Sports physiology

Musculoskeletal and neural system mechanism

1. National Sports Day 1

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4. SPORTS PHYSIOLOGY

5. Definition Sports physiology is the study of the long and short-term effects of training and conditions on athletes. It’s a specialized field of study that goes hand in hand with human anatomy and physiology Anatomy = Structure of the body Physiology = Function of the body 5

6. Sports physiology is a discussion of the ultimate limits to which several of the bodily mechanisms can be stressed . high fever 100 % in metabolism marathon race 2000 % in metabolism 6

7. WHICH BODY MECHANISMS? MUSCULAR SYSTEM NEURAL SYSTEM HORMONAL SYSTEM CARDIOVASCULAR SYSTEM RESPIRATORY SYSTEM 7

8. MUSCLE FORCE (STRENGTH) Strength of the muscle is determined mainly by its size i.e. cross sectional area of the muscle Maximal contractile force 30-40N/cm 2 World class weight lifter has a maximum cross sectional area of 150 cm 2 of quadriceps muscle Therefore, Maximal contractile force of quadriceps will be 4500-6000N i.e.nearly 525 kg rupture & avulsion of tendons, displaced cartilages , compression fractures and torn ligaments 8

9. Holding strength (force) of muscles: F orce that attempts to stretch out already contracted muscle G reater about 40% than contractile strength F(quadriceps)= 6300-8400N I nternal tearing in the muscle 9

10. Power of Muscular Contraction: Power is total amount of work that the muscle performs in a unit period of time. Unit – Kg.m /min determined not only by the strength but also: distance of contraction and the number of times that it contracts each minute Person has capability of extreme power surges for short periods Eg . 100m dash that is completed within 10 sec 10 First 8 to 10 seconds 7000 Kg.m /min Next 1 minute 4000 Next 30 minutes 1700

11. E ndurance Depends on amount of glycogen that has been stored in the muscle before the period of exercise Enhanced by high carbohydrate diet Eg . Running a marathon 11 Nutrition Time (min) High Carbohydrate diet 240 Mixed diet 120 High fat diet 85

12. Amount of glycogen stored in muscles? Nutrition Amount of glycogen (g/kg muscle) High Carbohydrate diet 40 Mixed diet 20 High fat diet 6 12

13. Muscle Metabolic Systems in Exercise PHOSPHAGEN SYSTEM GLYCOGEN-LACTIC ACID SYSTEM AEROBIC SYSTEM /OXIDATIVE SYSTEM 13

14. Phospagen system 14

15. Glycogen-lactic acid system 15

16. Aerobic system 16

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18. Energy Systems Used in Various Sports  PHOSPHAGEN SYSTEM, ALMOST ENTIRELY 100-meter dash Jumping Weight lifting Diving Football dashes 18

19. GLYCOGEN-LACTIC ACID SYSTEM, MAINLY 400-meter dash 100-meter swim Tennis Soccer 19

20. AEROBIC SYSTEM 10,000-meter skating Cross-country skiing Marathon run (26.2 miles, 42.2 km) Jogging 20

21. Effect of Athletic Training on Muscles and Muscle Performance Muscles that function under no load , even if they are exercised for hours on end, increase little in strength. At the other extreme, muscles that contract at more than 50 per cent maximal force of contraction will develop strength rapidly even if the contractions are performed only a few times each day. M uscle strength increases about 30 per cent during the first 6 to 8 weeks but almost plateaus after that time. Along with this increase in strength is an approximately equal percentage increase in muscle mass, which is called muscle hypertrophy. 21

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23. Muscle hypertrophy (1) increased numbers of myofibrils, proportionate to the degree of hypertrophy ; ( 2) up to 120 per cent increase in mitochondrial enzymes ; ( 3) as much as 60 to 80 per cent increase in the components of the phosphagen metabolic system, including both ATP and phosphocreatine; ( 4) as much as 50 per cent increase in stored glycogen; and ( 5) as much as 75 to 100 per cent increase in stored triglyceride (fat) E fficiency of the oxidative metabolic system increases as much as 45 per cent. 23

24. Fast-Twitch and Slow-Twitch Muscle Fibers B asic differences between the fast-twitch and the slow-twitch fibers are the following: Fast-twitch fibers are about twice as large in diameter. The enzymes that promote rapid release of energy from the phosphagen and glycogen-lactic acid energy systems are two to three times as active in fast-twitch fibers Slow-twitch fibers are mainly organized for endurance , especially for generation of aerobic energy . They have far more mitochondria than the fast-twitch fibers . The number of capillaries is greater in the vicinity of slow-twitch fibers than in the vicinity of fast twitch fibers .\ In summary, fast-twitch fibers can deliver extreme amounts of power for a few seconds to a minute or so . Conversely, slow-twitch fibers provide endurance, delivering prolonged strength of contraction over many minutes to hours. 24

25. Male versus Female athlete A lmost identical basic physiologic principles are applied for both. T here are quantitative differences caused by : a ) BODY SIZE b ) BODY COMPOSITION (MUSCLE MASS) pulmonary ventilation cardiac output muscle strength c) AMOUNT OF TESTOSTERONE d ) AMOUNT OF ESTROGEN M uscle strength per cm2 = 3 to 4 kg/cm2 (same ) 25

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