Acetyl CoA for a large ATP yield, requires oxygen and is slow

Advantages of aerobic energy system

High ATP yield, Sustainable, No fatiguing by products

Negatives of aerobic energy systems

Slow ATP resynthesis, Requires oxygen

ATP - PC system

Uses energy rich phosphocreatine for explosive and short duration movements

Stage 1 of the ATP - PC system

Phosphocreatine broken down by creatine kinase to release phosphate, creatine and energy

Stage 2 of the ATP - PC system

Energy from phosphocrteatine used to convert ADP into ATP in a coupled reaction

Stage 3 of ATP - PC system

PC is resynthesized aerobically every 2-3 minutes

Advantages of ATP - PC system

Fastest ATP production, no fatiguing by products

Disadvantages of ATP - PC system

Very limited PC stores, Lasts only 8-10 secs

Anaerobic glycolytic system purpose and features

High intensity exercise lasting 10 secs - 2 mins

Process of anaerobic glycolytic system

Glycogen into glucose into pyruvate (no oxygen) creates lactate and a 2 ATP gain

Lactate threshold

Lactate production exceed removal

What is the effect of reaching the lactate threshold

increasing the presence of hydrogen and causing fatigue through lower PH (OBLA)

Lactate producing capacity

The potential of the body to generate ATP and the by product lactate

Advantages of Anaerobic Glycolytic system

Rapid resynthesis with o2, High intensity with limited o2

Disadvantages of anaerobic glycolytic system

Low ATP yield, Fatigue due to hydrogen accumulation

Lactate Tollerance

Ability of the body to buffer the hydrogen ions and lactate

Fast Twitch (Type II) muscles features

High PC stores, High glycogen stores, High level of ATPase through anaerobic systems

Slow Twitch (Type I) muscles features

High mitochondria density, aerobic system, High myoglobin content

Short duration energy transfer during exercise features

Rapid ATP resynthesis, High lactate accumulation, Oxygen defecit

Long duration energy transfer during exercise features

Aerobic system, steady oxygen supply, fats/carbs used, minimal lactate accumulation

O2 consumption

The amount of oxygen to produce ATP

Sub maximal O2 defecit

Not enough O2 available to start to provide as the oxygen supply and mitochondria activity lags behind the demand so anaerobic systems compensate

EPOC

Amount of oxygen during recovery to return body to resting state. Removes lactate (converted to glycogen in liver) and resynthesises ATP-PC

Fast component of recovery

Restoration of ATP and phosphocreatine stores with oxygen

Slow component of recovery

Longer lasting and uses O2 to remove lactic acid

Factors affecting lactate accumulation

Exercise intensity, trained performers, muscle fibre type

How does exercise intensity effect lactate accumulation

Greater reliance on anaerobic glycolysis means lactate is accumulated

How does being a trained performer effect lactate accumulation

Higher threshold and better lactate removal

How does muscle fibre type effect lactate accumulation

Fast twitch are anaerobic and produce lactate faster

Factors affecting VO2

Genetics, Age, Gender (20%), Lifestyle, Training, Body composition

Measurements of energy expenditure

Indirect calorimetry, lactate sampling, vo2 max

Indirect calorimetry

Measures oxygen uptake and estimates energy expenditure

Lactate sampling

Blood sample from finger identifies threshold and measures lactate concentration

Vo2 max test

Incremental treadmill test that measures max O2 uptake

Training methods on energy systems

Altitude training, HIIT, Plyometrics, Speed/Agility/Quickness

Speed Agility and Quickness

Aims to impact energy systems through coordinated multi directional movements

Altitude training

Training at over 200m above sea level for at least 30 days. Stages of acclimatisation, primary training and recovery

HIIT

Training method that alternates between short bursts of high-intensity exercise and periods of rest or lower-intensity exercise. Primarily develops ATP-PC but also develops aerobic

Plyometrics

Eccentric muscle contractions followed immediately by contraction to improve ATP-PC system during bounding/jumping. Develops explosive strength

Altitude training evaluation

Boosts aerobic power/VO2 max by producing EPO to increase RBC count, Increased oxygen carrying ability from haemoglobin concentration delays OBLA, Increased myoglobin allows more oxygen to be transported to mitochondria. Altitude sickness, Benefits lost within days, Very expensive/time consuming, Psychological effects like home sickness reduce training effectiveness

HIIT training evalutation

Mirrors the demands of sport specific skills with anaerobic and aerobic systems, Improves anaerobic power and in times of fatigue, Improves a range of components of fitness (muscular endurance, speed). High risk of injury, Intensity negatively impacts skill training and tactic development, not appropriate for all positions.

Plyometrics evaluation

Improves PC resynthesis for ATP-PC movement, Increases power by neuromuscular efficiency, Replicate explosive in game movements. Injury risk, longer recovery period so sessions have to be planned to avoid fatigue, difficult to develop tactics

Speed/agility/quickness evaluation

Improves speed of muscle recruitment/response time through motor abilities, Can be applied to sporting scenarios. Lack of mental training/decision making, limited aerobic development, injury risk