- filament = - when a muscle contracts its a series of thousands of small units (sarcomeres) shortening - when sarcomere contracts the thin actin filaments are moved past the think myosin filaments - this results in a larger region of overlaps between the two sets of filaments, and causes the overall length of the sarcomere to shorten
The motor neuron and all the muscle fibers it innervates.
The different types of muscle actions and how do they differ from one another?
- ISOmetric (Muscle Tension = Muscle Load); tension is developed in the muscle with no change in muscle length - no movement.
- CONcentric Muscle Tension > Muscle Load; Muscle shortens while developing tension - movement
- ECCentric Muscle Tension < Muscle Load; muscle is trying to shorten but is being forced to lengthen - movement
DOMS and what causes it...
Delayed Onset Muscle Sorenes = Eccentric contration (an performing exercises which the body is not used to) is assicoated with DOMS. - worse 24-48 hours after workout - thought to be microscopic tears (microtrauma) to the muscle and swelling in and arouind the muscle
- also called dynamic contractions/actions - Joints are moved through full ROM - Concentric and Eccentric are isotonic - Free weights and machines - force exerted by the muscle is not constant; it varies according to the mechanical advantage of the joint
- Contrations during which a muscle contract and shortens at a constant speed - Requires special equipment that detects when muscle is speeding up and increases the load to slow down again - rehab settings
- muscle contracts but doens not shorten (giving no movement) - used to develop static strength - muscle gains strength only at the angle you use in the exercise - isometric training is not sufficient on its own; you need to combine it with isotonic training - causes an increase in blood pressure and decrease in blood flow to heart (not recommended for clients with heart disease or high blood pressure
Muscle Fiber Types
Born with a predetermined amount of these... - Type 1 ("slow twitch" or "slow oxidative") - Type II A ("intermediate" or "fast oxidative") - Type II B ("fast-twitch" or "fast-glycolytic fibers") - don't use
Type 1 ("slow twitch" or "slow oxidative") - small
- small (fiber size) - aerobic (predominant energy system) - slow (speed of shortening) - good (resistance to fatigue) - endurance (primary usage)
Type II A ("intermediate" or "fast oxidative")
- intermediate (fiber size) - intermediate (predominant energy system) - intermediate (speed of shortening) - moderate (resistance to fatigue) - moderate activity (primary usage)
Type II B ("fast-twitch" or "fast-glycolytic fibers") - don't use
- large (fiber size) - anaerobic (predominant energy system) - fast (speed of shortening) - poor (resistance to fatigue) - speed and power (primary usage)