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PHED 2

PHED 101: Muscle Fitness

Different types of Muscle

Types of Muscle

  • Cardiac Muscle

    • Striated

    • Involuntary

  • Skeletal Muscle

    • Striated

    • Voluntary

  • Smooth Muscle

    • Non-striated

    • Involuntary

Muscle Anatomy Simplified

  • Sarcomere: The smallest functional unit of a muscle that contracts.

Different Types of Muscle Fibers

  • Slow Twitch Muscle Fiber

  • Fast Twitch Muscle Fiber

  • Humans typically possess a mix of both fiber types within bundles named fascicles.

Why is slow -twitch muscle fiber red?

they are based on endurance which requires oxygen for aerobic respiration. Oxygen is stored in muscle in form of myoglobin.

Myoglobin: is an oxygen and iron binding protein found within muscle fiber (oxygen + iron +water = rust)

Slow-Twitch vs Fast-Twitch Muscle Fibers

Characteristics of Slow-Twitch Muscle Fibers

  • Efficient in using oxygen.

  • Suitable for endurance sports (cycling, marathon running).

  • delayed muscle firing.

  • Do not tire easily.

Characteristics of Fast-Twitch Muscle Fibers

  • Do not burn oxygen to create energy.

  • Fast to fire and best for explosive movements (sprinting, weightlifting).

  • Tire out quickly.

  • Suited for short: short bursts of activity, sprinting races, pole vaulting and cross fit-style event.

Strength Training and Muscle Fiber Type

Types of Muscle Fibers Overview

  • Fast Twitch Fibers:

    • Heavy weights

    • 5-10 rep range

    • 90-180 sec rest

  • Slow Twitch Fibers:

    • Light weights

    • 12-30 rep range

    • 30-60 sec rest

Types of Muscle Contractions

  • Isometric Contraction: without motion used to stabilize a joints.

  • Concentric Contraction:cause tension on your muscle as it shortens. It creates enough force to move an object. This is most popular type of contraction. Usually movements against gravity.

  • Eccentric: causes tension on your muscle as it lengthens. Usually movement with gravity.

Muscle Capacity Definitions

  • Muscle Strength: how much you lift.

  • Muscle Endurance: how many reps and sets.

  • Muscle Power:how fast you can finish reps and sets.

  • Flexibility: Range of motion in joints.

Muscle Hypertrophy

Hypertrophy occurs when resistance training provides overload with heavy weights and low repetitions, increasing size and number of myofibrils in muscles.

  • Muscle fiber

  • Sarcoplasmic hypertrophy: increased pressure or water inside muscle.

  • Myofibrillar hypertrophy: increased protein.