unit 2

Biomechanics

• Application of physics to human motion and analysis of human movement.

Muscular strength

• Amount of force a muscle can produce in a short period of time

Muscular endurance

• Ability of a muscle to stay contracted, or exert force against resistance, over an extended period of time.

• Ex: Doing multiple repetitons of an exercise

Benefits of muscular strength and endurance

• improves body composition

• slows bone density loss

• improves performance of physical activities

• reduces risk of injuries

Types of muscle fibers

• Type 1- slow twitch

• Type 2A- fast twitch

• Type 2B- fast twitch

Types of contractions

• concentric-muscles fibers shorten and muscles force is greater than resistance

• eccentric- muscle fibers lengthen and muscle force is less than resistance

• isometric- muscle fibers do not change in length and muscle force is equal to resistance

Levers

• Rigid structure (bone) with a force acting on it (muscle) to produce a turning movement (usually a joint)

• Levers move on a fixed point, the fulcrum.

Components of levers

• Load - Weight of body

• Effort - Provided by muscle

• Fulcrum - A fixed point (joint)

Types of levers

• 1st class- the fulcrum is between the load and the effort.  An example would be the head and neck joint; tilting the head back.

• 2nd class- the resistance or load is in the middle, with the fulcrum on one end and effort on one end.  An example would be the ankle joint; raising heel off the ground.

• 3rd class- the effort is in the middle with the load on one end and the fulcrum on on end. An example would be the forearm; flexing elbow.

When analyzing movement, look for the following:

1. Patterns of movements/type of muscles contracts (eccentric, concentric, isometric)

2. Joints involved in movement (For example: running uses the hip, knee, and ankle)

3. Muscles used in movement

4. Action performed

5. Select exercises to match the range of motion and pattern of movement for training