Adaptations to Aerobic and Anaerobic Training

35 Question-and-Answer flashcards covering cardiovascular, respiratory, muscular, metabolic, and performance adaptations to aerobic, anaerobic, and HIIT training, as well as factors influencing individual responses.

What is muscular endurance?

The ability of a muscle or muscle group to sustain high-intensity, repetitive, or static contractions for an extended period, with fatigue specific to that muscle group.

Define cardiorespiratory endurance.

The cardiorespiratory system’s capacity to deliver oxygen to working muscles and the muscles’ ability to use that oxygen aerobically.

What physiological measure is considered the best indicator of cardiorespiratory endurance?

VO₂ max, the highest rate of oxygen consumption attainable during maximal exercise.

How much can VO₂ max typically increase in previously untrained individuals after ~20 weeks of endurance training?

About 15–20 %.

Why does submaximal endurance improve after aerobic training?

Because trained individuals achieve a lower steady-state heart rate at any given submaximal workload, reflecting improved efficiency.

State the Fick equation for oxygen consumption.

VO₂ = SV × HR × (a-v)O₂ difference.

Which component of the Fick equation shows little change with training, and which increases considerably?

HR_max stays the same (or decreases slightly), whereas (a-v)O₂ difference and stroke volume increase.

How does endurance training affect left-ventricular chamber size?

It increases chamber diameter and end-diastolic volume (preload), allowing greater filling and a larger stroke volume.

How does peripheral resistance change with endurance training, and what cardiac variable does this influence?

Peripheral resistance decreases, lowering afterload and thereby raising stroke volume.

What is training-induced bradycardia and its primary cause?

A lower resting heart rate due mainly to enhanced parasympathetic (vagal) tone and/or reduced sympathetic drive to the SA node.

Why is heart-rate recovery a useful fitness marker?

The faster HR returns to resting levels after exercise, the better the individual’s cardiorespiratory fitness and autonomic balance.

Does maximal heart rate (HR_max) change markedly with endurance training?

No, it remains essentially unchanged or may decrease slightly.

Why does maximal cardiac output (Q̇_max) increase after endurance training?

Because the trained heart can pump a larger stroke volume at maximal effort, raising overall cardiac output and supporting higher VO₂ max.

List four mechanisms that increase muscle blood flow during endurance training adaptations.

1) More capillaries, 2) greater recruitment of existing capillaries, 3) better blood-flow redistribution away from inactive areas, 4) increased total blood volume.

What two main mechanisms expand plasma volume after endurance training?

1) Increased plasma protein (especially albumin) synthesis raising oncotic pressure, 2) hormonal actions of ADH and aldosterone that promote renal water and sodium retention.

Why might hematocrit decrease even though red blood cell number rises with training?

Plasma volume expands more than red blood cell volume, diluting the blood and lowering hematocrit while reducing viscosity.

How does pulmonary ventilation change at rest, submaximal, and maximal intensities after training?

Rest: unchanged; Submax: decreases up to 30 %; Max: increases substantially (e.g., 100–120 L·min⁻¹ to 150 L·min⁻¹ or more).

What is exercise-induced arterial hypoxemia?

A drop in arterial oxygen saturation below ~96 % during intense exercise, due in part to reduced transit time of blood through the lungs.

How is pulmonary diffusion affected during maximal exercise in trained individuals?

It increases because pulmonary blood flow and ventilation are higher, engaging more alveoli for gas exchange.

Why does the (a-v)O₂ difference widen after endurance training?

Tissues extract more oxygen due to greater capillary density, higher mitochondrial content, and lower mixed-venous O₂.

Name the ‘master switch’ protein for mitochondrial biogenesis in skeletal muscle.

PGC-1α (peroxisome-proliferator-activated receptor-γ co-activator-1 alpha).

How does aerobic training affect myoglobin content in muscle?

It can increase myoglobin content by ~75–80 %, enhancing intramuscular oxygen transport.

What is glycogen sparing and why does it occur after aerobic training?

A reduced rate of muscle-glycogen utilization, owing to greater reliance on fat metabolism from enhanced mitochondrial function.

How does endurance training shift the lactate threshold?

It raises the workload or %VO₂ max at which blood lactate begins to accumulate rapidly, allowing higher sustainable intensities.

What happens to the respiratory exchange ratio (RER) at submaximal intensities after training?

RER decreases, reflecting a greater reliance on fat oxidation and reduced carbohydrate use.

Identify three factors that explain individual variability in VO₂ max improvements.

Initial training status, genetic heredity (25–50 % influence), and sex (women start lower but can approach men’s values when highly trained).

How do ‘high responders’ and ‘low responders’ differ in training adaptations?

High responders show large improvements in VO₂ max and performance with training, whereas low responders exhibit minimal gains, largely due to genetic and physiological factors.

Which laboratory test is most commonly used to assess anaerobic power?

The Wingate test, measuring peak power output during the first 5–10 s of all-out cycling.

Typical improvement range in anaerobic power following anaerobic training is _.

Approximately 10–25 %.

How does anaerobic training alter skeletal-muscle fiber type and size?

It preferentially recruits and enlarges type II fibers, increasing their cross-sectional area; type I fibers may also hypertrophy but to a lesser extent.

Describe adaptations in the ATP-PCr system after sprint training.

Increases in muscular strength and phosphocreatine availability enable maximal force production for <5 s with less effort.

Do short-term glycolytic adaptations primarily enhance ATP yield or strength?

Research suggests the primary benefit is improved strength, not an increased anaerobic ATP yield.

How do high-intensity interval training (HIIT) adaptations compare to continuous endurance training?

HIIT elicits many of the same cardiovascular and mitochondrial adaptations as traditional endurance training, often in less time.

Explain the principle of training specificity in relation to VO₂ max testing.

VO₂ max is highest when measured in the exercise mode used for training (e.g., runners test highest on treadmill, cyclists on cycle ergometer).

What is the main downside of combining heavy endurance and strength training (cross-training) for an athlete focused on strength gains?

Concurrent endurance work can blunt maximal strength and hypertrophy gains compared with strength-only programs, though it generally does not impair endurance development.