o Type I Fire and fatigue SLOW, not a lot of force, can contract over and over again Low intensity tasks (ex: walking) Lot of mitochondria Red (“dark meat”) As energy intensity goes up, we begin to recruit Type IIA fibers in addition to Type I o Type IIA Fast oxidative glycolytic Moderate amount of mitochondria Red Jogging / faster paced running Fatigues at moderate speed When this can’t do job either, we recruit Type IIB fibers o Type IIB Fast-twitch glycolytic fibers Weight training sessions Fatigue very quickly Few mitochondria White (“white meat”) What is the role of the cardiovascular system with regards to muscle contraction?
o Type I (force required) (aerobic – oxidative) (walking) (oxidation of fat) o Type IIA (more force required) (jogging) (oxidation of glucose) (lactic acid production) o Type IIB (most force required)(anaerobic - glycolytic) (sprinting) (glycolysis) (ATP PC) What is VO2? o VO2 (volume of oxygen consumed) represents the amount of oxygen consumed and utilized for this energy production o Determines exercise intensity VO2 max is most amount someone can use – higher VO2 max, higher fitness level – more oxygen they can utilize, more they can do Explain the difference between acute and chronic responses. o Acute responses are only present during exercise where as chronic responses last for a longer time. What are the acute and chronic adaptations that occur in the cardiovascular system with exercise? o Acute response to aerobic exercise To increase delivery of oxygen to working muscles, cardiac output increases via increased HR and SV in response to work (oxygen consumption) Heart rate increases, blood pressure increases (diastolic remains stable), stroke volume and cardiac output increases, blood flow/distribution (muscles in legs open), oxygen consumption increases, ventilation rate and volume increases o Chronic Adaptations The increased blood flow back to heart causes and eccentric hypertrophy of the heart chamber increasing its capacity Every time we exercise, blood shoots back to heart chamber gets bigger and adapts to hold more blood able to pump out more blood when it beats heart rate goes down a little Skeletal muscle improves at extracting oxygen and using oxygen through numerous adaptations, such as: increased capillary density, increased mitochondria density, increased myoglobin, and increased aerobic enzymes Muscle becomes better equipped to utilize fuel sources (carbs and fat) to produce ATP through aerobic metabolism Increased oxidation of fats, increased stores of triglycerides, increased stores of glycogen, etc.
Describe the changes that occur to skeletal muscle with resistance training. Muscle fiber recruitment increases Muscle fiber size increases (hypertrophy) Mitochondrial volume decreases Capillary volume may decrease Anaerobic enzyme activity increases ATP-CP-Glycogen stores increase Growth hormone and testosterone levels increase
- Spring '14
- physical activity