Energy Transfer In Exercise

Immediate Energy

• ATP-PCr System

• 5-8 sec of max intensity exercise

• Sprinting, football, weight lifting baseball, volleyball, etc.

Short-Term Energy

• Lactic Acid System (Anaerobic glycolysis)

• Maximal exercise between 60-180 seconds

• Increases blood lactate

• Lactate ranges from .5 – 20 mmole.L-1

• Half-life is ~ 15-30 min

• Removal is fasted during low-moderate aerobic exercise

Lactate Accumulation

• Onset of Blood Lactate Accumulation (OBLA)

• Blood Lactate Threshold

• Anaerobic Threshold

Trained vs Untrained

• Genetic endowment– Muscle fiber type– Blood flow characteristics

• Local training adaptations– Less lactate production– Greater lactate production– Greater lactate removal

Long-Term Energy

• Oxygen consumption , oxygen uptake

• VO2

• Resting values

• Submaximal values

• Maximal values

Units for VO2

• Absolute Units– ml.min-1

– L.min-1

• Relative Units– ml.kg-1.min-1

Reasonable VO2 Values

ml.kg-1.min-1 ml.min-1 METS

Rest 3.5 200-300 1

Maximal 40-55 2500-4000 11.4-15.7

Elite 75-85 5000-60000 21.4-24.3

Where Does the O2 Go?

• Resynthesize ATP and PCr

• Resynthesize lactate to glycogen

• Oxidize lactate

• Restore O2 to myoglobin

• Increased HR and ventilation

• Increased catecholamines

• Elevated core temperature