ATHLETE x SCIENCE
ATHLETE x SCIENCE
The benefits of CrossFit are under-researched in a long-term capacity, however, a number of studies have determined the potential benefits of this type of high-intensity functional power training on aerobic capacity and body composition. High-intensity interval training is desirable to many individuals looking to improve fitness levels with minimal time commitment to training. Typically, these types of workouts take a very short amount of time, averaging between 5 and 20 minutes, and reap maximal caloric burn due to the continuous nature of the workload, relative intensity, and minimal rest periods. In some workouts, participants target achieving as many rounds or reps as possible before the allotted time is up, whereas other workouts request the best time to completion of a given set of exercise rounds. A combination of power and Olympic lifts, cardio activity, gymnastics and other body weight movements, is used to stimulate positive adaptation of maximum aerobic capacity and body composition.
Smith, Sommer, Starkoff, & Devor (2013) prove such an example in their study on the effects of crossfit-based high-intensity power training (HIPT) on body composition and aerobic fitness. The 10-week HIPT program consisted of both traditional power and Olympic lifts including: squat, deadlift, clean, snatch, and overhead press, however performed in a non-traditional fashion of completing the designated number of repetitions as quickly as possible (Smith et al., 2013). After HIPT training, body fat reduced by 3.7% across all individuals, in both male and female categories (Smith et al., 2013). Oxygen consumption relative to body weight increased in all participants, resulting in a 13.6% and 11.8% improvement in VO2 max for men and women, respectively (Smith et al., 2013). This was independent of the changes in body mass, which is often attributed to the improvements of oxygen capacity (Smith et al., 2013).
CROSSFIT vs. NSCA
In this study, 16% of participants did not complete the program or return for follow-up testing (Smith et al., 2013). Although this limitation was expressed in a paragraph noting the potential for injury risk when partaking in this type of exercise, it was never claimed that the reason for the 16% failure was injury or overuse. This makes the claims staked by the defendant (CrossFit, Inc.) in the case of CrossFit vs. the National Strength and Conditioning Association (NSCA) completely invalid. This study, which is published in favor of CrossFit-style HIPT in the NSCA’s primary educational resource, the Journal of Strength and Conditioning Research, states as follows (Smith et al., 2013):
With more than 13,000 CrossFit gyms (or “boxes”) established throughout the country, intense scrutiny should be placed on this company’s mission and training principles in order to decipher whether or not this is a efficacious and safe form of athletic conditioning. Any emerging form of exercise or dieting should be challenged on the basis of evidence-based practice in order to properly validate and promote programs which are both safe and effective for the long-term health and well-being of all participants, with long-term being the key word here.
In a review of the pros and cons of extreme conditioning programs such as CrossFit, a 2013 survey was referenced in which CrossFit participants were asked to disclose any injuries that had prevented them from working, training, or competing over the past 19 months (Knapik, 2015). The survey 132 respondents averaged 5.3 hours/week during this time, and 74% claimed to have sustained an injury during that time, 7% having an injury which required surgery (Knapik, 2015). The most common injuries were distributed to the shoulder (32%), spine (28%), and arm (20%) (Knapik, 2015).
Other cases have been reported for exertional rhabdoymyolysis and carotid artery dissection (CAD) in association with CrossFit activity (Knapik, 2015). The four cases of CAD were attributed to lifting significantly more weight than previously done (20% more) and/or to performing exercise which involved rapid, twisting movements (Knapik, 2015). CAD can result in a partial blockage of the carotid artery, a partial tear in the vessel wall resulting in a hematoma, or a total rupture and subsequent aneurysm, with the goal of treatment being the reduction of neurologic deficits and the stability of blood flow (Knapik, 2015). Repetitive eccentric contractions produce the muscle damage that leads to exertional rhabdomyolysis (Su, 2008). Extreme muscle breakdown results in leakage of muscle enzymes, including creatine kinase, lactate dehydrogenase, and myoglobin, and electrolytes such as potassium. When the level of myoglobin in the blood exceeds 3mg/L, it spills into the urine (termed myoglobinuria) and produces a tea/cola coloration (Su, 2008). Myoglobin damages renal tubules, which can lead to tubular necrosis, and if renal blood flow is further limited by a high exertion level and dehydration, the kidneys are less capable of clearing the muscle breakdown products which can lead to fatal complications (Su, 2008). The very nature of CrossFit workouts brings an increased likelihood for these injuries of ‘overexertion’ to occur.
Weisenthal et al. (2014), conducted a similar survey via the main CrossFit website reaching 386 participants meeting the inclusion criteria for CrossFit participation. Data from the study concluded that injury rate over the prior 6 months was determined to be 19.4% having had at least one injury across all individuals, with males being injured more frequently than females. The shoulder was the most commonly injured body part during gymnastic movements, while the lower back was most often from power lifting movements, without have had prior discomfort in that area (Weisenthal et al., 2014).
High-risk should not be confused with “ineffective,” since most all exercises provide benefit in some manner; though, the aim of exercise should always be to maximize benefits and minimize risks (Mullins, 2015). Two very high risk exercises commonly performed in a CrossFit setting are unassisted pistol squats and kipping pullups, both of which are rarely able to be performed with proper execution (Mullins, 2015). In the pistol squat, the lordodic curve of the lumbar spine should be maintained, the knee should track over the toes with virtually no mediolateral shift, and the heel should remain in contact with the ground (Mullins, 2015). Rounding of the back is a compensatory mechanism used to achieve depth in the pistol squat and places unnecessary strain on the lower back (Mullins, 2015). Kipping pullups result in lumbar hyperextension, unlike traditional pullups which allow the spine to stay in neutral (Mullins, 2015). Hyperextension of the spine has long been contraindicated by medical professionals due to the high potential for injuring the spinal discs, nerves and joints (Mullins, 2015).
The incidence of injury was reported to be much less when an individual was working with a trainer, and the lower female incidence rate can be attributed to their likelihood of seeking a coach prior to training (Weisenthal et al., 2014). With nearly a 20% injury rate, however, the jury is still out on whether or the risk-benefit ratio is in an athlete’s favor. Similar rates of injury are seen in the sport of gymnastics and on the Power/Olympic lifting scenes.
Assigning high volume repetitions and speed to technically-demanding exercises opposes USA Weightlifting’s recommendation to keep “repetitions to three or less on technical exercises [Olympic movements] and five or less for strength exercises (e.g. squats), and never continue repetitions if form is breaking down” (Mullins, 2015). The entire foundation of CrossFit is based around a total-body fatigue, forced-adaptation model, risking form break-down and injury with every repetition that passes. The NSCA aligns with the USAW philosophy, and stressed the importance of exercise order for maximal adaptation gains and the insurance of safety (Mullins, 2015):
Some CrossFit facilities are run by well-educated, exercise science professionals who make an effort to ensure all participants are practicing safe technique and sound progressions with individualized program design. One such individual is Dr. Mike Young, Director of Performance and Research with Athletic Lab in Cary, NC. When incorporating CrossFit programming into his Sports Performance and Athletic Development facility, he takes the following approach:
CrossFit v. National Strength and Conditioning Association, No. 3:14-cv-01191-JLS-KSC (S.D. Cal. May 12, 2014).
Knapik, J. J. (2015). Extreme Conditioning Programs: Potential Benefits and Potential Risks. Journal Of Special Operations Medicine: A Peer Reviewed Journal For SOF Medical Professionals, 15(3), 108-113.
Mullins, N. (2015). CrossFit: Remember What You Have Learned; Apply What You Know. Journal Of Exercise Physiology Online, 18(6), 32-44.
National Strength and Conditioning Association. (n.d.). NSCA update to CrossFit Inc claims and allegations.
Smith, M. M., Sommer, A. J., Starkoff, B. E., & Devor, S. T. (2013). Crossfit-based high-intensity power training improves maximal aerobic fitness and body composition. Journal of Strength and Conditioning Research, 27(11), 3159- 3172.
Su, J. (2008). Exertional rhabdomyolysis. Athletic Therapy Today, 13(5), 20-22.
Weisenthal, B. M., Beck, C. A., Maloney, M. D., DeHaven, K. E., & Giordano, B. D. (2014). Injury Rate and Patterns Among CrossFit Athletes. Orthopaedic Journal Of Sports Medicine, 2(4), 2325967114531177.
Running economy is not an innate ability but must be developed through coordination skills and then refined by more advanced training. Over time, a functional coordination pattern replaces the generalized one, the number of muscles activated decreases to only the necessities, and energy cost reduces. Beginner endurance athletes initially have a steep adaptation curve as they acquire general fitness just by putting in miles, often regardless of how those miles are structured. When a non-athlete first begins a training program, significant neuromuscular adaptations occur to create basic coordination which lays the foundation for biomechanical efficiency (running economy).
Running economy is defined as “the steady-state oxygen consumption at a given running velocity.” (Bonnacci, et al. 2009). In other words, better running economy equates to a more efficient use and recycling of oxygen during a workout. There is a direct correlation between running economy and performance; improving economy through training has a positive effect on performance. To develop the most efficient mechanics possible, we must create optimal muscle recruitment patterns. This conserves the greatest amount of energy used per stride. Well-trained, advanced runners have extremely refined muscle recruitment patterns compared to novice athletes. Positive adaptations to training are a function of a learned response where the body acquires specific movement patterns linked with ideal task completion.
As a runner masters the skill in practice through repetition, they experience an observable decrease in muscle activation, recruitment of synergists, and variation in movement. In other words, even the most complex skill will form the simplest, most efficient muscle activation pattern.
To learn about training adaptation in the realm of triathlon, read more at https://simplifaster.com/articles/adaptations-to-training-for-runners-and-triathletes/
Intense physical exercise creates an inflammatory stress reaction within the body, which can produce both adaptive and maladaptive physiologic responses. It has be undetermined by prior research, whether or not antioxidant supplementation during training may encourage the adaptive state (Slattery et al., 2015). If reactive oxygen species accumulate in excess, athletes may experience the symptoms of overtraining such as chronic fatigue. Uncontrolled oxidation of molecules can result in lipid, protein, and DNA damage, which results in diminished cellular function (Slattery et al., 2015). DNA damage is caused by an alteration in the pathways of transcription and can interfere with the positive outcomes generated for DNA adaptation to exercise-induced stress (Slattery et al., 2015). Disturbances in homeostatic balance can affect the function of other systems as well, such as metabolic, neuroendocrinologic, oxidative, physiological, psychological, and immunologic. Both antioxidants and branched-chain amino acids can help combat the effects of exercise induced oxidative stress.
Antioxidants and Inflammation
Antioxidants work by converting reactive oxygen species to less reactive molecules to eliminate additional stress. There is an endogenous mechanism for which combats the build-up of oxidative species during exercise. A low dietary intake of antioxidants can result in a decreased ability to utilize this endogenous reduction mechanism (Slattery et al., 2015). An excessive intake of antioxidants can cause an opposing reaction, suppressing the redox signaling process at a cellular level, hindering the beneficial effects of exercise at this level (Slattery et al., 2015). Consequentially, the exogenous antioxidant intake can prevent adaptive exercise processes from occurring during and after exercise. One study showed that administering 1,000IU of Vitamin C and 400IU of Vitamin E inhibits training-induced increases in skeletal muscle protein (Slattery et al., 2015).
Antioxidants have been shown to improve the exercise-induced inflammatory state that occurs as a result of musculoskeletal insult. Supplements such as Co-enzyme Q10, tart cherry juice and pomegranate juice can accelerate recovery by reducing inflammatory damage (Slattery et al., 2015). Most studies consist of an acute bout of exercise to induce drastic muscular damage for the purpose of testing, and then supplementation is compared against a control for immediate study (Slattery et al., 2015). Prolonged supplementation of these antioxidants can potentially have the same negative redox effects as mentioned above, however there are no long-term studies on this in particular (Slattery et al., 2015). It seems as though there is an optimal dosage of antioxidants that can create an adaptive, anabolic, regenerative, and enhanced state of performance and recovery, as seen in the figure below. Further research needs to be done to solidify that reference range for the various antioxidant supplements available to athletes.
Continue reading the full article and other sport science research at https://simplifaster.com/articles/supplements-combat-exercise-induced-inflammation-oxidative-stress/
There is a fine line between a healthy habit and an addictive obsession. The phrase ‘healthy obsession’ is really an oxymoron, since obsession is arguably a pathological, diseased state of the mind, and therefore not healthy. Definitions for obsession range from ‘compelling motivation’ to ‘compulsive preoccupation’. However you want to label it, obsession relates to an altered state of consciousness in which the need or compulsion to do a certain act overpowers all else, becoming a priority over all other needs and obligations in a person’s life.
When exercise becomes the obsession, the risk of dependence is lurking like an obsequious servant. You may have heard of the so called, ‘runner’s high,’ which presents as a euphoria from the natural opioid-like chemicals, called endorphins, released in the brain during exercise (Freimuth, Moniz, & Kim, 2011). Another theory proposed to explain the euphoric mechanism has to do with catecholamine release, which directly improves mood, attention, movement, and the body’s endocrine/cardiovascular responses to stress (Freimuth et al., 2011).
For a habitual runner, the “high” comes further and further into the run as tolerance is built. The desire to reach euphoria creates an internal drive and self-motivating factor that increases pain tolerance in order achieve this elevated state with every workout. The reward is greater with every level breached and a dependency on the feeling of euphoria is created, much like a drug addiction. Addiction is most likely to occur when the behavior is the primary or sole means of coping with internal distress (Freimuth et al., 2011), or at least the only successful outlet. Dependency requires that the person commit to the exercise no matter the cost, through injury and illness alike.
According to Modolo et al. (2011), compulsive athletes report four components of addiction: 1) feeling euphoria, 2) the need to increase the dose of exercise to obtain feelings of well-being (tolerance), 3) difficulties in the performance of professional or social activities (rearrangement of priorities) and 4) symptoms of the absence or need, including depression, irritability, and anxiety, when unable to engage in the activity (withdrawal). This study also found a direct relationship between the intensity of exercise and the severity of withdrawal symptoms (Modolo et al., 2011). The time spent preparing for, engaging in, and recovering from workouts and the continuance despite exacerbating physical, psychological, and/or interpersonal problems are two more signs that a healthy habit has turned into a neurotic addiction (Freimuth et al., 2011). More negative characteristics include low self-esteem, the use of exercise as management or manipulation of psychological states, increasing body dissatisfaction, and chronic vulnerability to overtraining injuries (Gapin, Etnier, & Tucker, 2009).
The physical manifestations of exercise dependence have been most documented in distance runners; persistent soft tissue injuries (sprains and strains), stress fractures, pressure sores, gastrointestinal blood loss and iron-deficiency anemia just name a few of the damaging side effects observed in this population (DeCoverly Veale, 1987).
From a genetic standpoint, asymmetry in the brain has been correlated to negative emotions and psychological dysfunction. One study in particular found a relationship between frontal lobe brain asymmetry and exercise addiction, implying that exercise directly activates and alters the part of the frontal lobe responsible for affect and mood, thereby improving negative emotions (Gapin, Etnier, & Tucker, 2009). There are often feelings of guilt associated with the absence of or inability to exercise for even one day, and dieting to improve performance is common (DeCoverly Veale, 1987). It should be noted that there is a strong risk and link between eating disorders and excessive exercise, since it is often the primary means of weight loss (DeCoverly Veale, 1987). It is important to distinguish one from the other, usually by analyzing the motive for exercise and other associated symptoms that may point toward the diagnosis of an eating disorder.
Some of the most serious athletes in the world walk this fine line of obsession and addiction with every training run. Coaches need to be aware of both the psychological and physical warning signs that an athlete is falling into this trap. It is much more difficult to reverse the psychology after breaching the point of exercise addiction, and professional intervention may be required. It is the coach’s responsibility to create a healthy mindset and training atmosphere whilst keeping the training intensity high enough for performance gains.
Ensuring that an athlete takes rest seriously and recovers on “easy” days without deviating from an “easy” pace, are two simple ways to keeping an overly driven athlete in check. For those self-coached athletes, it is even more imperative to take a step back from yourself and do a self-assessment, asking your own body from an objective standpoint and answering honestly. It’s important to remember that a healthy athlete, both mentally and physically, will have a more sustainable, successful athletic career without sacrificing other needs and obligations in life.
DeCoverly Veale, D. M. W. (1987). Exercise dependence. British Journal of Addiction, 82(7), 735-40.
Freimuth, M., Moniz, S., & Kim, S. R. (2011). Clarifying exercise addiction: Differential diagnosis, co-occurring disorders, and phases of addiction. Int. Journal of Environmental Research and Public Health, 8, 4069-81.
Gapin, J., Etnier, J. L., & Tucker, D. (2009). The relationship between frontal brain asymmetry and exercise addiction. Journal of Psychophysiology, 23(3), 135-42.
Modolo, V.B., Antunes, H. K. M., deGimenez, P. R. B., Santiago, M. L. D., Tufik, S., & deMello, M. T. (2011). Negative addiction to exercise: Are there differences between genders. Clinics, 66(2), 255-60.
There has been a long standing debate on whether or not higher volumes of endurance training equate to elite caliber athletic performances. While it is true that many elite athletes train with much higher volume and intensity than the recreational athlete, it certainly hasn’t been shown to be a necessary requirement in order to compete on this level. With increasing volume of training comes a heightened risk of injury, a potentially weakened immunity, and a greater chance of overtraining and burnout.
Each athlete is individually capable of handling a given workload, and until the body adapts, this volume should only slightly increase with caution so as to not shock the body into a fatigue- or injury-ridden state. Over time, as more training experience is acquired, this volume can gradually drift upward into the 60-, 70-, 80-, and even 100+ mile weeks. By no means should an inexperienced runner jump into a 120-mile week training plan and expect to escape unscathed; in fact, some of the highest caliber elite athletes operate at half that volume, under a specific, periodized program designed to substitute quality miles over a quantity of miles. However, others swear by the increases in volume as the key to taking performance to the next level. Is the reward of this high mileage training worth the risk?
It is well-established in research that exercise in either a high-intensity or high-volume capacity stresses the immune system, making an individual more susceptible to infection, especially immediately following a training session. Unfortunately, a wide breadth of this research involves recreational athletes and sedentary individuals (Mårtensson, Nordebo, & Malm, 2014). When considering this trend in elite athletes, one must consider that impact of lifestyle, training tolerance, recovery ability, and nutritional intake which can greatly affect the strength and resistance of an athlete’s immune system.
Continue reading the full article and other sport science research at https://simplifaster.com/articles/high-volume-endurance-training-risk-vs-benefit/
Athletes’ motivation is believed to play a fundamental role in both performance and perceived ability. Motivation comes from both internal external sources, so both nature and nurture contribute to the whole drive of the athlete. In many ways, the coach plays a pivotal “nurturing” role, responding to the emotional and physical needs of the athlete. The surrounding climate dictated by the coach, whether it be criticizing or motivational, will nevertheless affect the psychosocial well-being of the athlete. Research delineates two types of climate atmospheres: task-oriented and ego-oriented (Reinboth & Duda, 2004). Task-oriented climates encourage the mastery of the task at hand, skill development, and knowledge acquisition, while ego-oriented climates focus on the individual’s performance and effort in relation to other competitors (Reinboth & Duda, 2004).
Stress is an important consideration in an athlete’s overall well-being, may be thought of as inversely related to self-esteem. Coaches and associated coaching pressures are often perceived as a source of distress to athletes who embody the egocentric mindset and performance climate, but the same is not true for those aimed at task mastering (Pensgaard & Roberts, 2000). The ego-involving climate can endanger the athlete’s self-esteem with constant social comparison and questioning of adequacy (Reinboth & Duda, 2004). In the task-focused climate, self-esteem can be built up gradually with individual development/improvement measured only in comparison to the self on the basis of work ethic; emphasis on the process rather than the immediate outcome contributes positively to self-esteem (Reinboth & Duda, 2004).
One study by Ruiz-Tendero and Martin (2012) found that dedication was regarded equally by coaches and athletes as the number one most influential factor of motivated success. In the same survey, coaches and athletes alike voted injuries as the number one negative-impact factor on performance (Ruiz-Tendero & Martin, 2012). There is an ego-driven belief that pain endurance and winning are the strongest measures of an athlete’s reputation and success; coaches should strongly urge athletes to be smart about their competitive mindset and the damage consequence of training ignorance. Mental toughness is better measured with humble honesty rather than stubborn pride when sustained injuries challenge the athlete’s mental fortitude.
Continue reading the full article and other sport science research at https://simplifaster.com/articles/how-coaches-contribute-to-athletes-motivation/
The debate between manipulating carbohydrate and fat metabolism for various weight loss and performance outcomes has gone back and forth by researchers for several decades, with no conclusive evidence supporting the extreme elimination diets we see so heavily marketed today. In the 1990s, high-carbohydrate nutrition was favored by the sports nutrition guidelines, recommending that at least 55% of energy come from carbohydrates in a given day (Burke, 2010). For endurance athletes, this number was recommended at greater than 60%; however, the research failed to support ‘why’ athletes needed this sort of macronutrient ratio for training (Burke, 2010). The evidence came after the millennium when it was found that higher carbohydrate intake could reduce (though not completely prevent) overreaching stress symptoms such as fatigue, sleeplessness, hormone disruption, and sub-par performance (Burke, 2010). In fact, withholding carbohydrates during the first few hours of recovery may hinder the functionality of the immune system and accentuate the immunosuppression occurring post-exercise (Burke, 2010). In addition, it was not found that moderate carbohydrate intake provided performance enhancement over a high-carbohydrate intake, so the guidelines remain in favor of carbohydrate availability for training purposes (Burke, 2010). High-fat nutrition has renewed interest once again, but is there enough to support a case for today’s endurance athlete?
The availability of a given substrate in the body largely determines our body’s fuel of choice at rest (Spriet, 2014). Exercise increases the metabolic demand on the body several-fold upon beginning a training session from rest, after which the body strives to achieve a steady state of aerobic intensity where the proportion of carbohydrates and fats finds an equilibrium in relation to an individual’s preference of fuel source (Spriet, 2014). When the power output of exercise exceeds 60% of maximal oxygen uptake (VO2max), studies have shown a decreased reliance on fat oxidation as a fuel source (Spriet, 2014). This decrease in free fatty acid release at higher intensities is likely due to a diversion of blood flow from adipose tissue to contracting muscles (Spriet, 2014). Above 75% of the VO2max, the majority of energy is derived from carbohydrate use, specifically muscle glycogen, in moderately trained individuals (Spiret, 2014). This is an important concept to consider when an endurance athlete is aiming to compete at 70-75% of maximum for extended periods of competition. The question remains whether or not it is possible to “teach” the body how to metabolically prefer fat as a fuel source at these competition intensities, which would go against the “default,” so-to-speak, of our innate preference for carbohydrates at these speeds.
Carbohydrates have gotten a bad rap for supposedly contributing to an ever-growing trend of obesity and metabolic syndrome in our country. On a physiologic level, carbohydrate intake results in a release of insulin by the body to help shunt glucose into depleted cells, or in the case of an inactive population, into the fat cells for conversion and storage, resulting in excess weight gain. Upregulated insulin inadvertently inhibits the transfer of fat across membranes, blocking fat oxidation (also known as lipolysis) during exercise and even at rest (Spriet, 2014). The reverse is true also: in the presence of high-fat, carbohydrate metabolism is down-regulated (Hawley & Leckey, 2015). The proposed theories of high-fat, low-carb exploit this physiologic mechanism as a way to increase fatty acid oxidation at the expense of restricting carbohydrate intake. The attraction to high-fat, low-carb diets for athletes has recently caught the attention of many through the media highlights of any given elite who has successfully clinched a podium spot in a championship, purely by running on a ketogenic diet or the like. While these performances are being attributed to the nutritional habits of these athletes, the research says there is no correlation between increased fat oxidation and performance (Hawley & Leckey, 2015). Carbohydrate-, not fat-based fuels, are the rate limiting factor in performance in trained endurance athletes (Hawley & Leckey, 2015). Fat-rich diets directly impair rates of muscle glycogenolysis, limiting high-intensity ATP-production necessary for energy at these paces (Hawley & Leckey, 2015).
Continue reading the full article and other sport science research at https://www.freelapusa.com/keto-or-not-to-keto-that-is-the-question/
Plyometrics and Performance
One of the topics I am most interested in relates to plyometric training for endurance runners. An article by Ebben (2001) states that due to the instability of the surface of cross country running, it is estimated that 5-10% of energy in a 3-6 mile race comes from anaerobic sources. With that being said, it is important to train for this anaerobic component, even in a primarily aerobic sport. This can be done via the use of explosive plyometric exercises. Ebben (2001) discusses the principle of specificity as it relates to training in a sport-specific manner. Force application to the ground is extremely important in cross-country running, as it directly generates power for covering the greatest horizontal distance possible with optimal efficiency (Ebben, 2001). Plyometric training, especially in the single-leg modality is highly specific to the single-leg force application that occurs in a runner’s stride (Ebben, 2001). Plyometric exercises with a greater horizontal component are even more specific to running, such as multiple reactive single-leg hops moving forward (Ebben, 2001).
A study by Ramirez-Campillo et al. (2014) examined the use of plyometric training in highly competitive middle- and long-distance runners for the purpose of developing explosive strength in performance. Plyometric training is meant to adapt the stretch-shortening cycle (SSC) and increase the rate of activation of a muscle’s motor units (Ramirez-Campillo et al., 2014). This study was initiated because prior research lacked a sufficient number of participants, failed to evaluate the effects in elite runners, applied a very high volume of plyometric activity per study length, and/or failed to include a time trial to assess distance running performance change (Ramirez-Campillo et al., 2014).
The experiment included a simultaneous application of plyometric and endurance training to test the effect on both time trial endurance performance and explosive strength adaptations (Ramirez-Campillo et al., 2014). The plyometric exercises included a drop (depth) jump from 20cm and 40cm to test for maximum jump height and minimum ground contact time, a countermovement jump (with arms) for slow SSC action, a 20m sprint test to assess horizontal explosive strength with fast SSC action, and a 2.4km endurance test on an outdoor track (Ramirez-Campillo et al., 2014). Total plyometric training time was less than 60-minutes per week for the 6-week study (Ramirez-Campillo et al., 2014). The experimental group experienced a 3-time greater improvement in time trial performance than the control group; in all other explosive metrics, the experimental group improved significantly while the control group showed a reduction in performance (Ramirez-Campillo et al., 2014). I thought this study was well-done and covered a lot of the bases that were missing in prior research to-date. It’s important to see these adaptations in the elite population, since they are already highly efficient individuals, small gains in performance are crucial and highly visible with new training strategies. In the general, untrained or even moderately-trained population, it’s very easy to manipulate variable to create positive results; this is much more difficult to achieve in elite populations.
Continue reading the full article and other sport science research at https://simplifaster.com/articles/plyometrics-performance-bone-health/
The topic of nature versus nurture presents itself in the world of elite sporting events as a sustained debate. Are world class athletes born or bred? Is there a certain amount of practice that can turn the average athlete into an elite? There are two main theories which aim to explain both arguments in the spectrum of the debate: the genetic influence model and the deliberate practice model.
The genetic model argues that athletic potential and success is predicted by a predetermined set of genetic traits. These physical traits are polygenic, or coded my many genes, producing the ultimate elite phenotype (Tucker & Collins, 2012). The four most influential traits include: gender, height, skeletal muscle composition, and VO2max (Tucker & Collins, 2012). The most obvious influence on athletic performance is the drastic segregation of male and female performances; this in itself is proof of genetic predisposition to athletic potential. Height is developed by both nature and nurture (nutrition), and is very predictive of sport-specific success; for example, the height required for basketball players is not conducive to long distance running.
Studies have found a number of VO2max genes in untrained individuals, inherently genetic, and also genes activated by training, environmentally influenced (Tucker & Collins, 2012). VO2max is a strong predictor of maximal aerobic capacity and thus performance in endurance-based events. Being genetically gifted with a superior aerobic capacity automatically places the athlete in an advantageous position for accelerated graduation to the elite level. Skeletal muscle properties are subject to similar genetic and environmental influences (Tucker & Collins, 2012). Hence, an athlete born with greater strength capacity in his or her musculature will have an easier time transitioning into strength-based sports, such as football or wrestling.
The dominance of East African runners in the middle-and long-distance events is well-known, especially in the last decade where 85% of the top 20 ranks in the world have come from this region (Vancini et al., 2014). These runners are primarily of Kenyan and Ethiopian descent and classically possess high VO2 max, hemoglobin, hematocrit, tolerance to altitude, bland diets of rice and beans, optimal running economy, and optimal muscle fiber type composition (Wilber & Pitsiladis, 2012). Much research has explored the possibility that genetic factors have yielded an advantage in this particular population, especially genes responsible for anthropometric, cardiovascular, and muscular adaptations to training (Vancini et al., 2014).
Continue reading the full article at https://simplifaster.com/articles/nature-vs-nurture-determinants-athletic-potential/
Athletes and health enthusiasts alike constantly seek new and improved methods capable of eliciting sports performance and health benefits. The explosion of so-called “super foods” has called individuals to seek ingredient-specific solutions to support or enhance both health and athletic needs. These super ingredients come in whole-food and/or supplement form, based on personal preference. Analyzing the constituent ingredients of foods and their metabolic function within the human body has led to some very powerful discoveries for both the general and athletic populations. Uncovering the synergistic, additive, and/or negative effects of these ingredients has thus become a major focus of nutrition research over the last decade. Moderate evidence exists in support of fish oil, carnitine, Vitamin C, and tart cherry juice supplementation (4). High levels of evidence have been established regarding B-alanine, caffeine, creatinine, and recently, beetroot juice (4).
One of these once elusive power ingredients, nitrate, is a natural constituent of the beetroot plant. Beet root juice, beet powder, beet pill supplements, and the raw vegetable itself have all been disappearing off the supermarket shelves since the research on their many health benefits have gone viral. This article aims to unveil the physiologic mechanisms behind beet’s powerful effects in the human body and why they should become a health food staple in every diet.
Inorganic nitrate (NO3-) is a compound found abundantly in green leafy vegetables and beetroot, carrot and pomegranate juice. Once the nitrate-containing food or supplement is ingested, the inorganic nitrate metabolizes in vivo (within the body) to its bioactive form, nitrite (NO2-), which is then reabsorbed into the bloodstream and sent into circulation (1). The anaerobic bacteria located in the oral cavity, predominantly within the crypts of the tongue, play an integral role in completing this chemical reduction (1). Nitrite is further reduced into various function forms (NOx), including nitric oxide (NO), which exert various physiologic effects on the body. Plasma levels of NO2- have been shown to peak at three hours post-ingestion, and remain elevated for approximately five hours (1).
Nitric oxide plays a biological role in signaling the endothelium (inner lining) of smooth muscles to relax and vasodilate, subsequently enhancing blood flow to nearby tissue. Conditions of low oxygen, such as ischemia and hypoxia, and low pH in body regions promote the reduction of NO2- to NO, favoring its effects in areas of the body most deprived of oxygen and adenosine triphosphate (ATP), the body’s critical energy source. An increase in circulating levels of NO2- and NO protects hypoxic (oxygen-deprived) tissues, including damaged blood vessels and contracting skeletal muscle by improving blood flow to those areas.
The benefits of nitric oxide might invoke the question as to why one cannot supplement NO directly, as opposed to taking the inorganic precursor, however, the endogenous form is a gas produced from the amino acid L-arginine. Research shows that supplementation with L-arginine is also ineffective in elevating the nitric oxide levels in the body; it appears that the endogenous chain of mechanisms is critical for the complete reduction of NO3- to NO for its entry into circulation (1). Considering these physiological mechanisms, recent research efforts have been made to reveal the possible health benefits of nitrates for individuals with blood flow disorders and as an ergonomic aid for athletes.
The epidemic of chronic inflammatory conditions in the U.S. has led to the massive inflation of health care costs, which were estimated at $4 trillion dollars in 2015, or $14,000 per person; in fact, the chronic “lifestyle” diseases like diabetes mellitus, hypertension, and coronary artery disease are responsible for more than 75% of the nation’s annual cost of health care (1). The price of these inflammatory conditions often involves compromised epithelial tissue lining the blood vessels, and a malfunction in maintaining normal homeostatic levels of nitric oxide.
The implementation of Dietary Approaches to Stop Hypertension (DASH) diet largely focuses on the incorporation of nitrates into daily intake, at a rate that is 5-fold higher than the recommendations of the World Health Organization (WHO) (1). The DASH diet has become the gold standard “natural” prescription for individuals diagnosed with chronic disorders of blood flow. Some studies have even proposed that this diet is as efficacious as a single hypertensive agent for reducing blood pressure (1).
Ingestible NO3- can be delivered in the form of beet root juice (500mL or 2 cups), whole beet root, or in supplement form (NaNO3-) at 10mg/kg of body weight (1). Per 100g of fresh weight, leafy greens such as lettuce, spinach, celery, and beetroot typically contain over 250mg of nitrate (2). These unveiled health benefits propose that nitrate supplementation may be a low-cost option for the prevention and/or treatment of blood flow disorders.
Augmenting the bioavailability of nitric oxide will, theoretically, positively influence exercise performance due to its effects on improving mitochondrial respiration, glucose uptake, calcium handling within the muscle fibers, vasodilation, and angiogenesis (the generation of new blood vessels) (2). Nitric oxide delivers a greater amount of oxygenated blood to skeletal muscle by enhancing blood flow to deprived tissues (1). In theory, this increase in blood flow would also improve the perfusion of oxygen and nutrients to exercising muscles, and thereby enhance performance.
Studies have shown that beet root juice consumption delays the onset of VO2 consumption during high intensity exercise, which correlates to a reduced oxygen cost of submaximal exercise and enhanced fatigue tolerance (1). In one particular study, healthy, fit subjects having consumed 200g of baked beetroot (>500mg of NO3-) performed a 5K time trial at a 5% faster running velocity than those ingesting the placebo; additionally, the former group had a considerably lower rate of perceived exertion compared to their placebo counterparts (1). Specifically, conditions of low oxygen supply or delivery and/or low pH (acidic) will greatly promote the reduction of NO2- to NO, and thus enhance oxygen and nutrient delivery to exercising muscles. This piece of physiology is particularly useful for athletes training and/or racing at altitude, considering how hypoxic conditions elicit these deficits within the muscles.
Dietary NO3- has been shown to reduce the metabolic cost of ATP and creatine phosphate production, which would thus improve force production and enhance the efficiency of muscle contractility (1). In one particular study, following three days of NO3- supplementation, the mitochondria of the vastus lateralis [from the quadriceps] muscle were isolated and tested for their efficiency (1). Mitochondria are the energy-producing “powerhouses” of the cell, and are responsible for the generation of ATP through cellular respiration. The NO3- supplemented group yielded a 20% improvement in mitochondrial efficiency and a 45-64% decrease in basal oxygen consumption as compared to the placebo group (1). The efficiency of these cellular organelles is determined by the P/O ratio, which measures the ability of the cell to couple phosphorylation and oxidation; in other words, the ratio compares the number of phosphate molecules incorporated into ATP molecules against the amount of oxygen consumed in the process. Lower P/O ratios indicate poor cellular efficiency, whereas high ratios indicate that more ATP molecules are produced per oxygen reduction to water (oxidation). More ATP means more energy availability to the muscles, and delayed time to fatigue as a result.
Interestingly, the studies which have demonstrated positive results in athletic performance after nitrate supplementation have only been statistically significant in the 'healthy, fit' population, rather than the 'athletic, elite' groups of test subjects. It is suspected that highly-trained athletes, especially endurance athletes, have already established high levels of NO activity through extensive training, rendering nitrate supplementation less than effective (2). These athletic subjects would be expected to have increases in skeletal muscle capillary infiltration, eliminating the need for NO to compensate for hypoperfusion of oxygen and nutrients.
Recent evidence shows that nitrate may preferentially target type II muscle fibers to improve their contractile function under conditions of hypoxia and/or electrolyte deprivation (2). Type II muscle fibers are commonly referred to as the "fast-twitch" or anaerobic fibers, which are selectively recruited during high-intensity bursts of activity such as repeat bouts of sprinting and jumping. These fibers fatigue rather quickly into a state of hypoxia, with energy supplies capping out at roughly 90 seconds, thus indicating the need for nitric oxide's effects.
Speed-power athletes would benefit most from improving the efficiency of Type II fibers in this regard. A double-blind study by Rimer et al., assessed the acute changes in maximal cycling power and optimal pedaling rate in training cyclists (3). The study aimed to investigate whether NO3--rich beetroot juice (BRJ) could improve these power metrics during short bouts of maximum cycling efforts lasting three to four seconds as compared to an NO3--depleted placebo group (3). The tests were performed approximately 2.5-hours post-ingestion of the BRJ, since the effects of nitrates within the body peak between 2.5 and 3 hours, and thus should be ingested at roughly that duration prior to activity in order to elicit maximum effects (1, 3). The results of the study demonstrated that the acute dietary intake of NO3- significantly increased both maximum cycling power and optimal pedaling rate (3). This aspect of nitrate physiology has yet to be thoroughly explored by the research, but provides promising evidence for the speed-power athlete in its novel stages of exploration.
Ingesting dietary NO3- via diets abundant in nitrate-rich vegetables or juice, or by pill supplementation, may offer a low-cost, natural treatment methodology for individuals with blood flow disorders. Those looking to improve athletic performance, such as increasing time to fatigue and improving energy efficiency, can also reap the benefits of nitrate-rich foods. These benefits would be diminished with the use of antibacterial mouthwash or swimming in chlorinated pools, due to reduction of nitrate-reducing bacteria in the mouth; these two conditions should be avoided when trying to maximize the benefits of nitrate supplementation. The dose-dependent effect of nitrate supplementation in elite athletic populations has not been established as efficacious, but is now considered to be well-supported in both the general and fit populations.