6) muscle phys part 2 - endurance

capillaries live in

the endomysium (connective tissue) of skeletal muscle

type 1 fibers oxidative capacity

high oxidative capacity - large mitochondrial content, capillary dense

diameter (diffusion distance)

A smaller distance is more efficient

type I and type IIa have smaller distances, better for oxidative capacity

myoglobin function

stores oxygen

type IIa and type IIb have high SR Ca pumping capacity because

They need to be able to reset quickly and activate quickly

at low intensity exercise we tend to rely on

plasma free fatty acids

at high intensity exercise we tend to rely on

muscle glycogen

the longer the duration of exercise, the more

free fatty acids are being utilized and driving the adaptations we want

- stresses all systems

low-load, long-duration exercise adaptations

increased number of mitochondria and membrane area

increased number of capillaries

increased myoglobin content

decrease CSA of all fiber/motor units recruited

HIIT (high intensity interval training)

increased mitochondrial enzymes

increased VO2 max

localized vs systemic changes

one-arm ergometry

85% of arm VO2 max

ten weeks

increased local VO2 max

no systemic change