PE 116 Chapter Notes - Chapter 4: Motor Unit, Myofibril
19 Jun 2018
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Muscular strength is the amount of force a muscle can produce with a single maximum
effort.
Muscular endurance is the ability of a muscle or muscle group to contract repeatedly
over a period of time.
Well-trained muscles can assist with:
Daily living
Protection from injury (i.e. low-back pain)
Good quality of life
Basic Muscle Physiology
Muscles consist of individual muscle fibers (cells) connected in bundles
Muscle fibers are made up of smaller protein structures called myofibrils
Proper strength training causes individual fibers to increase the number of myofibrils,
resulting in hypertrophy
What are Motor Units?
A motor unit is made up of a nerve connected to a number of muscle fibers
Motor unit recruitment is the process when strength is required, nerves assist with
the action
The number and type of motor units recruited are dependent upon the amount of
strength required
The ability to improve the body’s ability to recruit motor units is known as muscle
learning
Benefits of Muscular Strength and Endurance:
Improved Performance of Physical Activities
Injury Prevention
Improved Body Composition
Improved Metabolic and Heart Health
Enhanced Self-Image and Quality of Life
Improved Muscle and Bone Health with Aging
Prevention of Chronic Disease
Physiological Changes from Strength Training:
Increased muscle mass
Increased coordination of motor units
Increased strength of tendons, ligaments, and bones
Increased storage of fuel in muscles
Increased size of fast-twitch muscle fibers (heavier loads)
IIncreased delivery of oxygen and nutrients
Biochemical improvements (increased insulinsensitivity)
Document Summary
Muscular strength is the amount of force a muscle can produce with a single maximum effort. Muscular endurance is the ability of a muscle or muscle group to contract repeatedly over a period of time. Muscles consist of individual muscle fibers (cells) connected in bundles. Muscle fibers are made up of smaller protein structures called myofibrils. Proper strength training causes individual fibers to increase the number of myofibrils, resulting in hypertrophy. A motor unit is made up of a nerve connected to a number of muscle fibers. Motor unit recruitment is the process when strength is required, nerves assist with the action. The number and type of motor units recruited are dependent upon the amount of strength required. The ability to improve the body s ability to recruit motor units is known as muscle learning. Increased size of fast-twitch muscle fibers (heavier loads)
