METABOLIC ADAPTATIONS TO EXERCISE

1. CHAPTER 6 CHAPTER 6 METABOLIC ADAPTATIONSTO EXERCISE METABOLIC ADAPTATIONSTO EXERCISE

2. Aerobic vs Anaerobic Training Aerobic (endurance) training leads to w Improved blood flow, and w Increased capacity of muscle fibers to generate ATP. Anaerobic training leads to w Increased muscular strength, and w Increased tolerance for acid-base imbalances during highly intense effort.

3. . w Improved submaximal aerobic endurance and VO2max Adaptations to Aerobic Training w Muscular changes in fiber size, blood and oxygen supply, and efficiency of functioning w Improved efficiency of energy production

4. Muscular Adaptations w Increased size of ST fibers w Increased number of capillaries supplying the muscles w Increased myoglobin content of muscle (allowing muscle to have more oxygen) w Increased number, size, and oxidative enzyme activity of mitochondria

5. Adaptations Affecting Energy Sources w Trained muscles store more glycogen and triglycerides than untrained muscles. w FFAs are better mobilized and more accessible to trained muscles. w Muscles’ ability to oxidize fat increases with training. w Muscles’ reliance on fat stores first conserves glycogen during prolonged exercise.

6. USE OF ENERGY SOURCES WITH INCREASING INTENSITY

7. Volume w Frequency of exercise bouts w Duration of each exercise bout Intensity w Interval training w Continuous training Aerobic Training Considerations

8. w Athletes who train with progressively greater workloads eventually reach a maximal level of improvement beyond which additional training volume will not improve endurance or VO2max. . Training Volume w Volume is the load of training in each training session and over a given period of time. w Adaptations to given volumes vary from individual to individual. w An ideal aerobic training volume appears to be equivalent to an energy expenditure of about 5,000 to 6,000 kcal per week.

9. . TRAINING VOLUME AND VO2MAX

10. Training Intensity w Muscular adaptations are specific to the speed as well as duration of training. w Athletes who incorporate high-intensity speed training show more performance improvements than athletes who perform only long, slow, low-intensity training. w Aerobic intervals are repeated, fast-paced, brief exercise bouts followed by short rests. w Continuous training involves one continuous, high-intensity exercise bout.

11. Adaptations to Anaerobic Training w Increased muscular strength w Slightly increased ATP-PCr and glycoytic enzymes w Improved mechanical efficiency w Increased muscle oxidative capacity (for sprints longer than 30 s) w Increased muscle buffering capacity

12. Muscle Buffering Capacity w Anaerobic training improves muscle buffering capacity, but aerobic training does little to increase the muscles' capacity to tolerate sprint-type activities. w Improved muscle buffering capacity allows sprint-trained athletes to generate energy for longer periods before fatigue limits the contractile process.

13. Selected Muscle Enzyme Activities (mmol g min ) for Untrained, Anaerobically Trained, and Aerobically Trained Men . . -1 -1 Anaerobically Aerobically Untrained trained trained Aerobic enzymesOxidative systemSuccinate dehydrogenase 8.1 8.0 20.8Malate dehydrogenase 45.5 46.0 65.5Carnitine palmityl transferase 1.5 1.5 2.3 Anaerobic enzymesATP-PCr systemCreatine kinase 609.0 702.0 589.0Myokinase 309.0 350.0 297.0Glycolytic systemPhosphorylase 5.3 5.8 3.7Phosphofructokinase 19.9 29.2 18.9Lactate dehydrogenase 766.0 811.0 621.0 a a a a a a a a Denotes a significant difference from the untrained value.

14. . w Repeated measurements of VO2max Methods of Monitoring Training Changes w Lactate threshold tests w Comparing lactate values taken after steady-state exercise at various times in the training period