The Science of Sprinting and Distance Running

1. The Science of Sprinting and Distance Running A closer look into the physiology of runners

2. Strength vs. Endurance • Sprinting is based on muscle strength • Long distance running requires endurance • Strength is the ability to do something that uses a lot of energy for a short period of time • Endurance is the ability to do something that takes less energy for a longer amount of time

3. Lactic Acid • Mitochondria use lactic acid to provide energy to skeletal muscles • Endurance training reduces the level of lactic acid in an athlete’s blood even though their cells are still producing lactic acid • Sprinting training requires quick bursts of energy

4. Muscle Fibers • All muscles contain hundreds of fibers • Fibers connect to an axon • Many axons are connected to form a motor neuron • A single motor neuron may have hundreds of axons • As you train for whichever event you do, the brain needs to create more contractions which causes more “motor units” to be formed

5. “Fast-Twitch” vs. “Slow Twitch” • Whether a person has fast-twitch or slow-twitch muscles is based on which genes you get • There is no science yet to prove that fast-twitch muscles can be improved by training, leaving your sprinting ability to chance

6. Fast-Twitch Muscles • Fast-twitch muscles are important to sprinters • Fast-twitch muscles are made of white fibers • They have a high anaerobic capacity to allow lots of power to develop in a short period of time • They tire very quickly

7. Slow-Twitch Muscles • They are important to endurance athletes • These muscles are red because of the blood that is being pumped to them constantly • Better suited for aerobic activities

8. Lactate Threshold • The highest steady rate of intensity an athlete can maintain for a period of time • Lactate thresholds are measured in VO2 max • The lactate threshold is also a line between anaerobic and aerobic respiration- the point at which you need to start using aerobic energy sources

9. Lactate Threshold

10. VO2 MAX • The maximal amount of oxygen transported to the muscles to support • The VO2 max depends on the activity that you are doing- it would be different for running vs. biking • It can change for time to time due to different factors like sickness, training, racing, etc. • As the VO2 max changes, so will the lactate threshold

11. ATP • To run fast the muscles need to contract • In order for the muscles to contract they must have a source of energy • ATP is the body’s main source of energy • When hydrolysis occurs the bonds in the ATP break to provide the energy • ATP can be depleted within 1-2 seconds unless it is recharged

12. Recharging ATP Three main sources of resynthesis

13. Anaerobic Alactic • Creatine phosphate is used as an immediate replacement of ATP • By taking a phosphate from the creatine phosphate, the ADP can be turned into ATP • This process can continue until all of the creatine phosphate is depleted • This can create about 4-5 seconds of ATP reproduction, making this a good way for sprinters to account for their energy

14. Anaerobic Lactic • This occurs after all of the creatine phosphate is used up • This next process uses glycolysis • The glucose is broken down into two forms: glucose that can be used freely, and ATP • If the glucose is stored in the muscles or liver it takes the form of glycogen • Glycogen can be broken down into 3 ATP molecules • This energy source is abundant and allows high levels of activity, but it is limited in duration

15. Aerobic Energy • Used in the case of endurance athletes and long distance runs • Uses oxygen to create ATP • A pyruvate from glycolysis and fatty acids is turned into acetyl-CoA and oxidized into carbon dioxide and water- the Krebs Cycle • ATP is produced throughout the Krebs cycle, creating a source of energy • This can last for long periods of time

16. Energy Sources