Chapter 7 - Lesson 3

Question 1

What are the 3 different types of muscle actions?

Answer 1

Isotonic, Isometric and Isokinetic

Question 2

Isotonic muscles can be divided into what 2 sub categories?

Answer 2

concentric (contract) - muscle becomes shorter

eccentric (extend) - muscle becomes longer

Question 3

Isotonic muscle contraction

Answer 3

Force is produced as a muscle develops tension while visibly changing in length. Composed of concentric and eccentric and represent the lowering and lifting of resistance training. Think of a DB bicep curl

Question 4

Eccentric muscle action

Answer 4

A muscle action that occurs when a muscle develops tension while lengthening. They actions require less energy to complete a task. Often referred to as “negative work” - also these movements go in the same direction as resistance

Like lowering a DB back down to your side while doing a bicep curl

Question 5

Motor Unit

Answer 5

A motor neuron and all of the muscle fibers that it innervates.

Question 6

Concentric muscle action

Answer 6

A muscle action that occurs when a muscle is exerting force greater than the resistive force, resulting in a shortening of the muscle. Often referred to as “positive work” - the joint moves through a ROM to move a load against the pull of gravity.

Like lifting a DB up towards your shoulder while doing a bicep curl

Note - this is when the actin and myosin slide past one another

Question 7

Isometric muscle contraction

Answer 7

When a muscle is exerting force equal to the force being placed on it leading to no visible change in the muscle length. An example would be a plank, a static curl, or pausing during an exercise.

Question 8

Core

Answer 8

The structures that make up the lumbo-pelvic-hip complex (LPHC), including the lumbar spine, pelvic girdle, abdomen, and hip joint.

Question 9

Isokinetic muscle contraction

Answer 9

During isokinetic muscle actions, the muscle shortens at a constant speed over the full ROM.

An isokinetic muscle action requires the use of expensive and sophisticated equipment that measures the amount of force generated by the muscles and adjusts the resistance (load) so that no matter how much muscular tension is produced, movement speed remains constant.

Question 10

Muscle action spectrum

Answer 10

The full range of eccentric, isometric, and concentric muscle contractions required to perform a movement.