Using NIRS to non-invasively monitor muscle oxygenation during exercise

Skeletal muscles are the basis of all movement in the human body, and athletes work years to train their muscles to be powerful yet efficient. Even if a single muscle could allow a person to lift a car, it would not be very useful if the muscle could no longer create forceful contraction again for several hours. The muscle also must be efficient in the use of oxygen, ions, and other substrates that allow for contraction to be able to quickly recover and be prepared for repeated contraction. Muscle oxygenation is particularly important for both endurance and power of a muscle because it is necessary to produce ATP to power muscle cells to contract. Heart rate and blood oxygen delivery are helpful for getting an idea of an athlete’s efficiency, but they do not tell the whole story for the muscle. At the muscle, the balance between delivery and consumption of oxygen explains its efficiency [1]. To measure muscle oxygen saturation, a technique called near-infrared spectroscopy (NIRS) is used to get real time data to inform athletes of the state of their muscles during training. This is a powerful tool for maximizing athletic gains in muscles from training and to see the state of the muscle over time and after rest.

Early NIRS instrumentation was contained to the lab, but recently portable versions have become more common, which is very important for its use in both the medical and research fields. In medicine, NIR has been used for study of septic shock, free tissue transfer, real-time tissue perfusion during surgery, cancer nanotechnology, and peripheral arterial disease.  For this post, the use of NIR in exercise will be highlighted. In exercise, NIRS is a great tool because it is a non-invasive method that can be applied locally to muscles or tissues of interest and provide real time data during exercise. NIRS is highly sensitive to changes in muscle tissue oxygenation [2, 3, 4], and it reflects the balance between oxygen delivery and utilization, unlike measurements of arterial or venous blood samples which have been used previously and are minimally invasive [2]. NIRS works by measuring the percentage of oxygenated hemoglobin to total hemoglobin (oxygenated and deoxygenated hemoglobin) to give muscle oxygenation. Hemoglobin is the main oxygen carrying protein in the blood and can carry 4 oxygen molecules (O2). Oxygenated and deoxygenated hemoglobin scatter NIR light (600-1000 nm) differently, so their relative concentrations can be found from their molecular absorption coefficients. To do this, three to four different wave lengths of light will be used to determine the concentrations of each based on the change in molecular absorption coefficients at different wavelengths (Fig 1). NIR light must be used as it: 1) passes through skin, bone, and most biological tissue, and 2) is the appropriate wavelength where the small amount of absorption that occurs is predominately from hemoglobin (Fig 2) [5].  As the muscle performs work, the muscle oxygenation will decrease as a function of the work and the training of the muscle.

Fig. 1: Molecular Absorption Coefficient Profiles for Oxygenated and Deoxygenated Hemoglobin [5]

Fig 2: Light Absorption by Wavelength [5]

 

 

 

 

 

 

 

 

 

 

A patent on google patent claims to leverage this technology in a wearable article of clothing for athletes to be able to measure muscle oxygenation real-time (Fig 3) [6]. The patent claims to be a method and apparatus for assessing tissue oxygenation saturation through two main claims that summarize to: a portable apparatus that is a wearable article capable of measuring oxygenation saturation of at least one of a skin dermis layer, adipose layer, or muscular fascial layer of a user during physical activity using at least one near-infrared spectroscopy probe including at least one near-infrared light source and at least one photodetector. In short, the patent is a claim on a portable, wearable NIRS device for tissue oxygenation levels. NIRS has been a research method for decades, so the novel part of this patent lies in the incorporation of this technology into a wearable article of clothing.

Fig 3: Figure from patent illustrating wearable shirt, shorts, and socks using NIRS

Fig4: Figures from patent showing example data of muscle oxygenation average during constant rate running at different grades (top) and real time data from medial gastrocnemius muscle during weighted exercise and unweighted control (bottom)

This patent pertains primarily to the measurement of tissue during exercise (Fig 4). This could be of use for athletes during training to be able to compare what levels of exercise cause certain levels of muscle oxygen saturation loss. For example, highly trained athletes often train at high altitude to reduce oxygen in the air so that their body adapts to becoming more efficient with oxygen usage. This prompts higher performance when returning to normal oxygen levels. Using NIRS could allow them to find a training regime that caused the same hypoxia in muscle without traveling to higher altitude (they will still miss out on some of the pulmonary and cardio vascular advantages that training at altitude can produce). This may also be helpful in rehabilitation as the change in muscle oxygenation is an indicator that the muscle is being used and can inform physical therapists if the patient is engaging the correct muscles during rehab. Additionally, the device may also have merit in the medical realm for monitor muscle oxygenation in patients with chronic heart failure, peripheral vascular disease, chronic obstructive pulmonary disease, and varying muscle diseases [3, 4].

  1. Patent title: Method and apparatus for assessing tissue oxygenation saturation
  2. Patent number: US20170273609A1
  3. Patent filing date: 2017-03-22
  4. Patent issue date: Patent Pending
  5. How long it took for this patent to issue: TBD
  6. Inventor(s): Luke G. Gutwein, Clinton D. Bahler, Anthony S. Kaleth
  7. Assignee (if applicable): Indiana University Research and Technology Corp
  8. U.S. classification: A61B5/0075
  9. How many claims: 20

References and Further Reading

[1] BSX Athletics https://support.bsxinsight.com/hc/en-us/articles/204468695-What-is-muscle-oxygenation-

[2] Bhambhani, Y. N. (2004). Muscle Oxygenation Trends During Dynamic Exercise Measured by Near Infrared Spectroscopy. Can. J. Appl. Physiol., 29(4), 504–523.

[3] Hamaoka, T., Mccully, K. K., Quarisma, V., Yamamoto, K., & Chance, B. (2007). Near-infrared spectroscopy / imaging for monitoring muscle oxygenation and oxidative metabolism. Jounal of Biomedical Optics, 12(6), 1–16. http://doi.org/10.1117/1.2805437

[4] Boushel, R., & Piantadosi, C. A. (2000). Near-infrared spectroscopy for monitoring muscle oxygenation. Acta Physiol Scand, 168, 615–622. http://doi.org/10.1046/j.1365-201x.2000.00713.x

[5] Shimadzu Commercial Website https://www.ssi.shimadzu.com/products/imaging/labnirs-principle-of-operation.html

[6] Patent https://patents.google.com/patent/US20170273609A1/en?oq=US20170273609A1

[7] Ferrari, M., Muthalib, Makii, & Quarisma, V. (2011). The use of near-infrared spectroscopy in understanding skeletal muscle physiology : Phil. Trans. R. Soc. A, 369, 4577–4590. http://doi.org/10.1098/rsta.2011.0230 

[8] Artinis Commercial Site https://www.artinis.com/portamon#portamon-software

DOMS: Why do your muscles hurt days after exercise?

Chris Hernandez and Christian Poindexter

Soreness is a typical and often expected side effect of any moderate level of physical activity or exercise.  However, contrary to popular belief, there are many different types of soreness which are a result of separate things. For example, the soreness that many people experience during or immediately after exercise is known as acute soreness. Acute soreness typically develops within a couple of minutes of the muscle contraction and dissipates within anywhere from a few minutes to several hours after the contractions have ended[1].  It is widely accepted that this soreness is a result of the accumulation of chemical byproducts, tissue edema, or muscle fatigue.  Delayed Onset Muscle Soreness (DOMS) typically develops between 12-24 hours after muscle contractions end, with peak ‘soreness’ being experienced 24-72 hours after the exercise is over[1].  Exercises typically associated with DOMS include strength training exercise, jogging, walking down hills, jumping, and step aerobics. Apart from soreness, people suffering from DOMS also experience swelling in their sore limbs, stiffness of adjacent joints, tenderness to the touch, and temporary reduction of strength in affected muscle[1].  Unlike with acute soreness, there are several competing theories on the cause of DOMS, none of which have been ultimately proven to be the predominant cause.  

One of the first and most touted theories was the Lactic Acid Theory.  This was based on the concept that the muscles continue to produce and accumulate lactic acid even after the exercise is abated.  The accumulation of this lactic acid is thought to cause the noxious stimulus associated with soreness[2].  The paper we are using, “Delayed Onset Muscle Soreness: Treatment Strategies and Performance Factors”, cited a study done by French researchers regarding misconceptions about lactic acid, and more specifically lactate[3].   This study goes on to explain that during the recovery phase post-contraction, accumulated lactate gets oxidized by lactate dehydrogenase (LDH) into pyruvate.  This pyruvate is either oxidized in the mitochondria where it contributes to the resynthesis of ATP, or it is transported in the blood to be used or disposed of elsewhere in the body[3].  It has been observed that for test subjects whose lactate levels were monitored for 72 hours before, during, and after exercise, their lactic acid levels returned to pre-exercise levels within 1 hour of the cessation of exercise[2].  Since DOMS does not set in for 24-48 hours, it is very unlikely that lactic acid accumulation is the cause of the pain and other symptoms associated with this disease.  

These researchers did note some conditions however that were noted to affect the lactate levels of those participating in the study.  For example, a participant with a diet rich or low in carbohydrate concentrations can cause lactate levels to decrease or increase respectively[3]. Further, participants who had undergone strenuous exercise the day before are likely to show signs of glycogenic depletion, which could cause them to have irregular lactate levels[3]. Further, the type of exercise performed was also shown to have an effect on not only lactate levels but also on the time frame required for levels to return to normal[3].  To improve this study and potentially get better results it would be best to make sure that all test subjects were undergoing the same exercise regimens.  It would also be beneficial if the amount of carbohydrates (based on body weight) was held standard, and that they all experienced 48 hours of rest before data collection[3].  However, even given these potential weaknesses, given that the lactate levels return to below normal within an hour of exercise cessation, it can be said with reasonable certainty that lactic acid is not the cause of DOMS[2,3].

A more current and well-supported theory is the Muscle Damage theory, which is based on the disruption of the contractile component of muscle tissue after eccentric exercise. Type II fibers have the narrowest z-lines and are particularly susceptible to this type of disruption. Nociceptors located in the muscle connective tissue and in the surrounding tissues are stimulated, which leads to the sensation of pain that we know as DOMS. In practice, muscle soluble enzymes can be used as an indicator of z-line disruption and sarcolemma damage. Creatine Kinase (CK) is used as one of these muscle permeability indicators; any disruption of the z-lines and damage to the sarcolemma will enable the diffusion of  CK into the interstitial fluid, where it can be measured.

To test the connection between eccentric exercise and changes in CK, this study[4] used five healthy adults and had them walk on a treadmill for an hour at a 13-degree incline to test the effect of concentric exercise, and then a 13-degree decline five weeks later to test eccentric exercise. Venous blood samples were taken pre-test and every 24 hours until CK levels had returned to pre-exercise levels. Following downhill walking, all subjects reported muscle pain and tenderness in the calves and glutei muscles, which developed several hours post-exercise and was maximal between 1-2 days after. The severity of pain differed between subjects, but following uphill walking none reported any pain or tenderness. Both concentric and eccentric exercises showed increases in CK levels, but eccentric work showed much greater levels and peaked after 4-7 post exercise, as shown in figures 1-2.

Newham, et al. conclude that rises in CK levels are a result of eccentric work, and suggests that the extent to which muscle is lengthened and the level of habituation to eccentric work play a role in the enzyme response, and thereby in DOMS. However, they acknowledge that there is only a correlation between CK levels and DOMS and not necessarily a causation. Additionally, the sample size they used is small which could lead to inaccurate data.

There are many theories of the cause of DOMS, and none can fully explain the phenomenon. A combination of models has also been proposed[5], drawing aspects from various theories. Of the two theories we examined, the muscle damage theory was the most conclusive, showing a relationship between plasma CK levels and DOMS. Additional studies will be necessary to determine whether the muscle damage theory, another theory or possibly a combination of multiple can best explain the symptoms of DOMS.

 

Questions to Consider:

  1. Which types of exercise would help to prevent DOMS?
  2. How would you better design an experiment to correlate DOMS with enzyme activity?
  3. Can we conclusively rule out lactic acid as an explanation?

 

References/Further Reading:

[1] American College of Sports Medicine. Delayed Onset Muscle Soreness. Delayed Onset Muscle Soreness, American College of Sports Medicine, 2011, www.acsm.org/docs/brochures/delayed-onset-muscle-soreness-(doms).pdf.

[2] Schwane JA, Hatrous BG, Johnson SR, et al. Is lactic acid 63. Hasson SM, Wible CL, Reich M, et al. Dexamethasone related to delayed-onset muscle soreness? Phys Sports Med phoresis: effect on delayed muscle soreness and muscle function 1983; 11 (3): 124-7, 130-1

[3]Léger , L., Cazorla , G., Petibois , C. & Bosquet , L. (2001). Lactate and exercise: myths and realities. Staps , n o 54, (1), 63-76. doi: 10.3917 / sta.054.0063.

[4]Newham, D. J., Jones, D. A., & Edwards, R. H. T. (January 01, 1986). Plasma creatine kinase changes after eccentric and concentric contractions. Muscle & Nerve, 9, 1, 59-63.

[5]Cheung, K., Hume, P. A., & Maxwell, L. (2003). Delayed Onset Muscle Soreness. Sports Medicine,33(2), 145-164. doi:10.2165/00007256-200333020-00005

[6]Armstrong, R. B. (January 01, 1990). Initial events in exercise-induced muscular injury. Medicine and Science in Sports and Exercise, 22, 4, 429-35.

Wheying the Benefits of BCAAs in Exercise

Andrew Reynolds and David Appleby

After hitting the gym, playing sports, or even going for a run, many athletes turn to protein and amino acid (AA) supplements to enhance muscle recovery and growth. Multiple studies suggest that individuals who regularly exercise or partake in high intensity training require more dietary protein and AAs than sedentary individuals. This additional protein not only allows the human body to repair itself, but is also required for everyday metabolic activities and immune function. Of the twenty amino acids that comprise muscle protein, nine are considered essential amino acids. These essential AAs are not able to be produced by the body on its own, and therefore must be ingested through one’s diet. While it is possible to obtain the necessary protein and nutrients through a regular balanced diet, evidence shows that supplementation before and after exercise may prove advantageous. Among the most popular and cost efficient are powdered proteins, found most commonly in the form of whey and casein. Whey protein, often referred to as “fast” protein, has been shown to elicit a sudden, rapid increase of plasma amino acids following ingestion, providing immediate delivery to the body. Casein, however, is known as “slow” protein and induces a rather progressive and prolonged increase in plasma amino acids. While the digestion of these different proteins has been found to mediate protein metabolism and synthesis after exercise, it is debated whether the use of branched-chain amino acids (BCAAs) augments these processes on its own.

 

The branched-chain amino acids make up approximately one third of skeletal muscle protein in the body, and account for three of the nine essential AAs. Of the three BCAAs are leucine, isoleucine, and valine, which have laid the foundation for a multi-million dollar industry of nutritional supplements. Distributors of BCAA supplements rave of their anabolic capabilities and claim of their role in muscle recovery when taken post-exercise, particularly in regard to leucine. Leucine has been said to not only act as a precursor for muscle protein synthesis, but also a regulator of intracellular signaling pathways involved in the process of protein synthesis. A few studies have reported that the ingestion of BCAAs increases protein balance either by decreasing the rate of breakdown, increasing the rate of synthesis, or a combination of both. Additionally, it was observed that pairing leucine supplements with carbohydrates and protein before and after workouts led to a heightened level of protein synthesis in the body when compared to trials where leucine was not present. However, the credibility and repeatability of the research behind these claims is unclear, and has been rebutted by other scientific studies.

In this study assessing BCAAs and muscle protein synthesis in humans, the idea that BCAAs alone are capable of promoting muscle anabolism is questioned. This claim has been put forward for more than 35 years, but has been chiefly recorded in rat and other animal studies, with almost no studies being conducted regarding the response to oral consumption. The study involves a detailed literature search, and evaluates the theoretical and empirical data used to make these initial claims regarding BCAAs. It discusses how skeletal muscle in humans comprises a much larger portion of total body mass than in rats and therefore leads to several differences in the way muscle protein synthesis is regulated. Another problem with these previous studies is that they often use the “flooding dose” technique, which involves the administration of an amino acid tracer over a very short time period, therefore neglecting any possibility of sustained effects. With that being said, many of the results found in past experiments employ methods that make the extrapolation of the data to humans unfitting and reduce the physiological significance. In addition, this study displayed how only two studies were conducted analyzing the intravenous effects of BCAAs in humans, noting in both that BCAAs decreased both muscle protein synthesis and protein breakdown. However, the rate of the catabolic processes that broke down muscle protein exceeded the rate of protein synthesis in both cases during BCAA infusion. Due to these findings, the researchers refuted the claim that consumption of dietary BCAAs initiates anabolic activity and increases muscle protein synthesis.

Overall, it is evident that additional attention to diet and supplementation is essential for athletes and individuals who regularly exercise in order to promote the growth and repair of muscles, and to maintain a healthy body. While use of protein powders in the role of muscle protein synthesis has been backed by extensive scientific research, it is still unclear of the extent to which BCAAs are capable of carrying out these same processes on their own. More studies need to be conducted in human subjects observing the activity and metabolism of proteins when dietary BCAAs are ingested to better determine the effectiveness of their use. Many factors come into play when assessing the best supplements to take in regards to exercise, including intake quantity, timing of ingestion, and interaction effects. After observing the conflicting research claims, the use of BCAAs alone may not yield noticeable results, but seems to have little to no risk involved in taking them. Many trainers and workout regimens advise the combination of protein supplements and BCAAs to maximize benefits, but the scientific research is still lacking.

Questions to Consider

  1. What would happen if an individual took more protein supplements/BCAAs than the body needed?
  2. How could studies be better designed to assess the role of BCAAs in humans?

Further Suggested Reading

[1] https://www.ncbi.nlm.nih.gov/pubmed/20048505

[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5568273/

[3] https://www.ncbi.nlm.nih.gov/pubmed/16365096/

[4] https://jissn.biomedcentral.com/articles/10.1186/1550-2783-4-8

[5] http://healthyeating.sfgate.com/primary-role-protein-diet-3403.html

Cupping Therapy: Is it Worth the Bruises?

By Daniel Owens and Jeremy Grunden

Cupping is form of alternative medicine that is said to help with pain, inflammation and blood flow. All of this can lead to better well-being and relaxation as it acts as a form of deep tissue massage. While not that popular, you may have seen it being used during the Rio Summer Olympic games in 2016. Many athletes, such as Michael Phelps, were seen with large purple spots along their body. This is the result of cupping therapy. Cupping is usually put into two categories; wet and dry. Dry cupping involves the suction of the skin into the cup. Wet cupping has one extra step in which an incision is made, and blood is drawn from the suctioned area. While Olympic athletes seem convinced, is there any scientific data to support cupping as a valid therapy for recovery and rehabilitation?

First, we will look into rehabilitation. A study from Evidence-Based Complementary and Alternative Medicine attempted to prove the efficacy of cupping therapy for treating chronic neck and shoulder pain. The three things that they were looking for was skin surface temperature, blood pressure, and pain intensity. They had a cupping and a control group and found cupping to be statistically significant in raising the skin surface temperature and lowering the pain intensity (Figure 1). The conclusion was that cupping causes vasodilation and can increase blood circulation and is therefore an effective therapy for chronic neck and shoulder pain. These results are not without some cause for concern. First off the sample size was relatively small and similar. Also the increase in skin surface temperature is to be expected, however the pain intensity could be attributed to a number of things. Pain tolerance between patients is different and the decrease in pain intensity of the cupping group could be a result of the placebo effect.

One case study looked into utilizing cupping therapy as a means of treatment for vascular thoracic outlet syndrome. Vascular thoracic outlet syndrome is when blood vessels and nerves near the collarbone are compressed. This restricts blood flow and can lead to pain and numbness along the shoulder and down to the fingers. The case study focused on a collegiate baseball pitcher who had been diagnosed with the disease. The pitcher was put on a program that included cupping therapy on alternating days combined with certain range of motion exercises. The patient began to pitch again and noted no swelling, increased range of motion and significantly less pain. All of this would suggest that the cupping therapy was effective in treating this ailment. However, some issues with the case study is that they did not continue to follow up with the patient after the 3 week period and the sudden improved health could be attributed to a number of different factors. The authors do admit that more research and testing must be conducted to fully understand the efficacy of cupping therapy.

In regards to recovery, a study was done by a team of Greek researchers to find how cupping therapy compares to other treatments in the combating of myofascial pain syndrome. Myofascial pain syndrome is caused by painful spots in the fascia surrounding the skeletal muscle due to repetitive injury, training overload, and muscular overuse. Cupping was done to 20 amateur soccer athletes once a week for three weeks, and their pain pressure threshold (PPT) and visual analogue scale (VAS) was taken before and after the treatment sessions. An increase in PPT and a decrease in VAS was observed in the athletes after cupping. These changes suggest that cupping does have an effect on the body. It’s stated in the article that researchers believe cupping causes hyperemia and local stretching, which is similar to what the first study concluded.

These results show that cupping seems to improve recovery, however other recovery techniques appear to be more effective. Cupping saw the smallest change in the pre and post values. Additionally, it’s always important to consider each participant’s pain tolerance varies. This helps to explain why the standard deviation was ~1.5 for all values in table one.

Compiling all of the evidence, it seems cupping does have an effect on rehabilitation and recovery. Cupping causes vasodilation and hyperemia. This increase in blood circulation and dilation of the blood vessels helps to combat illness that are caused by constricted/compressed blood vessels, like vascular thoracic outlet syndrome. According to the third article though, cupping may not be the most effective recovery solution. When considering the cost of each treatment method, availability, and preference, cupping may not always be the best solution for recovery.

Questions to Consider:

 

  1. When would cupping therapy be ideal to use?
  2. How is cupping therapy better than other therapies?
  3. Can cupping therapy be combined with other techniques to boost its performance?

Further Readings/References:

Ahmadi, Alireza, et al. “The Efficacy of Wet-Cupping in the Treatment of Tension and Migraine Headache.” The American Journal of Chinese Medicine, vol. 36, no. 01, 2008, pp. 37–44., doi:10.1142/s0192415x08005564.

Bridgett, Rhianna, et al. “Effects of Cupping Therapy in Amateur and Professional Athletes: Systematic Review of Randomized Controlled Trials.” The Journal of Alternative and Complementary Medicine, vol. 24, no. 3, 2018, pp. 208–219., doi:10.1089/acm.2017.0191.

Jun, Wu. “Experimental Study on Treatment of Chronic Soft Tissue Injuries with Fire-Needle Therapy.” Chinese Acupuncture & Moxibustion, 2002, doi: R245.316.

“Fire Cupping-2.” Flickr, www.flickr.com/photos/psit/4827714792.

Epigenetic Muscle Memory

What comes to mind when I hear the term muscle memory is the typical example being able to ride a bike with ease even if you haven’t ridden one in a long time.  This time of memory is neurologic and comes from repetition of motor tasks. It primarily involves the dorsolateral premotor cortex and cerebellum.[1] However, there is a different kind of muscle memory that a recent study just discovered a lot about.[2] This muscle memory is referring to epigenetic changes to the DNA of human skeletal muscle.

Epigenetics is changes that affect gene expression without altering the DNA sequence but instead turn on and off specific genes. Three ways that genes can be silenced are DNA methylation, histone modifications, and RNA-associated silencing.[3] DNA methylation is what plays a key role in muscle memory and is a major part of the study.  It is a chemical process of adding a methyl group onto DNA that only occurs where cytosine and guanine nucleotides are next to each other and the guanine is linked to a phosphate.[2] This is referred to as a CpG site.

This study used 8 healthy males with no previous training. They went through three phases: loading, unloading, and reloading. Whole-body DEXA and vastus lateralis muscle biopsies were taken at baseline and at the end of each phase. Over 850,000 CpG sites were investigated. Many genes where found to be hypomethylated and showed increased gene expression. This epigenetic memory of earlier muscle growth means that at a later time there can be a greater response to exercise and more muscle growth.

 

As a person who has encountered many injuries and been forced to take multiple weeks off from the gym, it is comforting to know that despite the loss in strength that occurs during the time off my muscles will hold this memory and be more capable of regaining it.

One possible major implication of this study is a change in bans due to performance enhancing supplements, as this could mean the effects may be much longer lasting. Should people caught using them ever get to return to their sport knowing this? More research needs to be done on this specifically before real decisions can be made on this but it is definitely a future path for this research

 

References and further readings

[1] Robb T. How to play like a pro: The neuroscience of muscle memory. Oxford Neurological Society. http://neurologicalsociety.org/play-like-pro-neuroscience-muscle-memory/. Published 2016. Accessed March 14, 2018.

[2] Seaborne RA, Strauss J, Cocks M, et al. Human Skeletal Muscle Possesses an Epigenetic Memory of Hypertrophy. Sci Rep. 2018;8(1):1898. doi:10.1038/s41598-018-20287-3.

[3] Simmons, D. (2008) Epigenetic influence and disease. Nature Education 1(1):6

[4] Improving your Muscle Memory – Making Good Technique Automatic. National Federation of State High School Associations. https://www.nfhs.org/articles/improving-your-muscle-memory-making-good-technique-automatic/. Published 2014. Accessed March 14, 2018.

[5] Sharples AP, Stewart CE, Seaborne RA. Does skeletal muscle have an “epi”-memory? The role of epigenetics in nutritional programming, metabolic disease, aging and exercise. Aging Cell. 2016;15(4):603-616. doi:10.1111/acel.12486.

Research Says: CrossFit vs. Bodybuilding, Apples to oranges or two sides to the same coin?

Recently workout fads have been popping up all over mainstream media and in different fitness centers. Everyone seems to have the ultimate plan to burn fat and build muscle, these routines have become more intricate and choreographed, often requiring a coach or instructor to oversee the work out. Older workout conventions have had to adapt to meet the changing needs and desires from society. We are here to figure out, is CrossFit the ‘glow up’ of Body building or are these two style of exercise completely unique?

First, what are CrossFit and bodybuilding?

Example of a typical CrossFit exercise

CrossFit is recognized as one of the fastest growing high intensity functional training regimens to date, popping up in 142 countries worldwide. But what is this mysterious new fad and does it actually work?  The purpose of CrossFit training is to get as ‘fit as personally possible’, but is not specifically focused on just one fitness area. CrossFit aims to optimize physical ability not only in strength, but in cardiovascular endurance, flexibility, power, speed, coordination, agility, balance, and accuracy as well [1]. This lead trainers to develop a plan that incorporates multiple training theories into one ‘Workout Of the Day’ to keep a variety of fitness elements working.These workouts involve elements from gymnastics, weightlifting, and cardiovascular exercises which are performed quickly with little rest between sets.

The goal of Bodybuilding (muscle specific) training is so lose as much fat content as possible while maximizing your bodies muscle mass. This kind of training is where terms like ‘leg day’ and ‘back day’ came from, it is devoting an entire workout to a few muscle groups and working them to exhaustion. When you undergo this type of training your body experiences hypertrophy of all muscle fiber types.[2] A bodybuilding workout focuses on keeping the heart rate steady and high weight low rep exercises to slowly break down and rebuild one’s muscle fiber. This is proven to be an effective method if one is only worried about shear size and growth of muscles [3].

Expected muscle growth of Bodybuilders

After hearing this do you believe they are the same? Here’s what science said.

The approaches of these two exercise styles are most definitely unique, but are the fitness results actually all that different? In one research study called “Functional vs. Strength Training in Adults” 101 subjects, averaging an age of about 55, were separated into two groups that each performed 24 sessions of (functional or strength) training protocol twice per week. Each subject was assessed before and after the study using a quantitative Y-balance test and a qualitative Functional Movement Screen test. The changes between pretest and post test were analyzed and results showed that there were no significant differences in improvement between the training protocols as a whole. However, functional training was less effective for women compared to men in the same group [4]. The variability in prior athletic training must be taken into consideration when interpreting these results. Some participants may have needed additional training to better their basic skills before partaking in these specific training protocols. 

Another study looked at ‘The effects of high-intensity intermittent exercise(HIIE) training on fat loss and fasting insulin levels of young women”[5] comparing the effects of CrossFit(HIIE) training to steady state weight lifting over the course of 15 weeks(exercising three times a week). While this study focused on insulin levels they reported a variety of information on lean body mass, fat content, and weight loss that can be used to draw conclusions about the exercise types as well, see that diet was not changed between the groups. This study showed that women who underwent the CrossFit style training showed a significant decrease in total body mass(they lost more weight) 3.5kg weight loss, compared to  the steady state weight lifters who showed a 0.5kg increase in body mass. Demonstrating that while CrossFit participants and bodybuilders may both be used for strenuous high demand exercise, CrossFit is a more effective method of losing weight whereas bodybuilding promotes the act of ‘bulking up.’ While this study was full of information, it does not completely validate the idea that Crossfit and Bodybuilding are the same results with a different method it does help share some information that can point future studies in the right direction.

Based on what we have found we can draw a similar conclusion to previous posts about these training styles. We concur with the groups from previous years that current studies show that while the methods of achieving a lower fat content are different, the overall outcomes of the training types are very similar. In order to better compare these two very different approaches to fitness, there needs to be more extensive research done. The current scientific literature related to CrossFit specifically is lacking. Few studies with high level of evidence at low risk of bias have been widely recognized [1]. As of now we cannot truly compare this new workout fad to the traditional bodybuilding without more extensive studies with conclusive evidence.

By; Ellen Dudzinski and Destiny Neumann

Questions to consider:

  1. Are CrossFit and bodybuilding the only ways to build muscle quickly and effectively?
  2. Is CrossFit or bodybuilding for everyone, why or why not?
  3. What athletes should attempt at least one of these training types?
  4. After reading this, how would you further evaluate the similarities and differences between CrossFit and bodybuilding?
  5. Would supplementation increase the results from either training style?

Suggested Readings:

Karavirta, L., M. P. Tulppo, D. E. Laaksonen, K. Nyman, R. T. Laukkanen, H. Kinnunen, A. Häkkinen, and K. Häkkinen. “Heart rate dynamics after combined endurance and strength training in older men.” Medicine and science in sports and exercise. July 2009. Accessed March 06, 2018. https://www.ncbi.nlm.nih.gov/pubmed/19516157

Aagaard, P., and J. L. Andersen. “Effects of strength training on endurance capacity in top-level endurance athletes.” Scandinavian journal of medicine & science in sports. October 2010. Accessed March 06, 2018. https://www.ncbi.nlm.nih.gov/pubmed/20840561.

Fitts, R. H., and J. J. Widrick. “Muscle mechanics: adaptations with exercise-training.” Exercise and sport sciences reviews. Accessed March 06, 2018. https://www.ncbi.nlm.nih.gov/pubmed/8744258.

Fitts, R. H., D. R. Riley, and J. J. Widrick. “Functional and structural adaptations of skeletal muscle to microgravity.” The Journal of experimental biology. September 2001. Accessed March 06, 2018. https://www.ncbi.nlm.nih.gov/pubmed/11581335.