Ch.2

Bioenergetics

Flow of energy in a biological system; conversion of macronutrients into energy

Bodily energy

Ability to do work

Mechanical work

Muscular contraction

Catabolism

Breakdown of large molecules into smaller ones; release of energy

Anabolism

Synthesis of small molecules into larger ones

Exergonic

Energy-releasing reactions that are generally catabolic

Endergonic

Require energy and include anabolic processes (contraction)

Metabolism

Total of all the catabolic/exergonic and anabolic/endergonic reactions

Adenosine triphosphate ATP

Allows the transfer of energy from exergonic to endergonic

Phosphagen System

• In the sarcoplasm/cytoplasm

• Short-term, high-intensity

• Active at the start of ALL exercises

• Replenishes ATP rapidly

• Uses creatine kinase to maintain concentration of ATP

ATP Stores

• Body does not store enough ATP for exercise

• Needed for basic cell function

Glycolysis

• Breakdown of carbohydrates to resynthesize ATP

• Carbs can be broken down without the presence of O2

Enzymes

Protein that increases rates of chemical reactions; “lock and key”: substrate must match enzyme

Lactate

• Fast glycolysis

• ATP resynthesis occurs at a faster rate but limited in duration

• Small portion acts as energy substrate (gluconeogenesis)

Fatigue

• Accumulation of bad or depletion of good

• Primary cause: metabolic acidosis

• Hydrogen ion accumulation due to high concentrations of lactate; hypoxia environment

• Lactate is secondary cause of fatigue

Pyruvate

• Slow glycolysis

• ATP resynthesis rate is slower but longer duration

• Enters mitochondria and converted to Acetyl-CoA

Glycolysis from one molecule of blood glucose yields a net of ____ ATP

2

Glycolysis from muscle glycogen yields a nat of _____ ATP

3

Lactate Threshold

Exercise intensity which removal of blood lactate can no longer match production

• Elite athletes have a greater removal of LA

LT begins at _____ in untrained but at _____ in trained

50-60%; 70-80%

Onset of Blood Lactate (OBLA)

Second increase in the rate of lactate accumulation (occurs at higher relative intensities of exercise)

Oxidative (aerobic) system (Krebs)

Primary source of ATP at rest and during low-intensity activities

Metabolism of blood glucose and muscle glycogen begins with glycolysis and leads to the ______

Kreb’s cycle

Energy yield of oxidative w/ ETC for glucose is ____ and glycogen is ____

38 ATP; 39 ATP

Rate = ATP production

Speed

Capacity = ATP production ____

Duration

Phosphagen energy system

ATP for high-intensity/short duration

Glycolytic system

ATP for mod-high intensity/short-medium duration

Oxidative system

ATP for low-intensity/long duration

ATP primary production factor is

Intensity

ATP secondary production factor is

Duration

The use of appropriate exercise intensities and ____ intervals allows for the _____ of specific energy systems during training

Rest; selection

Metabolic specificity of training results in what 4 things:

1. Efficient/productive exercise regimens

2. Decrease risk of overtraining

3. Increase attention to training

4. Increased focus on SAID

Interval training uses predetermined _____ of exercise and ____ _____

Intervals; rest periods

Interval training

Repeated bouts (duty cycles) of high-intensity exercise with intermittent recovery periods

Benefit of interval training

More training can be done at higher intensities

Drawback of interval training

Hard to establish guidelines for choosing specific work to rest ratios

W:R ratio for Phosphagen

1:12 to 1:20 (5-10s)

W:R for fast glycolysis

1:3 to 1:5 (15-30s)

W:R for fast glycolysis and oxidative

1:3 to 1:4 (1-3min)

W:R for oxidative

1:1 to 1:3 (>3min)