Personally, my favorite topics this term was when we learned about the various muscles fibers in our body as well as the mechanisms needed for contractions to occur. Prior to this course I did not know the details of each fiber type (Type I, Type IIa/x). Learning about various fiber types in depth was very informative not only for class, but also real world applications. Understanding the details of how myosin and actin are able to work together and generate force was interesting as well. These are things that occur in our body all the time without us putting much thought or effort into it. Learning which muscles types are advantageous/disadvantageous for specific activities and knowing that it is possible for an individual to change their fiber types based upon their needs was neat as well. Overall, I really enjoyed the class and learned a lot these past ten weeks.
I found an article that talks about a possible breakthrough in diagnosing CTE in a living person. Chronic traumatic encephalopathy (CTE) is a degenerative brain disease that is often caused by persistent head trauma. This disease usually occurs among athletes that play contact sports, such as football. As of right now, the only way to diagnose CTE is after death through a brain autopsy. However, a new study has identified a possible biomarker in the cerebrospinal fluid which could allow doctors to diagnose CTE in a living person. According to the study, the biomarker is a protein called tau. The study consisted of 22 men who were professional athletes and have experienced multiple concussions. The study also included 12 people with Alzheimer’s disease and five healthy individuals to serve as the control group. The researchers found elevated levels of tau in the cerebrospinal fluid for more than half of the athletes (12 out of the 22). The 12 athletes with elevated tau had higher levels than the healthy individuals, but lower levels than the participants with Alzheimers. Researchers also found that the athletes with elevated levels of tau scored lower on executive functioning tests than the athletes with normal tau levels. These tests assessed memory, attention, organizational and planning skills. Brain scans also showed that individuals with elevated tau show differences in white matter of the brain which are also seen during autopsies in people with CTE. Dr. Jamie Ullman, director of neurotrauma at North Shore University Hospital, believes that this discovery of a possible CTE biomarker is encouraging. However, she emphasized that additional studies with larger sample sizes and inclusive of both genders must be conducted. Unfortunately, there’s no way to definitively diagnose CTE in a living person as of right now, however, with more promising research we may be able to in the near future.
For my presentation, I want to research how high altitudes can affect an athlete’s performance. Ever since Peyton Manning signed with the Denver Broncos I constantly heard how the air is thinner in Denver and how players were more fatigued when playing their. For example, Coors Field in Denver, where the Colorado Rockies play, has an altitude of nearly 5200 ft above sea level. The stadium with the second highest altitude is Chase Field in Phoenix with an altitude of less than 1100 ft above sea level. To me, that’s a staggering difference between the stadiums with the two highest elevations. Interestingly, this current NBA season, the Denver Nuggets had the best home record in the NBA despite not being a top 3 team in terms of talent. So I always wondered how much of a home-field advantage was the altitude? How do the home players train/practice to overcome it? From our textbook, we learned that endurance exercise performed at higher altitudes can impair performance and is associated with increased levels of stress hormones that could reduce immune function. Not only can high altitudes hinder performance, but can also lead to an increased risk of infection due to a combination of stresses, such as low arterial oxygen levels, high altitude related sleep disorders, and acute mountain sickness (1). Now, clearly, this didn’t seem to affect Peyton, who is the best QB of all time, as he went on to throw the most touchdowns in a single season, win his fifth MVP award, and another Super Bowl during his twilight years in Denver. However, I am sure the altitude affects virtually every player, especially the visiting team.
- Powers, Scott K., and Edward T. Howley. Exercise Physiology. 10th ed., McGraw-Hill Education, 2017
It was not until recently that lactic acid was viewed upon as a potential source of energy, and, in fact, is not the reason for muscle fatigue. There are several different types of muscle fatigue, the varying differences are dependent on the type of physical activity as well as the muscle fiber type. The first type of fatigue is due to a buildup of K+ in the transverse-tubular system and in the adjacent muscle fibers. This buildup depolarizes the fiber and hinders Na+ channels from recovering. This type of fatigue can be significant since the concentration of K+ during intense activities can reach high levels. Another type of muscle fatigue is known as “metabolic fatigue.” This type of fatigue emerges due to the indirect or direct effects of metabolite buildup and decrease in substrates within muscle fibers. In fast twitch muscle fibers, cellular ATP drops to extremely low levels and can cause a reduction in the release of Ca2+. This fatigue can also occur due to the direct or indirect effects of glycogen depletion. Decreasing the pH of muscle fibers from 7.1 to less than 6.7 does not expedite or cause onset fatigue, instead, it slows its onset. In fact, decreasing intracellular pH to 6.7 negates the inhibitory effects of an increase in extracellular potassium concentration.
According to a paper in the American Journal of Physiology, UC Berkeley researchers concluded from their lab results that muscle cells use carbohydrates anaerobically for energy, which produces lactase as a byproduct, and then uses the lactate alongside oxygen to generate more energy. The first method is called the “glycolytic pathway”, and is the main pathway during normal exercise. During this method, lactate trickles out of the muscle cells to be used elsewhere. However, during intense workouts, the rapidly accumulating lactate is oxidatively removed to create more energy.
- One of my favorite athletic moments was during the spring of my senior year of high school. A lot of my friends and I decided to play rugby that spring even though none of us had ever played it before and it would probably be the last time all of us would be on the same sports team together. It was the first time rugby had been offered as a sport at our school so it would be pretty cool to be a part of the inaugural season. It’s basically football without the pads, and it was pretty damn fun. Running through people and tackling without pads and a helmet seemed odd at first, but we eventually got the hang of it. Overall we had a pretty good inaugural season going 4-1. But to me that spring was more than just playing rugby, it was about being on the same competitive field as your friends one last time.
- Understanding exercise physiology is important to know since it affects our day to day lives. It’s crucial to understand how the body responds to varying situations such as during a workout, running, or even at different climates and what it does in order to maintain homeostasis. It’s also critical to know how different parts of the body work together in order to keep ourselves functioning properly. That is why exercise physiology is paramount in order to understand biology.
- I think a lot of the concepts from behavioral neuroscience and evolutionary biology could be useful for exercise physiology. Understanding how the nervous system responds to varying stimuli throughout the body should be useful for understanding how the body maintains homeostasis. Also understanding how/why certain traits are more beneficial than others could also help contribute to exercise physiology.