Unit 1 Exam

Principles of Weight Training

Muscle Fiber

A single muscle cell that contains myofibrils.

Motor Unit

One motor neuron and all muscle fibers it controls.

Myofibrils

Contractile structures inside muscle fibers made of sarcomeres.

Myosin

Thick filament with heads that bind actin and use ATP.

Actin

Thin filament attached to Z-lines.

Sarcomere

Functional unit of muscle contraction between two Z-lines.

Z-line

Boundary of a sarcomere where actin attaches.

Action Potential

Electrical signal that triggers muscle contraction.

Sliding Filament Theory

Theory that describes muscle contraction through the sliding of myofilaments.

Calcium role in contraction

Exposes actin binding sites by moving tropomyosin.

ATP role in contraction

Powers cross-bridge cycling and detachment.

Power Stroke

Myosin pulls actin toward the sarcomere center.

Muscle Relaxation

Occurs when calcium is pumped back into the sarcoplasmic reticulum.

All-or-none Principle

A muscle fiber contracts fully or not at all.

Recruitment

Activation of additional motor units to increase force.

Type I Fibers

Slow, aerobic, fatigue-resistant, used for endurance.

Type IIa Fibers

Fast, with moderate endurance and power.

Type IIb (IIx) Fibers

Fastest, most powerful, and fatigue quickly.

Proprioceptors

Sensory receptors that sense body position and movement.

Muscle Spindle Function

Detects change in length and speed of stretch of the muscle

Golgi Tendon Organ Function

Monitor forces in the muscle body at tendon and cause relaxation. Prevent your from tearing something

Biomechanics

Study of forces and motion in the human body.

Proximal vs Distal

Proximal = closer to trunk; Distal = farther away.

Axial Skeleton

Includes the skull, spine, and rib cage.

Appendicular Skeleton

Includes arms, legs, and girdles.

Agonist Muscle

Known as the prime mover.

Antagonist Muscle

Opposes the prime mover.

First-class Lever Example

Neck extension.

Second-class Lever Example

Calf raise.

Third-class Lever Example

Biceps curl.

Concentric Action

Muscle shortens.

Eccentric Action

Muscle lengthens under tension.

Isometric Action

Muscle tension without movement.

Negative Work

Force applied opposite the direction of movement.

Strength Definition

Maximum force a muscle can produce.

Strength-to-mass Ratio

Strength relative to body weight.

Valsalva Maneuver

Breath holding to stabilize the spine.

Weightlifting Belt Usage

Used during near-maximal or maximal lifts.

Purpose of Knee Wraps

Joint support and elastic assistance.

Catabolism

Breakdown of large molecules to smaller ones to release energy.

Anabolism

Building of larger molecules from smaller ones, happens when energy release from catabolic reactions

ATP

Primary energy source of the cell.

Phosphagen System Duration

0–10 seconds.

Primary Fuel of Phosphagen System

ATP and phosphocreatine.

End Product of Glycolysis

Pyruvate.

ATP from Glucose vs Glycogen

Glucose = 2 ATP, Glycogen = 3 ATP.

Two Fates of Pyruvate

Can enter oxidative system or convert to lactate.

Cori Cycle

Lactate is converted to glucose in the liver, then used by muscles.

Lactate Threshold

Point during exercise when body tires quickly due to lactic acid build up

OBLA

Fixed blood lactate level (~4 mmol/L).

Oxygen Deficit

Oxygen shortfall at the start of exercise.

EPOC

How quickly you get back to baseline or how quick you recover

Interval Training

Alternating periods of work and rest.

HIIT

High-Intensity Interval Training with very high-intensity bursts.

Combination Training

Training that incorporates multiple energy systems.