Module 1 Flashcards
What is exercise?
A single bout of physical activity.
What is training?
Multiple bouts of similar exercise over time (weeks, months, years).
What are the two basic types of exercise?
Aerobic and resistance exercise.
What is resistance exercise?
Lifting heavy things over and over again; high force output for a low amount of repetitions.
What is aerobic exercise?
Repetitive exercise with a high rate of energy turnover, low force, and long duration; stresses energy transfer and ATP production.
What are the expected changes in the body after resistance training?
Increased strength, muscle size (hypertrophy), and some crossover benefits.
What are the expected changes in the body after aerobic training?
Increased aerobic capacity, increased VO2 max, increased mitochondrial density, increased ATP generation capacity, and health benefits.
What is the functional unit of muscle contraction?
The sarcomere.
What are the steps involved in muscle contraction?
- Brain sends electrical signal.
- Motor neuron activates.
- Signal crosses neuromuscular junction (acetylcholine).
- Muscle fiber depolarization.
- Sarcoplasmic reticulum releases calcium.
- Calcium binds to troponin.
- Tropomyosin moves off actin binding sites.
- Cross-bridge cycling occurs, generating force.
What two key components are needed for muscle contraction?
Calcium (signal) and ATP (energy).
What are the products of ATP usage in muscle contraction?
ADP and inorganic phosphate.
What is the primary adaptation responsible for increased strength after training?
Hypertrophy (increased muscle size).
How does muscle hypertrophy increase strength?
By adding sarcomeres in parallel, increasing the number of cross-bridges.
How does the body control which muscle fibers or motor units are activated?
Through mechanisms of selective recruitment.
Which type of motor units are primarily recruited during low-intensity exercise?
Type 1 motor units/fibers.
What happens to muscle fiber recruitment as exercise intensity increases?
More muscle fibers, including Type 2a and Type 2x, are recruited.
What principle explains the order of motor unit recruitment?
The size principle.
How does the size of axons affect motor unit recruitment?
Type 1 motor units have smaller axons and are activated more easily, while Type 2 motor units have larger axons and require a stronger signal to be activated.
What are the characteristics of Type 1 muscle fibers?
Not super good at producing a lot of force, pretty slow in their contraction, really good at resisting fatigue and making the same force for a long time. More aerobic enzymes, more fat.
What are the characteristics of Type 2X muscle fibers?
Super strong, super quick, really bad at maintaining force. Fatigue really quickly. More anaerobic enzymes, more phosphocreatine.
What changes occur within the muscle during exercise?
- PO2
- NAD:NADH
- AMPK
- ROS
- Calcium
- Tension
How do changes within the muscle during exercise differ between aerobic and resistance exercise?
aerobic
* PO2
* NAD:NADH
* AMPK
* ROS
* Calcium
Resistance
* calcium
* tension
