Lecture 14 - Energy System Development (ESD)

Review:

• ATP-PC

• Glycolytic (anaerobic)

• Aerobic

• ATP fuels muscle contractions

• Dercise duration and intensity

All systems are active no matter the exercise

Putting the Conditioning before

• Cardiovascular: increased maximal cardiac output, increased stroke volume and reduced heart rate at rest

• Respiratory: more efficiency of synergistic muscle activation, better locomotion

• Muscular: increased aerobic capacity of the given musculature. Ultimately, allows trained athletes to perform work at a greater maximal oxygen uptake

• Bone and connective tissue: stimulation of bone growth, thicker cartilage at weight bearing joints

• Endocrine: increase in hormonal circulation and changes at the receptor level

The Phosphagen (ATP-PCr) System

• The phosphagen system provides energy (ATP) for short-term, high-intensity activities such as sprinting and power based exercises. It is also the first energy system activated at the start of all exercise

• Used to fuel intense, short term activities (fight or flight response)

• One step equation, fastest rate of energy production

• Phosphocreatine breakdown

The Glycolytic System

• Glycolysis is the breakdown of carbohydrates (glucose or muscle glycogen) to resynthesize ATP

• Supplies energy to the body via the breakdown of carbohydrate *glycolysis)

  • Fast (anaerobic glycolysis)

  • Slow (aerobic glycoluysis)

• Can be used as a primary energy system for exercise between 30s and 3 min, depending on the intensity

The Oxidative System

• The oxidative system is the dominant ATP source at rest and during long-duration, lower-intensity activity

• It primarily uses carbohydrates and fats, with proteins contributing under extreme or prolonged conditions

• Fat oxidation provides a much greater ATP capacity but at a slower rate

What Systmes are working when?

• Phosphagen System - provides immediate energy for very short, high intense efforts

• Glycolytic - provides short to medium energy for moderate to high-intensity effort

• Oxidative - provides long term energy for low0intensity, endurance activity

• Intensity dependent

  • Volume-intensity relationship

In reality - they all work together

Visual Representation of Systen in Use

Setting the Ceiling - VO2 Max

• Maximal aerobic power

  • Vo2max - the body ability to supply oxygen to the muscles

    • Gold standard, however not very accessible

  • Increase exercise duration = increase ATP demand

  • O2 consumption “cut-off” point

  • vo2max/aerobic endurance correlation

Lactate Threshold

• Point where blood lactate concentration surpases 1 mmol

• Better indicator of aerobic performance

• Related to max lactate steady state

• Trained vs untrained?

• Exercise economy

  • An improvement in movement economy can enhance maximal aerobic power (VO2max) and lactate threshold

  • E.g. endurance runner wih shorter stride length and faster stride frequency

Setting the Baseline

• Resting Heart Rate (RHR)

  • Measured in beats per minute (bpm)

  • Determined by genetics and fitness level

  • Indicator of aerobic fitness

  • Marker of overtraining

  • Can be elevated due to anxiety, dehydration, high ambient temperature, altitude, sickness, or digestion

Max Heart Rate

• Maximal heart rate

  • Primarily determined by genetics, age, and gender

  • Can vary up to 6-8 beats/min as a result of training

  • Must be assessed through fitness testing

  • (220-age = MHR) has a variability of 12  beats/min or more

  • MHR’s are different between running, cycling and swimming  for the same athlete

  • Fitness testing is the most accurate and effective method to determine HRmax

Threshold Heart Rates

• Aerobic Threshold Heart Rate

  • Definition: The HR at which anaerobic metabolism begins to increase

  • % of max HR: 60-65%

  • Blood lactate: 1-2mmol of lactate

  • RPE: 9-10

• Lactate Threshold Heart Rate

  • Definition: The HR at which lactate production exceeds lactate removal

  • % of max HR: 80-85%

  • Blood lactate: 4 mmol of lactate

  • RPE: 14

Zone-Based Conditioning

• Move from aerobic to anaerobic from zone 1 to 6

• Trying to increase performance

• W:R = work to rest ratio

• 1:2 = for evey one unit of work, you get two units of rest