Twin Studies

As each day is perfectly unique, no two people are ever perfectly identical. How much our genetics and our environment influence our individuality is a question Scientists have been exploring for centuries. Nature is our genetic make-up, which we get from our parents, while nurture is a combination of our environment and our choices. Each choice we make and the environment in which we live has an effect on who we are and what happens to us. Therefore, our genetics are not our destiny.  The infinite possibilities of nature and nurture make it difficult to figure out what causes increased risk of disease; nature or nurture? How can we isolate the few variables which provide causal relationships with diseases arising from our environment and lifestyle or our genetics?

One such ways is through studying twins.  Twin Studies have been performed since 5th century BCE and are significant in that they “help researchers tease apart nature, our genes, genetic code and nurture, our environment.” The modern father of twin study, Francis Galton, explored the effects of nature verses nurture in twins in 1875. To understand how twin studies can be differentiated between nature and nurture, one must understand that there are two types of twins; monozygotic twins (identical twins) and dizygotic twins (non-identical twins). Monozygotic twins, come from a single fertilized egg, (one egg and one sperm) and results in the twins sharing 100% of their genes, and the monozygotic twins are thus genetically identical.  Dizygotic twins, come from two individually fertilized eggs (2 eggs, 2 sperm) which are fertilized and in the womb at the same time, and result in the twins sharing 50% of their genes just like regular siblings.

Researchers from the medical, psychological and behavioral fields try to establish the relative contributions of the environmental and genetic factors which contribute to the risk for developing a given disease or behavior. Identical twins are identical in genetic make-up and thus any difference in diseases or behaviors is (almost) solely due to differences in the environment. The environment can be behaviors like exercise, nutrition, social group influence, intrauterine conditions or any number of things. While monozygotic twins often share much of their environment in the early stages of their lives as they ideally grow up in the same house at the same time with the same parents and social circle, they also differ in specific ways throughout life.  Those environmental differences can then be considered to explain different susceptibility to disease, different traits and different emotions.

Scientists are interested in finding monozygotic twins who were raised in different environments or have different lifestyle habits.  Such an approach allows scientists to isolate lifestyle factors by controlling for genetics.  For example, in one study done on monozygotic twins, who moved apart and one of which developed dementia focused on the contribution of lifestyle to developing the disease in a paper titled Potentially modifiable risk factors for dementia in identical twins. Scientists retrospectively found differences between the sets of twins with regards to lifestyle habits, such as education and physical activity diet and exercise. The results suggest that the monozygotic twin with dementia was significantly less educated and participated in less physical activity than their twin without dementia.

The use of monozygotic twins are the closest we are today, to having two individuals be genetically identical. With these unique individuals, we have gained knowledge leading to the underlying non-genetic causes of diseases, traits and behaviors as well as further understanding and possible treatments. For instance, using monozygotic twins where one is physically active and the other is sedentary, can show the positive effects and necessity of exercise, independent of genetics, in preventing chronic diseases. Exercise promotes overall health and healthy lifespan. Twin studies help us to understand the bigger picture of the effects of our genetics and our environment.

References:

Fraga, M. F., Ballestar, E., Paz, M. F., Ropero, S., Setien, F., Ballestar, M. L., . . . Esteller, M. (2005). From The Cover: Epigenetic differences arise during the lifetime of monozygotic twins. Proceedings of the National Academy of Sciences, 102(30), 10604-10609.

Gatz, Margaret et al. (2006). Potentially modifiable risk factors for dementia in identical twins. Alzheimer’s & Dementia. The Journal of the Alzheimer’s Association, Volume 2, Issue 2, 110-117.

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A Triathlon Legend.

iron-nun-race-new-tease_69e8c20cff71bed656121b79510f6e7b“We have all been given different talents. We have to dig deep and to discover them, and when we find them, we are obligated to use them for the greater good.”
– Sister Madonna Buder

With endurance events, the participation of older people has increased, now with 80-85 year old female and 84-89 year old age groups for men in the Ironman triathlon events and the 80+ age group for both genders in the marathon event. This is inspiring for us youngsters and interesting in the world of science as to how age and gender affects the performance of an individual. For coaches and athletes this information provides the base evidence needed for training plans, techniques and racing tactics to get each individual athlete to be as competitive as possible. In this blog I explore the affect sex and age has on performance, which disciplines of the triathlon are more important in final placing for male and female triathletes and look at a legendary lady who just keeps going no matter what.

Age as defined by the Oxford Dictionary is, “the length of time that a person has lived or a thing has existed.” From the research done by Romuald Lepers et al, titled Trends in Triathlon Performance: Effects of Sex and Age, they found that with age total performance time increased, but decreased times were more noticeable in the short sprint and Olympic distance triathlon events than in the Ironman endurance events. It was also found that these master triathletes have improved over all three triathlon disciplines and total triathlon times over the last 30 years, raising the question of whether these masters triathletes have met their performance abilities in the Ironman triathlon events yet. One lady who has done more than simple live or exist in the triathlon world, leaving her mark, is Sister Madonna Buder, an 86 year old female triathlete, who opened up two Ironman age groups, at 82 she completed her last Ironman event and has been inducted into the USA Triathlon Hall of Fame. When asked how she does it, she replied, “I do it by putting one foot in front of the other!”

In a research paper by Bahadorreza Ofoghi titled Performance analysis and prediction in triathlon they looked at the 5 disciplines of the triathlon, the swim, transition 1, bike, transition 2 and the run, as seen in the figure below.

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This study was done through the analysis of internationally recognized historical data over a four year period from 2008-2012  found with no surprise that athletes who had the fastest splits in all five disciplines, were predicted to finish in the top positions. The athletes that medal had splits that were 19.6 seconds of the winner in the women, and 15.7 seconds of the winner in the men. For the men in the Olympic Distance Triathlon, the faster the swim and run times of the athletes, the higher their overall positioning, with the bike portion not being a predictor of overall position. For the women in the Olympic Distance Triathlon, the faster the bike and run times of the athletes, the higher their overall positioning, with the swim portion not being a predictor of overall positioning. The time for both the transitions needed to be the quickest to not negatively affect either gender’s final place positioning.

With this evidence I would suggest taking a leaf out of Sister Madonna Buder’s book and keep moving forward one step at a time, no matter what age or gender you are you can accomplish great things. As female triathletes, it would be suggested that most time in training and race tactics should be focused on the bike and run portions, while for the male triathletes most training and tactics should be on the swim and the run portions. Of course female triathletes should still have a solid swim portion, and the men should have a solid bike portion, and ensuring great balance over all the 5 disciplines, remembering that the swim and the bike portions are followed by a full marathon, will ensure each athlete has the highest chance of their best performance.

References:

Buder, M., & Evans, K. (2010). The grace to race : The wisdom and inspiration of the 80-year-old world champion triathlete known as the iron nun (1st Simon & Schuster hardcover ed.). New York: Simon & Schuster.

Ofoghi, B., Zeleznikow, J., Macmahon, C., Rehula, J., & Dwyer, D. B. (2016). Performance analysis and prediction in triathlon. Journal Of Sports Sciences, 34(7), 607-612.

Lepers, R., Knechtle, B., & Stapley, P. J. (2013). Trends in triathlon performance: Effects of sex and age. Sports Medicine, 43(9), 851-63.

Oxford Dictionary. https://en.oxforddictionaries.com/definition/age.

More than the speed advantage of a wetsuit.

It’s a long day out on the Ironman course. Each athlete begins the day at about 3:30 am, starts racing at 7 am and, the last people in, end at around midnight, then it is food, shower and bed. These athletes make use of the full 24 hour day on race day ! If any triathlete thinks they will be sleepy in the morning on race day they have nothing to fear as they plunge into the cold water at an early hour. The Ironman triathlon starts with a 3.86 km swim in water temperatures ranging from 14 degrees C to about 27 degrees C. Wetsuits are required in the Ironman rule book for water temperatures at or below 16 degrees C and are banned for temperatures at or above 24.5 degrees C. As R.M Lang and G.G. Sleivert say in their summary of findings on the subject of Clothing, Textiles and Human Performance,  “Appropriate design and choice of clothing is important in maintaining thermal balance during exercise, particularly when environmental conditions are extreme.” The wetsuit helps maintain this thermal balance and therefore, it is an exciting moment when the Ironman officials rule the event a wetsuit allowing one, especially when the water is cold. In this blog I will look at the effects of the wetsuit on an individual athlete and why this ruling makes an athlete excited.

More than every second triathlete I know says that the swim is their weakness out of the three disciplines, and a lot of none triathletes say that the swim section is the one keeping them from doing a triathlon. What brought about the use of the wetsuit was to enable triathletes to compete without getting hypothermia from the cold water. In a study by Luis Parsons and S.J.Day they say that the wetsuits act as a layer fat, trapping in a layer of water between the skin and the neoprene material, where the water is warmed up quickly by the body, but their study was designed to look at a much bigger debate. The debate was questioning whether wetsuits would increase swimming speed, which to any non-swimmer would seem like a great idea, but to any strong swimmer might seem like an unfair advantage. The study was titled Do Wet Suits Affect Swimming Speed? For 14 male and 2 female triathletes it was found that for a 3ominute swim, more distance was covered while wearing a wetsuit than while not wearing a wetsuit, and the swimming speed increased by 7%. However, the debate was settled and the wetsuit rules passed in the favour of allowing swimming skill to be tested during the race, and not the ability of an athlete to handle the cold.

The wetsuit increases speed mostly due to the buoyancy it provides. This layer of “fat” that the wetsuit creates increases buoyancy much like that of a whale. This was proven through a study by L. Cordain and R. Kopriva in the Department of Exercise and Sport Science at Colorado State University, titled Wetsuits, body density and swimming performance, where body composition was studied, in its relationship to swimming performance, with and without a wetsuit. 14 female swimmers had their body density measured while wearing a wetsuit, not wearing a wetsuit, and wearing neoprene bands over their wetsuits on their legs to determine the effect of body density for 400m and 1500m trials. The results are shown in the graphs below for both distances.

For both the 400m and 1500m trials we can see that there was a large decrease in swim times between the leg bands and the wetsuit/ without wetsuit trials. There was also a significant decrease for both the wetsuit trial times compared with the without a wetsuit trial times. The study concluded that wetsuits do improve swim performance and that an increase in body density , where heavier athletes with a higher body fat percentage, tend to decrease swim performance compared to lighter athletes with a lower body fat percentage.

Some practical applications found from this research is such that in the interest of health and safety for triathletes wetsuits should be required to be worn by all athletes when the water temperature is below the international standard. Athletes should follow these requirements for their own safety, and the risk of not being able to complete the race due to hypothermia. For international water temperatures where a wetsuit is optional, the use of wetsuits should be seen as a standard piece of equipment available for use by all athletes giving them all an equal chance to increase their individual swim speed enabled by the wetsuit.

References:

Cordain, L., & Kopriva, R. (1991). Wetsuits, body density and swimming performance.British Journal of Sports Medicine, 25(1), 31. doi:http://dx.doi.org/10.1136/bjsm.25.1.31

Parsons, L., & Day, S. J. (1986). Do wet suits affect swimming speed? British Journal of Sports Medicine, 20(3), 129. doi:http://dx.doi.org/10.1136/bjsm.20.3.129

Laing, R. M., & Sleivert, G. G. (2002). CLOTHING, TEXTILES, AND HUMAN PERFORMANCE. Textile Progress, 32(2), 1-122.

Ironman 2016 Competition Rule Book, 3 may 2016.

Slow it down…keep running.

Triathlon: Eat. Sleep. Swim. Bike. Run. RECOVER. Repeat.

Triathletes have a long way to go, no matter what race day holds for you, a sprint, olympic or ultra-distance triathlon will keep you on the move.  From what one eats to how many hours one is on the bike, in the pool or running loops around the track, all is taken into account when one is creating a training plan. What are some of the most effective ways to efficiently use the time you are dedicating to training every day? Much research has been done on the importance of warming up, getting two-a-days in, fartlek workouts and doing some strength training. A small topic of warming down after a workout has been suggested, but not required as much by coaches, even simply within my own training. In this post I will look at the production of lactate during a triathlon and the evidence of the effectiveness of actively recovering after one exercises in order to flush the system of lactate and prevent decreased performance due to stiffness for the next exercise bout.

Lactate is always being produced in the body, and is produced at a faster rate in the body during exercise. This causes the concentration of lactate in the blood to rise if it is not used, or removed at the same or a higher rate than it is produced. If not used, the lactate builds up in the blood, pools in the muscles and  causes stiffness. In a paper titled The Kinetics of Lactate production and removal during whole-body exercise, they say that this stiffness is not caused by the lactate itself, but  by its effect of decreasing the blood pH from its normal at 7.4.5 to pH 7.05 during high exercise intensity, which in turn affects the energy producing reactions in the muscles. Lactate during low to moderate levels of exercise is used by the muscle, heart and brain cells, and can be converted back into glucose, the main energy source of the body, in the liver. It is therefore important to ensure that after  and during exercise there is an effort made to clear this lactate and promote optimal performance.

In a study done by C. Baldari, titled Relationship between optimal lactate removal, power output and olympic triathlon performance  it is observed that blood lactate rises during the swim section of the event and then decreases throughout the bike and run sections of the event. This finding suggests that lactate is being used or cleared as exercise continues over time. For athletes and coaches this is a great indicator that an organized training plan of high intensity followed by lower intensity exercise bouts should be performed in training to allow the body to adapt. This adaptation allows an athlete to perform at a higher level, accumulating lactate slower and reaching the point of exhaustion later. One way one can do this is to perform some form of active recovery at the end of any training session at an optimal lactate clearance level intensity of exercise, generally said to be at 50% effort.

In a continued study of the one above, titled Blood Lactate removal during recovery at various intensities below the individual anaerobic threshold in triathletes they look at the specificity of metabolic demands during and after the three events in a triathlon, the resulting blood lactate results, and explore four different recovery treatments. The highest level at which someone can work, while working completely aerobically (with abundant oxygen) preventing the accumulation of lactate is called the individual’s ventilatory threshold, and this was used as their basis for figuring out at what level would recovery be most optimum. They use eight male triathletes, and look at recovery being performed at the IVT 50% above IVT, 50% below IVT and passive recovery for each individual.

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From the graph we can see that with all three active recovery methods, there was a higher clearance of lactate than during the passive recovery. They found that the highest clearance of lactate occurred when one actively recovered at 50% below their IVT, and that clearance was highest between 1 and 20 minutes, and then it began to plateau.This research recommends that if we continue exercising at 50% of our IVT level after any exercise bout for a period of 20- 30 minutes, then we should see a decline in the amount of lactate in the blood and muscle. This is beneficial in that in prepares our body for lactate influx during intense exercise and increases an individual’s ability to clear it, improving recovery and improving performance. To start this recovery within one’s own training I would suggest adding in an easy 20 minutes at the end of each training session, at the end of which your heart rate and breathing rate should be back to the pre-workout levels.

 

References:

Baldari C, Videira M, Madeira F, Sergio J, & Guidetti L. (2005). Blood lactate removal during recovery at various intensities below the individual anaerobic threshold in triathletes. The Journal Of Sports Medicine And Physical Fitness, 45(4), 460-6.

Moxnes JF, & Sandbakk Ø. (2012). The kinetics of lactate production and removal during whole-body exercise. Theoretical Biology & Medical Modelling, 9, 7. doi:10.1186/1742-4682-9-7

Baldari C, Di Luigi L, Silva SG, Gallotta MC, Emerenziani GP, Pesce C, & Guidetti L. (2007). Relationship between optimal lactate removal power output and Olympic triathlon performance. Journal Of Strength And Conditioning Research / National Strength & Conditioning Association, 21(4), 1160-5.

McArdle, William D. Katch, Frank I. Katch, Victor L. (2015) Exercise Physiology: Nutrition, Energy, and Human Performance 8th Edition. Walters Kluwer Health; Baltimore, MD 21201 and Lippincott Williams & Wilkins; Two Commerce Square, 2001 Market Street, Philadelphia, PA 19103.

Wikipedia, the free encyclopedia. Lactic Acid. https://en.wikipedia.org/wiki/Lactic_acid & https://en.wikipedia.org/wiki/Ventilatory_threshold

It all comes with Practice and Experience!

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Triathlon is a three stage endurance sport with two quick transitions between the swim to bike and the bike to run stages. Performing all three stages at the best of one’s ability is the goal of any triathlete and with the bike and run portion making up the majority of the race these are the two aspects that most athletes focus on. For this reason, it is important for any triathlete to ensure that each stage is mechanically and physically efficient, allowing an athlete to perform at their best and reduce the chance of injury. As can be seen in the pictures above, the cycling triathlete goes from an almost horizontal and folded position to a vertical and extended position while running, with the mechanics being different in each position. Through this post it is said that the more experienced an athlete, with more training and focus on maintaining form from cycling to running, the more efficient they are and the less they feel any negative effect from the biomechanical demands of triathlon.

Running performance is crucial and can determine the final results of an elite triathlon race. Running economy after cycling can be deterred and in a study performed by Nicole K. Rendos et al, Sagittal plane kinematics during the transition run in triathletes, the effects of cycling on running form and economy were explored. A group of 28 subjects, all with varying amounts of triathlon experience, at least who ran or cycled for 30 minutes 3 times per week, were involved and their angles of spine extension, pelvic tilt, hip flexion and hip extension were measured. The first experiment was performed with each subject just running on a treadmill, and the second involved a cycling routine of 30 minutes before running on a treadmill. There were significant increases in spine extension, pelvis tilt and hip flexion, while hip extension decreased in the 14 minute transition from the bike to the run, showing that there is a change in the way the subjects run. This change decreases the running economy of the athletes and will therefore decrease their level of performance compared to the performance of an athlete that just runs without cycling before. These running adaptations after cycling have been said to increase the risk of injury in athletes during the run stage. No evidence was found to confirm this in the study as healthy subjects were used for testing. These changes were more evident in those athletes that were newer to triathlon, and with extended testing and training the possibility of injury may decrease.

For new athletes, the transition from cycling to running is a hard feeling to get accustomed to, and many a minute has been spent by beginners giggling away at how they look as they wobble from step to step after being in the saddle of the bike for a few hours (Yes, I am talking from experience!). But this does not seem to affect the elite section of our sport, and a study performed by Jason Bonacci et al, Neuromuscular control and running economy is preserved in elite international triathletes after cycling for both a light 20minute cycling bout and a 50minute high intensity cycling bout, confirms this theory that the famous wobble goes away with practice and leads to the theory that running form and economy is preserved from cycling to running in these elite athletes. So over time we should all be able to improve our running economy and performance and decrease any increased risk of injury by maintaining our pre-cycling running form.

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If we can minimize the change seen in the graph above between the control run, where no cycling is done before and the transition run after cycling, we will increase the motor unit recruitment or enable greater efficiency for the run.

Some simple recommendations for beginners has been used over the years to get athletes used to these transitions and slowly get them adapted to switching between the use of different muscle groups and racing posture associated with swimming, cycling and running. Gregoire P Millet and Veronice E Vleck in their education and debate article titled Physiological and biomechanical adaptations to the cycle to run transition in Olympic triathlon: review and practical recommendations for training; looked at the energy cost, which varies from 1.6% to 11.6% depending on the experience level of the athlete. The main cost being that athletes lean forward as they run after they dismount the bike, and developing the skills to prevent this leaning will potentially decrease the increased energy cost. The main skill used is called block training, and it is the practical application of performing cycling training bouts and immediately transitioning to running, to increase the familiarity of the bodies muscles to the changes in muscle use and body dynamics. It has been tried and tested and ask any triathlete if their 20th attempt at a bike to run transition feels different from their first and the answer will not surprise you! So keep going, stroke to pedal, pedal to step, be aware of your body position and mechanics as you train, so that with time and as you come to race you will become the best triathlete you can be!

References:

  • Millet, G. P., & Vleck, V. E. (2000). Physiological and biomechanical adaptations to the cycle to run transition in olympic triathlon: Review and practical recommendations for training. British Journal of Sports Medicine, 34(5), 384. doi:http://dx.doi.org/10.1136/bjsm.34.5.384
  • Rendos, N. K., Harrison, B. C., Dicharry, J. M., Sauer, L. D., & Hart, J. M. (2013). Sagittal plane kinematics during the transition run in triathletes. Journal of Science and Medicine in Sport, 16(3), 259-65.
  • Bonacci J, Saunders PU, Alexander M, Blanch P, & Vicenzino B. (2011). Neuromuscular control and running economy is preserved in elite international triathletes after cycling. Sports Biomechanics / International Society Of Biomechanics In Sports10(1), 59-71. doi:10.1080/14763141.2010.547593