Chapter 4

• individual muscle cell, each cell contain multiple nuclei • bundle of fascicles • single muscles are made up of multiple fascicles • held together by connective tissue

strength, speed of contraction, and energy source

myofibrils

• contractile unit of myofibril • composed of actin and myosin molecules • contraction are produced when the myosin glides across the actin

myofibrils increase in size and number

increased number of fibers instead of larger size

decrease in muscle fiber size

fatigue resistant slower contraction than fast-twitch primarily fueled by aerobic system reddish color

rapid and forceful contraction fatigue quickly primarily fueled by anaerobic system preferentially increased with training whitish color

nerve connected to muscle fibers a small unit is slow twitch, a large unit is fast twitch. The number of units recruited is dependent on the amount of strength needed

covered in myelin and the more motor skills causes more myelin to lay down on the axon. This improves neural conduction and improves skills

muscle learning: increases strength maintain motor nerve connections decrease bone loss when practiced regularly

improves glucose metabolism increases vo2max lowers blood pressure increases HDL and lowers LDL blood vessel health

strength: 1 rep max endurance: counting maximum reps of an exercise

isometric contraction important for developing core muscles for support of spine and torso and useful after injury to improve strength with minimal movement

muscle contracts and changes the length of the joint best for gaining strength that can be translated to other physical activity

shortens as enough force is applied to overcome resistance

lengthens when resistance is greater than the force applied

Constant: constant load is applied throughout full range of motion Variable: load changes to provide maximum load throughout the range of motions

eccentric loading, plyometrics, speed loading, isokinetic loading

load is placed as the muscle lengthens Negatives: specifically used to overload the muscle eccentrically

eccentric loading and stretching followed by forceful contraction explosive strength, maintain bone density

move weight as quickly as possible

exerting force at a constant speed against equal force