1. Muscle Metabolism

2. Muscle Metabolism Muscles need a constant supply of ATP.
3 Sources of ATP
1. creatine phosphate
2. aerobic respiration
3. anaerobic respiration

4. 1. creatine phosphate + ADP → C + ATP
CP is a high energy compound stored in muscles in large amounts
CP reserves restored during inactivity by ATP not needed for muscle activity
ATP
ADP
Creatine
Phosphate + C +

5. glucose + O2 → CO2 + H2O + ATP energy
2. aerobic respiration
Requires Oxygen
glucose from bloodstream (from glycogen) → breaks down to release energy
glucose + O2 → CO2 + H2O + ATP energy

6. 3. anaerobic respiration
glucose → pyruvic acid w/out O2 → lactic acid + 2 ATP
occurs when circulatory system can no longer deliver enough O2
causes most pyruvic acid to change to lactic acid – makes muscles sore
most lactic acid diffuses from muscles into bloodstream
when O2 is available, lactic acid is reconverted to pyruvic acid and either oxidized or converted to glycogen

7. Although aerobic harvest 20x more ATP/ glucose, anaerobic produces its ATP 2x faster.
When large amounts of ATP are needed for moderate periods (30-40 sec.), the anaerobic can provide most ATP.
stored ATP + CP + LA glycolysis = high exertion for about 1 min.

9. Energy Systems Used During Various Athletic Activities
ATP and CP - used when activities require a power surge
last only a few seconds
ex: wt. lifting, diving, sprinting
anaerobic - sustained, less vigorous activities
ex: tennis, soccer, 100m swim, soccer
aerobic - prolonged activities that need endurance, no power
ex: marathon runs, jogging

10. Muscle Fatigue when ATP production cannot keep pace with ATP use
when muscles fatigue, they do not respond to stimuli (cross bridges do not detach)

11. Other Fatigue Factors Include:
Lactic acid build up
not due to inadequate gas but heart can’t keep up or muscles can’t handle more O2
Ionic imbalance of Na+ - K+ pump
in absence of ATP, pump doesn’t work right, active transport
Oxygen debt

12. Oxygen Debt incurred during anaerobic respiration must be repaid
extra amounts of O2 must be taken in by the body to provide for restorative processes

13. Oxygen Debt Increased breathing reduces oxygen debt
represents the difference between the amount of oxygen that would be needed for totally aerobic respiration during muscle activity and the amount that is actually used
Increased breathing reduces oxygen debt

14. All or None Response
muscle fibers contract to the full extent of their ability or not at all

15. Speed and Duration of contraction depends on:
1. size of load
greater loads = slower contraction
2. muscle fiber type
slow twitch - slow but fatigue resistance
fast twitch - quick but tire (need more oxygen)
fast twitch - quick but resistant to fatigue
Muscles are a mix of fast and slow (% is genetic).

16. Muscle Hypertrophy Endurance does not promote hypertrophy.
Hypertrophy is from high resistance exercises.
# of myofibrils increases

17. Muscle Atrophy Immobile muscles will atrophy.
# of myofilaments decreases

18. Effects of Aerobic and Resistance Exercise on muscles and other body parts
capillaries around muscles increase
mitochondria increase
less fatigue
increase in strength
body more coordinated
improved digestion
skeleton stronger
improved cardiovascular system
burns more calories