Key Concepts in Exercise Physiology and Training Adaptations

What happens to VO2 at the start of constant-load exercise?

Rapidly increases, reaches steady state in 1-4 minutes.

Is resting VO2 zero? Why or why not?

No — the body always uses oxygen for basic metabolic processes.

What is oxygen deficit?

The difference between O2 needed and O2 consumed at exercise onset.

What is EPOC?

Excess Post-exercise Oxygen Consumption — extra oxygen needed after exercise.

What is VO2max?

The maximum rate of oxygen uptake, transport, and utilization during exercise.

What is the Fick equation for VO2max?

VO2max = Cardiac Output × a-vO2 difference.

What are the three muscle fiber types?

Type I (slow twitch), Type IIa (fast oxidative glycolytic), Type IIx (fast glycolytic).

Which fiber type is fatigue-resistant and has high mitochondria?

Type I (slow twitch).

Which muscle fiber type fatigues quickly but produces high force?

Type IIx (fast glycolytic).

What is the size principle of recruitment?

Low-threshold fibers (Type I) recruited first, then higher-threshold (Type II) as intensity increases.

Why are carbohydrates important during heavy training?

Restore muscle glycogen and delay fatigue.

What is carbohydrate loading?

Increasing carb intake before an endurance event to maximize glycogen stores.

How much can athletes sweat per hour?

1-2.5 liters.

What is the RDA for protein?

0.8 g/kg/day (1.2-2.0 g/kg/day for active people).

What factors influence muscle protein balance?

Protein intake and resistance training.

What happens with sprint/strength training?

Increases anaerobic enzymes and PCr/glycogen stores.

What are endurance training adaptations?

Increases mitochondria, capillaries, oxidative enzymes, and delays lactate threshold.

What happens to VO2max and cardiac output with training?

Both increase.

What causes early strength gains?

Neural adaptations.

What is muscle hypertrophy?

Increase in muscle fiber size.

What is the principle of specificity?

Adaptations specific to the muscles and systems trained.

What is progressive overload?

Increasing stress to cause adaptations.

What is reversibility?

Loss of gains when training stops.

What is periodization?

Systematic training variation to peak at desired times.

How can overtraining be prevented?

Manage workload, recovery, and nutrition.

What are ACSM exercise guidelines for adults?

150 min moderate or 75 min vigorous aerobic exercise/week + strength + flexibility.

What's the difference between strength, endurance, and power?

Strength: Max force, Endurance: Sustained contractions, Power: Force × velocity.

What is DOMS?

Delayed Onset Muscle Soreness from eccentric muscle damage.

How does VO2max change with age?

Decreases ~1% per year after 25-30.

What contributes to strength loss with aging?

Muscle atrophy and fewer fast-twitch fibers.

How does physical activity affect mortality?

Lowers risk of all-cause death.

What did the Harvard Alumni Study find?

More activity = lower risk of CVD, cancer, and death.

What did the Cooper Clinic data show?

Fitter individuals have lower cancer and heart disease risk.

What is the dose-response relationship for exercise?

More activity = greater benefits up to a point.