1) Describe the stretch shortening cycle and how it relates to exercise in 250 words.
2) Give an example of a sport athlete that utilizes each of the three major energy pathways. How long does the body utilize each pathway as its main energy source? in 250 words
Expert Solution Preview
Introduction: In this response, we will be discussing two topics related to exercise physiology. The first topic is the stretch-shortening cycle and its relevance to exercise. The second topic is the three major energy pathways utilized during physical activity and an example of a sport athlete who utilizes each pathway.
1) The stretch-shortening cycle refers to the combination of a muscle stretch followed immediately by a contraction, known as a plyometric movement. The stretch reflex and the elastic energy stored in the muscle are both utilized during this cycle to increase power output during a movement. During the stretch phase, the proprioceptors in the muscle spindles are activated and send a signal to the spinal cord, resulting in the muscle’s contraction. Following the contraction, the elastic energy stored in the muscle is utilized to further increase the muscle’s power output. The stretch-shortening cycle is relevant to exercise as it is commonly utilized in plyometric training to improve power, agility, and overall athletic performance. Examples of exercises that utilize this cycle include jump squats, depth jumps, and bounds.
2) The three major energy pathways utilized during physical activity include the phosphagen system, glycolysis, and aerobic metabolism. The phosphagen system is the primary energy source for short, powerful movements lasting up to 10 seconds. Examples of athletes who utilize this system include sprinters, weightlifters, and jumpers. Glycolysis is the primary energy source for moderate to high-intensity exercise lasting up to 2-3 minutes. Athletes in sports such as hockey, basketball, and soccer utilize this system. Finally, aerobic metabolism is the primary energy source for low-intensity exercise lasting longer than 3 minutes. Endurance athletes such as marathon runners, cyclists, and triathletes primarily utilize this system. The duration of time that the body utilizes each pathway as its primary energy source is dependent upon several factors, including exercise intensity, duration, and an individual’s fitness level.
