CHAPTER 4 Muscular Strength and Endurance

Vocabulary flashcards covering key terms from the notes on muscular strength and endurance, including physiology, training concepts, and safety.

hypertrophy

An increase in the size of muscle fibers, usually stimulated by muscular overload during strength training.

hyperplasia

An increase in the number of muscle fibers; in humans, not thought to play a significant role in muscle size.

atrophy

A decrease in the size of muscle fibers, usually due to inactivity.

myofibril

Smaller protein structures that make up muscle fibers and contribute to contraction.

sarcomere

Contractile units within a muscle fiber, largely made of actin and myosin.

satellite cells

Cells that provide additional nuclei to muscle fibers, enhancing repair and protein synthesis.

slow-twitch muscle fibers

Red, fatigue-resistant fibers (Type I) that rely on aerobic metabolism and contract more slowly.

fast-twitch muscle fibers

White fibers (Type II) that contract rapidly and strongly but fatigue quickly; rely more on anaerobic metabolism.

motor unit

A nerve connected to several muscle fibers; recruitment increases with greater force.

axon

A long nerve fiber that conducts impulses away from the nerve cell body.

myelin

Fatty insulating layer around an axon that speeds neural conduction.

motor learning

The improvement in the nervous system’s ability to recruit motor units through practice.

isometric (static) exercise

A contraction without a change in muscle length or joint angle.

isotonic (dynamic) exercise

A contraction with movement; includes concentric and eccentric phases.

concentric

Muscle shortens as it contracts.

eccentric

Muscle lengthens under tension during contraction (negative phase).

isokinetic

Contraction at a constant speed with variable resistance provided by a machine.

constant resistance

A fixed load throughout a joint’s range of motion (e.g., free weights).

variable resistance

Load changes to provide maximum effort through the range of motion (e.g., some machines).

plyometrics

Exercises involving rapid stretching of a muscle followed by a forceful contraction to develop power.

speed loading

Moving a weight as rapidly as possible to develop neuromuscular power.

kettlebell

A cast-iron weight with a handle used for ballistic, dynamic training.

suspension training (TRX)

Bodyweight resistance training using suspension straps attached to an anchor.

blood flow restriction training (KAATSU)

Training with restricted blood flow to working muscles to promote hypertrophy.

FITT principle

Framework of Frequency, Intensity, Time, and Type used to design a program.

1RM (one-repetition maximum)

The maximum weight that can be lifted for a single repetition.

RM (repetition maximum)

The maximum resistance that can be moved for a specified number of repetitions.

rest interval

The recovery period between sets; typically 1–3 minutes for general fitness and 3–5 minutes for heavy lifting.

volume

Training volume equals weight × repetitions × sets; used to gauge overall workload.

progression

Systematic increases in training stimulus to elicit continued gains.

warm-up

5–10 minutes of light activity to prepare the body for exercise; include activity-specific warm-ups.

cool-down

5–10 minutes of light activity to transition the body to resting state; may include stretching.

overtraining

Excess training without adequate recovery; signs include fatigue, plateau, and performance decline.

spotter

A person who assists with free-weight lifts to enhance safety.

collars

Devices that secure weight plates on a barbell to prevent slipping.

protein supplements

Protein or amino acid supplements; timing around workouts may support growth but are not always superior to whole foods.