8 - Performance & Recovery

Vocabulary flashcards covering rest-to-exercise transitions, oxygen deficit, EPOC, lactate threshold, and metabolic fuel selection based on lecture notes.

Resting Oxygen Consumption (Absolute)

The volume of oxygen consumed at rest, measured as approximately $0.25\,L/min$.

Resting Oxygen Consumption (Relative)

The volume of oxygen consumed at rest relative to body mass, measured as $3.5\,mL/kg/min$.

Oxygen Deficit ($O_2$ Def.)

The lag in oxygen uptake at the beginning of exercise before reaching a steady state.

Steady State

The point reached within $1-4$ minutes of exercise where the ATP requirement is met through aerobic ATP production.

Oxygen Debt

The repayment for the oxygen deficit at the onset of exercise, characterized by oxygen uptake remaining elevated above resting levels during recovery.

Excess Post-exercise Oxygen Consumption (EPOC)

A term used interchangeably with oxygen debt, reflecting that only approximately $20\%$ of elevated oxygen consumption is used to repay the oxygen deficit.

Rapid Portion of EPOC

The initial recovery phase focused on the resynthesis of stored PC (phosphocreatine) and replenishing muscle and blood $O_2$ stores.

Slow Portion of EPOC

The recovery phase involving increased heart rate, breathing, body temperature, hormone levels, and the conversion of lactic acid to glucose.

Lactic Acid Oxidation

The process by which $70\%$ of lactic acid is removed following exercise, according to recent evidence.

Upward Drift in Oxygen Uptake

The increase in oxygen uptake over time during prolonged exercise in a hot/humid environment, caused by rising body temperature and epinephrine/norepinephrine levels.

$$VO_2\,\text{max}$$

The "physiological ceiling" for the delivery of oxygen to the muscle, where oxygen uptake no longer increases despite an increasing work rate.

Lactate Threshold (LT)

The point during incremental exercise at which blood lactic acid rises systematically (approximately $50-60\%$ $VO_2\,\text{max}$ for untrained subjects).

Onset of Blood Lactate Accumulation (OBLA)

The specific exercise intensity at which blood lactate levels reach $4\,mmol/L$.

Delayed Onset Muscle Soreness (DOMS)

Muscle soreness occuring $24-48$ hours after exercise caused by microscopic injury to muscle fibres and inflammation.

Respiratory Exchange Ratio (RER)

The ratio of carbon dioxide produced to oxygen consumed ($VCO_2/VO_2$), used to estimate the percentage of fat or carbohydrate utilization.

Crossover Concept

The shift from fat metabolism to carbohydrate metabolism as exercise intensity increases.

$$FAT_{max}$$

The highest rate of fat oxidation, which is reached just before the lactate threshold.

Lipolysis

The breakdown of triglycerides into glycerol and free fatty acids, stimulated by rising blood levels of epinephrine.

Muscle Glycogen

The primary source of carbohydrate during high-intensity exercise and the first hour of physical activity.

Plasma Free Fatty Acids (FFA)

The primary source of fat during low-intensity exercise, sourced from adipose tissue lipolysis.

Cori Cycle

The cycle in which lactate is converted to glucose in the liver and transported back to the muscle as fuel.