GENERATING FORCE Flashcards
What is the Yield Point
Marks the end of the elastic behavior of a muscle and starts the plastic behavior where it gets permanently damaged.
What is the Effect of Loading
Objects deform when subjected to external forces
Under small loads, an object may show…
Elastic Behavior (Bend but not break)
EX: object will deform but when load is taken off, object will return its shape
Under larger loads, an object may show…
Plastic Behavior (Permanent Damage)
EX: external forces above a certain size will cause deformation
Stiffness is rigidity of an object OR….
Desire to remain elastic
What is Hill’s Muscle Model
Explains the behavior of a musculotendinous unit
3 sites that develop force within a muscle
CONTRACTILE:
site where force generation occurs (sarcomeres)
ACTIVE COMPONENT
ELASTIC COMPONENT:
as muscle lengthens tendons stretch
PASSIVE COMPONENT
PARALELL ELASTIC COMPONENET
as muscle lenthens connective tissue inside muscle stretch
stretch contributes to force development
PASSIVE COMPONENT
What is Plyometrics?
Exercises where muscles exert maximum force in short-intervals of time
The goal is to increase power (speed-strength)
What is the Stretch-Shorten Cycle?
Stretch Shorten Cycle=active stretch (ECCENTRIC) followed by immediate CONCENTRIC action
Principle of Plyometrics
Example of Hill’s Muscle model
How is the Stretch -Shorten Cycle an example of Hill’s Muscle Model?
- the length of the tendon increases due to active stretch
- elastic component stores energy like a spring
- this energy is released as tendon shortens
- creates efficient movement
- more force is porduced at lower energy cost
What is a twitch
A small, localized contraction and relaxation
What are the mechanical functions of the SKELETAL system?
-The human skeletal system consists of bones, cartilage, ligaments and tendons and accounts for about 20 percent of the body weight
- provide rigid framework
- support and protect internal organs
What are the mechanical functions of the MUSCULAR system?
- attach to the skeletal system to create movement
- posture
- joint stability
- heat production
Force-Velocity Relationship
The faster a muscle lenthens, the more force it can generate
Power-Velocity Relationship
Power=product of muscular force and shortening velocity
Power=ability to travel great speed or force
Max power occurs at 30% maximum velocity of shortening
Lenth-Tension Relationship
Force generated by muscle is influenced by amount of overlap in sarcomeres
Muscles often cross more than one joint
Change in joint psoition=change in muscle length
ACTIVE INSUFFICIENCY: failure to produce force when muscles are slack ex: decreased ability to form a first with wrist in flexion
PASSIVE INSUFFICIENCY: restriciton of joint range of motion when muscles fully stretched ex; decreased ROM at wrist when fingers extended
