1) Explain your favorite or most cherished athletic/exercise accomplishment

My most cherished athletic moment was scoring a hat trick in lacrosse during my senior year of high school. A hat trick is when someone scores three goals in one game. Lacrosse is something I have been passionate about ever since starting it in the 7th grade. Out of the three sports I did during high school (basketball, football, and lacrosse) lacrosse was the one that that I always seemed to perform at best. We were playing at home against one of our conference rivals, Christian Brother’s Academy. I was the 3rd leading scorer on my team averaging about 2 goals a game. Our two best players were out with injuries so naturally my team looked to me to step up and score more, which I did end up doing. I scored my first two goals very quickly in the earlier periods and ended up scoring my last goal on a buzzer beating game tieing goal to send my team to overtime. We ended up winning the game in overtime.

2) Why do you think exercise physiology can serve as a paradigm for understanding biology?

Exercise physiology can act as a paradigm for understanding biology because a lot of what we will speak about in class will be based on how our body acts in certain conditions and what pathways or mechanisms affects the way that we act as well. It is important to be able to understand how the body works during exercise or any form of physical activity so you know the ways not to harm yourself and allow your body to perform in the best way it possibly can.

3) How can you use what you learned in previous upper-level courses (BIO, BNG, NS, BioChem, CHM, PHYS, or ?) to contribute to our exercise physiology discussions

I have taken a lot of upper level course that I believe will contribute to my understanding and discussions in this class. I have take organic chemistry and a lot of what we will be discussing is how certain hormones, proteins and other functional groups impact the way our body functions in exercise. I have also taken behavioral neuroscience and neurobiology, and both courses talk in detail about how all of the pathways in our bodies work to send out certain signals which help our body to function on a daily basis. These classes and others will help with my ability to participate in exercise physiology discussions.

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.

1. Powers, Scott K., and Edward T. Howley. Exercise Physiology. 10th ed., McGraw-Hill Education, 2017

The benefits of lactic acid accumulation in muscle cells are constantly debated, with some scientists claiming that the other side’s conclusions are the result of overstating their data. However, there is too much data proving that Lactic acid is disadvantageous to exercise performance. Its accumulation contributes to decreased performance in several ways.

In Lamb’s”Point:Counterpoint: Lactic acid accumulation is an advantage/disadvantage during muscle activity,” which is a response to an original paper, it is argued that elevated lactic acid in the blood causes declined performance, possibly because lactic acid reduces blood pH(1). Since Lactate lowered pH, once blood pH is raised, it has been shown to improve performance. These findings further supports the correlation of lactic acid with declined performance. A possible reason for these results could be due it being reported that disruption of calcium release and reloading of the sarcoplasmic reticulum which may be caused by lactate and H+ ions (1). Lactic acid and fatigue are correlated. Additionally, Lamb states that “there is a positive correlation” between Lactate efflux and performance (1).

It seems apparent that Lactic acid accumulation is disadvantageous, and Lamb appears to not approve of so much debate on the topic when evidence of its negative effects are so abundant. According to Lamb, “In the 1990s, we argued that high lactate and low muscle pH is not the primary cause of fatigue in humans, but it seems to contribute during intense exercise. As it currently stands, evidence is still lacking that this is not the case.”

1. Lamb G.D., Stephenson D.G, Bangsbo J., and Juel C. (2006). Point:Counterpoint: Lactic acid accumulation is an advantage/disadvantage during muscle activity. Journal of Applied Physiology. 100:1410-1414.

My presentation topic is about ACL tears in men vs women. This injury is so common and devastating to an athlete’s career, it can take them out for a whole year and they may never fully recover. My team alone we had 2 ACL tears last year, and have a total of 5 girls who have had the surgery. I want to find out why this occurs so frequently, and if it occurs in males more than females and if there’s a reason why. I can name more girls than guys who have torn them, but I don’t know whether that’s because of the sport they play or because of their gender. People should be interested because it’s an injury anyone can get, not just athletes and can be devastating to recover from. If there’s ways to prevent this from happening, people should want to know about it. Sorry im a slacker and haven’t done research yet on my topic so I haven’t discovered anything yet.

For my project I am going to look at the effects and uses of CBD on athletic performance. CBD, or cannabidiol is a chemical found in cannabis that has been found to reduce pain and anxiety, which is why is has recently surged as a hot topic for professional athletes. Taken as either oil, candy, pills, or other forms, this compound does not produce a high that people associate with marijuana (that’s due to THC). People who undergo rigorous physical training have started using CBD as a non-toxic, non-addictive, natural supplement in order to reduce muscle inflammation and chronic pain. Now researchers are looking into CBD as a possible option for more medically related conditions such as auto immune disorders, neurological conditions, psychiatric illnesses, and more. One article I have read shows that CBD reduces inflammation in rat models of arthritis. This compound works by releasing the neurotransmitter anandamide, the chemical responsible for “runner’s high”. There is lots of controversy in different professional sports organizations whether CBD should be legalized or not. CBD could potentially prevent neuron cell death during a concussion so some players in the NFL believe that it should be legalized. Especially because the compound does not have harmful side effects, it’s becoming more apparent on the market as a positive supplement. I think this topic will be interesting for the class because CBD can be used for so many different conditions not only related to muscle soreness. It’s uses are growing through the research being conducted and I think the class will enjoy learning about how the compound works, how it can be used, and the future market for it as a pain reliever and illness remedy.

For my presentation I am researching the physiological impacts of a Crossfit training regime. I chose this topic because being an athlete, I have heard of/been exposed to many different types of training programs and Crossfit time and time again brings about the most controversy. On one hand, I have been told by strength coaches that Crossfit can be extremely dangerous and harmful and on the other hand, I have spoken to people who consistently do Crossfit and they absolutely swear by it. I don’t know enough about Crossfit to agree with one argument or the other so that’s why I think it’ll be really interesting to research it and see the science behind how it works, what it does for your body, and maybe even how it compares to other workout regimes. I expect that I will find some mixed research in terms of if it is beneficial or not or if it is only beneficial for a certain type of athlete training for something specific. I also expect that I will find that it works better with a specific type of diet. Other people in the class should be interested in this topic because Crossfit is currently a quite popular workout regime so learning about it, especially if the research has positive results, might encourage people to give it a try. On the flip side, if the research shows negative results and class members know people who do Crossfit, they can use the science presented in the presentation to suggest that the person tries a different regime. So far I have only researched what exactly Crossfit entails in effort to gain a solid foundational understanding of the workout prior to researching the science behind it and the bodily costs/benefits of it. I hope to get a start on the more specific research tomorrow or this weekend.

Any suggestions of other directions I can take this in are much appreciated! 🙂

There is an ongoing debate attempting to determine whether lactic acid buildup during exercise is an advantage that improves performance or a disadvantage that results in muscle fatigue occurring sooner. While there is evidence to support both sides of the argument, the data supporting lactic acid accumulation being a disadvantage during muscle activity is more compelling.

A brief intro into what lactate is and why it is produced in the first place: lactate metabolism is necessary to produce the required energy to continue exercising, but its role in the production of hydrogen ions depresses muscle function. So while the lactate is being produced to satisfy high energy demands, it must be cleared from the muscles and sent to the liver to be metabolized (or sent to the muscles to be used as an energy source) if the activity is to continue. In general, adrenaline causes a decrease in the clearance of lactate and fast twitch fibers produce the most lactate [1].

The first crucial data supporting lactic acid’s role in muscle fatigue is that when the lactate concentration of the blood is elevated, there is a reduction in overall performance. These studies take into account the potential fatigue factor by exercising one part of the body to increase the lactate levels, and then while the blood had these increased levels, they exercise another part of the body until fatigue. It has been done over and over again, with all the studies producing the same results: increased blood lactate levels promote muscle fatigue. The performance reduction was associated with a lower release of lactate, a lower muscle pH, and a greater potassium release. These factors work together to result in a potassium buildup in the muscle interstitium, which leads to fatigue [2].

Another study that has been done to test the effects of lactate on muscle fatigue involved incubating the muscle in lactic acid. These studies have found that when the muscles are incubated in lactic acid, force development is reduced and fatigue is achieved faster. The studies also found that lactate mostly affects the function of the muscle membrane and that the effect of lactate can be linked back to the pH-induced changes, such as the potassium balance [2].

Lactate does not just affect the pH balance and potassium concentrations. It also has been found to affect the intracellular calcium, which is responsible for muscle activation. The lactate affects the sarcoplasmic reticulum’s calcium release channels, affecting calcium’s ability to bind to the troponin, providing a binding site on the actin filament for the myosin head to bind to, causing a muscle contraction. Since this process is inhibited, muscle contraction is limited [2].

Lactic acid is not necessarily what is causing the fatigue. Lactic acid is dissociated into lactate anions and hydrogen ions under normal internal body conditions, so it is the lactate anions and hydrogen ions that are accumulating in the muscle, not ‘lactic acid’. It is believed that the hydrogen ion accumulation is what truly influences muscle fatigue, as opposed to the lactate anions. Studies support the earlier claims that the decline in exercise performance is due to the decrease in sarcoplasmic reticulum function, increase in hydrogen ions, and inhibiting the calcium, which inhibits the myofibrillar ATPase thereby inhibiting the maximal shortening velocity [1].

When these factors work together (the potassium accumulation, low pH, the calcium release channels), muscle fatigue is inevitable. So while lactate may not directly cause fatigue, it induces enough changes within the normal pathways to affect the process and cause fatigue.

(FYI: Based on the articles I found during my research, I am more on the lactate is advantageous bandwagon.)

References:

[1] Aldeam Facey, Rachael Irving, and Lowell Dilworth, “Overview of Lactate Metabolismand the Implications for Athletes.” American Journal of Sports Science and Medicine 1, no. 3 (2013): 42-46.

[2] Point:Counterpoint, “Lactic acid accumulation is an advantage/disadvantage during muscle activity.” Journal of Applied Physiology, 100 (2006): 1410-1414.

Think back to when you first learned about lactic acid (now known to exist in the body as lactate). The context was probably not a good one. In fact, it was probably negative because it meant you couldn’t run as fast as you wanted and that you would lose to your siblings in tag.

The fact of the matter is that lactate prevented you from performing as well as you would have liked. Lactate accumulation is without a doubt disadvantageous for the human body and to argue it as advantageous is to simply ignore a fundamental fact of its existence.

Fatigue commonly occurs during intense exercise and can be induced by factors such as oxidative stress, dehydration and lactic acid accumulation in the muscles.1 Lactic acid accumulation in the muscles can cause intracellular pH to decrease by as much as 0.5 pH units. This acidosis stimulates fatigue by slowing down energy metabolism in the human body (1).

Such fatigue is not confined to the muscle that is exercising. Elevated lactic acid in the blood causes declined performance, even when you go from arm to leg exercise (2). Raising blood pH after it has been reduced by lactic acid has been shown to improve performance and this further supports the correlation of lactic acid with declined performance (2). The reason may be due to the disruption of calcium release and reloading of the sarcoplasmic reticulum which may be caused by lactate and H+ ions (2).

The method of lactic acid incubation, which has been used by some to suggest the benefits of lactate, does not accurately model what takes place during exercise. One deficit is that such experiments model a decreased transmembrane pH gradient when in vivo there is an increase in this gradient in skeletal muscle cells. (2)

Lactic acid and fatigue are correlated. Additionally, getting rid of lactic acid (efflux) is associated with greater performance and the ability of the body to perform efflux can be ascertained with training (2). If lactic acid goes hand in hand with fatigue, getting rid of it improves performance, and the body’s ability to efflux can be improved with training, it seems reasonable to conclude that lactic acid is disadvantageous to the body. If it were advantageous then getting rid of it would cause a decline in performance, not an improvement.

A study done on patients with chronic fatigue syndrome (CFS) showed that these individuals presented with an increase in aerobic Gram positive intestinal bacteria (3). What was interesting was that these bacteria produce D- and L-lactic acids from glucose metabolism. D-lactic acid is thus found elevated in the serum and is associated with cognitive dysfunction and neurological impairment (3). While this study is not directly related to exercise, it shows that chronic lactic acid accumulation can result in chronic fatigue syndrome. Lactic acid accumulation is disadvantageous for these individuals and similarly for healthy, exercising individuals.

References

1. Halim H.H., Dek M.S.P., Hamid A.A., and Jaafar A.H. (2017). Fatigue onset through oxidative stress, dehydration and lactic acid accumulation and its in vivo study using experimental animals. Journal of Advanced Review on Scientific Research. 35(1):1-12.
2. Lamb G.D., Stephenson D.G, Bangsbo J., and Juel C. (2006). Point:Counterpoint: Lactic acid accumulation is an advantage/disadvantage during muscle activity. Journal of Applied Physiology. 100:1410-1414.
3. Sheedy J.R., Wettenhall R.E.H., Scanlon D., Gooley P.R., Lewis D.P., McGregor N., Stapleton D.I., Butt H.L., and Meirleir K.L. (2009). Increased D-Lactic Acid Intestinal Bacteria in Patients with Chronic Fatigue Syndrome. In Vivo. 23(4):621-628.

There is a lot of debate especially since the early 2000s on whether or not lactate accumulation is an advantage or disadvantage to skeletal muscles. Lactate can effect the release of Ca+ in a muscle in a negative way. Lactate can cause an impairment on the release of Ca+ release channels on the sarcoplasmic reticulum [1]. This is a problem because Ca+ plays a major role in muscle contraction. If Ca+ channels cannot release calcium ions properly it can effect muscle contraction. When you are working out and develop a build up of lactate, your muscles do not contract as well and can lead to a fatigued feeling. This build up of lactate and H+ ions can decline the force your muscles can exert [2]. An experiment was performed to test if lactate build up is related to muscle fatigue. Subjects had to perform an arm workout and follow it with a leg workout [1]. When doing the leg exercise after the arm workout there was evidence of a shorter time until muscle fatigue set in compared to subjects who did not perform an arm workout prior [1]. There was a lower pH and lactate release from the leg exercise, meaning the muscles have been fatigued faster. The lower pH in muscles is shown to decrease overall muscle performance [2]. When muscles can’t perform at their best they start to tire and result in eventual fatigue. The lower pH and decrease in Ca+ release can cause muscles to fatigue faster than those that have higher pH levels and normal Ca+ release.

[1] Burnley, Mark, et al. “Lactic Acid Accumulation Is an Advantage/Disadvantage during Muscle Activity.” Journal of Applied Physiology, vol. 101, no. 2, 2006, pp. 683–683.

[2] Cairns, Simeon P. “Lactic Acid and Exercise Performance.” Sports Medicine, vol. 36, no. 4, 2006, pp. 279–291.

The idea that lactic acid buildup causes muscle fatigue is preposterous.  Lactic acid buildup is not only irresponsible for the fatigue and decreased muscular performance, but rather other sources of fatigue can be discovered in different muscle groups.  During performance it can be observed that the excitation-contraction coupling steps are impaired when under high stress.  One example of this can be observed in the transverse-tubular system has a buildup of potassium ions.  This system is in the direct vicinity of muscle-fibers, so a buildup of ions during exercise would impair the muscle fibers’ abilities to keep sodium ion equilibrium.  A buildup of inactive sodium inside the fibers leads to the inactivation of action potentials, and in turn a slower functioning muscle fiber. 

Another explanation for the fatigue and limited performance of muscles can be observed in the accumulation of metabolites coupled with a limited level of substrate.  When muscle fibers (especially fast-twitch muscle fibers) exert energy, they utilize a wide variety of substrates to fuel themselves.  In many cases, a great increase in energy use in fast-twitch fibers can cause  ATP in the tissues to decrease to extremely low levels, and subsequently a decrease in the glycogen stores as the cells try to keep up with the rate of ATP use.  

Since lactate does not affect the excitation-coupling steps it can be determined that it is not responsible for muscle fatigue.  The higher level of hydrogen ions do not lead to any change in the pathway, or a greater production of metabolites that would lead to muscle fatigue.  It could even be argued that the lower pH brought on with higher lactate concentrations actually aid the muscles in fighting fatigue, as chloride ions are retained better and action potentials can be maintained when the cell is functioning at a high rate.  In the absence of lactate it has been observed that the action potentials are inhibited faster, and this is directly related to muscle fatigue and performance.  

The point-counter point argument has been explored further in other articles as well.  A study found in the American Physiological Society determined that the cause of muscle fatigue during high-intensity exercises was not actually lactic acid buildup, but rather a buildup of phosphate ions due to the breakdown of creatine phosphates.  During high-intensity exercises our bodies rely on anaerobic sources of energy, so increased lactate levels should be irrelevant to the function and fatigue of muscle cells.  This falls in line with the claim made in the point-counterpoint article, and further goes to show why lactic acid buildup does not affect the function or fatigue of muscular tissues. 

Works Cited

Westerblad, Håken, et al. “Muscle Fatigue: Lactic Acid or Inorganic Phosphate the Major Cause?” Physiology, American Physiological Society, 1 Feb. 2002, www.physiology.org/doi/full/10.1152/physiologyonline.2002.17.1.17.