Effects of Exercise on Skeletal Muscle

A little Background Information

Benefits

• Improved muscle tone

• Better posture• More efficient heart

& lung function• Less fatigue• Looking & feeling

better

Changes in Muscle Mass

NOT an INCREASE or DECREASE in Muscle Fiber

number

Atrophy• Shrinking in

mass • Due to

prolonged inactivity & disuse

Hypertrophy• Increase in

muscle mass & size

• Due to exercise & use of the muscle

Changes to Muscle

• Strength Training – Contracting against

resistance– Enhances hypertrophy– This is anaerobic– Increases the number of

myofilaments in each muscle fiber

– The number of muscle fibers does NOT change

Changes to Muscle• Endurance training

– Increases the muscle’s ability to sustain exercise over a long period of time & is aerobic

– Usually does not result in hypertrophy• Increases the number of blood

vessels & mitochondria• This allows for more efficient

delivery of O2 & glucose and greater production of ATP

Exercise and Muscle Tissue

What are the 4 physiological effects of exercise?

• Improved muscle tone • Improved Posture • Better Heart and Lung function • Less Fatigue

What is are the psychological effects of exercise?

• Improved Looks• Improved Self Image

What happens when a muscle is not used?

• They Atrophy – Shrink or get smaller

Identify a “legitimate” reason for inactivity

• Disease• Injury

Identify a “bogus” reason for inactivity

• Laziness– Couch Potato

What happens to muscle mass with repeated exercise?

• Muscle increases in mass – Hypertrophy

What happens physiologically to muscle during strength training?

• Increased myofilaments which… • Increases muscle fibers which… • Increases muscle mass which… • Increases strength

What is the difference between strength training and endurance

training?

• Strength training increases overall skeletal muscle – strength and bulk

• Endurance training is aerobic – increases muscle endurance

What types of muscle contractions are typically associated with

strength training? Endurance training?

• ST = Isometric• ET = Isotonic

What happens physiologically to muscle tissue with aerobic training?• Increases blood vessels which… • Increases blood flow which… • Increases nutrients / oxygen / waste

removal which… • Increases efficiency

What type of muscle(s) is/are improved with strength training?

• Skeletal

What type of muscle(s) is/are improved with aerobic training?

• Cardiac, Smooth