13fitness - Physical Fitness Name Objectives: To gain an...

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Physical Fitness Biology 100 - Concepts of Biology 13.1 Name Instructor Lab Section____________ hat exactly do we mean when we say a person is physically fit? You'll recall that many of the activities required to sustain life (e.g. active transport, growth, movement) require energy. This energy is produced by the breakdown of food (carbohydrates, lipids, and proteins) through the process of respiration. Also recall that the most efficient release of energy occurs in the presence of oxygen ( aerobic respiration ). However, unlike food, oxygen cannot be stored in the body. It must be constantly taken into the body and transported to all cells to sustain their activities. W Muscle cells used to produce movement in a physical activity demand large amounts of energy. As the need for energy increases with increased exertion, so does the need for oxygen in the muscle tissue. Often during vigorous physical activity more oxygen is required by the muscles than the body can supply. In such situations, the supply of oxygen is insufficient to produce all the energy needed by the muscles. Instead of just giving up, the muscles release energy from food molecules without oxygen, or anaerobically . However, this conversion is not very efficient, and soon the inadequate supply of energy along with the accumulation of anaerobic by-products (the primary one being lactic acid) results in fatigue. The more vigorous and prolonged the activity, the greater is the oxygen debt ” that develops, and the greater the stress on the heart, lungs, and muscles. Once the activity is over, the individual will continue to breathe rapidly for a time to provide the body with the oxygen that he or she was unable to acquire while active. The oxygen is used to convert the accumulated lactic acid into water and carbon dioxide. In this way one makes up or "pays back" the oxygen debt incurred during exercise. Regular participation in physical activities results in changes in the heart, blood vessels, blood, and lungs, that are geared toward more efficiently supplying the body with oxygen (aerobic conditioning). Therefore, when we speak of physical fitness, we are considering (1) how efficiently the lungs (respiratory system) can take oxygen into the body, (2) how efficiently the heart, blood, and blood vessels (cardiovascular system) can transport it to the muscles during times of physical stress, and (3) how rapidly the muscles can utilize the oxygen and food to release energy for contraction. The following tests are designed to measure your physical fitness or aerobic conditioning. Keep in mind the above idea of physical fitness and try to relate the design of each test to that concept. RESPIRATORY CONDITION
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This note was uploaded on 12/01/2009 for the course BIO BIO130 taught by Professor Goralka during the Spring '09 term at Diablo Valley College.

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13fitness - Physical Fitness Name Objectives: To gain an...

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