Muscle Types and Endurance Quiz

Study Notes

Muscles are essential for bodily movement, energy expenditure, and overall wellness.
Muscular strength is the force a muscle can exert at maximum effort; muscular endurance is the ability to sustain repeated contractions.
Resistance training is key for developing both strength and endurance, often requiring professional guidance for optimal results.

Skeletal Muscle: Facilitates body movement; under conscious control.
Cardiac Muscle: Located in the heart; responsible for heart contractions.
Smooth Muscle: Found in various organs; controls involuntary movements like digestion and blood flow.

Skeletal muscles are linked to bones and enable limb, torso, and head movements.
Comprised of muscle fibers, which are individual muscle cells signaling contraction through nerve impulses.
Motor Units: The combination of a nerve and the muscle fibers it controls.

Type I (Slow-Twitch):
- High endurance and fatigue resistance, suited for prolonged activities.
- Contains more mitochondria, myoglobin, better blood supply, smaller size.
- Primarily uses aerobic metabolism.
Type II (Fast-Twitch):
- Larger size, less oxygen-dependent, more suited to short bursts of intense activity.
- Less fatigue resistant compared to slow-twitch fibers and can be sub-divided into Type IIa and Type IIb based on training influence.

Only found in the heart; contains actin and myosin for contraction, forming a striated appearance.
Cardiac muscle cells operate as a synchronized unit due to impulses from the sinoatrial node.

Spindle-shaped, smaller than skeletal muscle, and lacks sarcomeres, leading to non-striated appearance.
Capable of sustained contraction and applies consistent tension, called smooth muscle tone.

Exercise progression should prioritize large muscle groups before small ones, multi-joint before single-joint exercises, and higher intensity before lower intensity.
Training frequency recommendations vary by experience level:
- Novice: 2-3 days/week
- Intermediate: 4-5 days/week
Repetition maximums (RM) differ based on training phase, with an emphasis on allowing adequate rest between sets.

Strength Training: Light loads at 30-60% of 1 RM, emphasizing fast contraction velocity and multiple joint exercises.
Local Muscular Endurance Training: Light to moderate loads (40-60% of 1 RM), involving high repetitions with short rest periods.

Dynamic Constant Training (DCT): Applies constant resistance throughout the full range of motion.
Dynamic Progressive Training (DPT): Gradually increases resistance, often used in rehabilitation and suitable for portable exercises.
Dynamic Variable Training (DVT): Adjusts resistance to match muscle group strength variability throughout motion.
Isokinetic Training (IKT): Muscle contraction occurs at a constant speed, focusing on movement dynamics against resistance.

The ratio of slow-twitch to fast-twitch fibers varies by individual due to genetics.
Endurance athletes typically have more slow-twitch fibers, while sprinters have more fast-twitch fibers.
Training can modify the performance characteristics of both fiber types though inherent limitations remain.