Motor Learning Lecture 2: Muscle Fibers/Contractions

What type of muscle fiber have few mitochondria and have high strength but low endurance?

fast glycolytic

What do fast glycolytic fibers look like?

large white fibers

What type of muscle fiber has many mitochondria and can produce mid-level force and endurance?

fast oxidative

What do fast oxidative fibers look like?

medium sized pink/red fibers

What type of muscle fibers have many mitochondria with high endurance but low strength output?

slow oxidative

What do slow oxidative muscle fibers look like?

small thin dark red fibers

Which muscle contraction is characterized by generating force while shortening?

concentric

What is the function of concentric muscle contraction?

produces movement against resistance

Which muscle contraction generates force while being lengthened?

eccentric

What is the purpose of eccentric muscle contractions?

movement control while resisting gravity

Which muscle contraction generates force without a change in length?

isometric

What is the purpose of isometric muscle contractions?

stability and posture

At what percent of a muscle’s resting length would be considered too short to generate ideal force output?

~80% or less

At what percent of a muscle’s resting length would be considered too long to generate ideal force output?

~120% or more

At what percent of a muscle’s resting length would be considered optimal to generate ideal force output?

~75-110%

What tis the result of a sarcomere which is less than the optimal range for force output?

too much actin filament overlap

What tis the result of a sarcomere which is more than the optimal range for force output?

not enough actin/myosin overlap