Common Triathlon Training Metrics



Over the past two weeks I have outlined how to conduct a heart rate test and a functional threshold power test; but, I realized that I should have started from the beginning. What are the various training metrics that a triathlete should use?

Coaches, athletes, and endurance sport authors love to talk training metrics and terminology. Lactate threshold. VO2max. Cardiac output. Heart rate. Power. Rate of perceived effort. The list can go on and on…

Let’s look at a few key metrics that any triathlete or endurance sport athlete should understand, or at least a basic understanding.

  • Heart Rate – The very basic definition of a heart rate is the number of heartbeats per unit of time. Heartbeats are created when blood flows through the heart and the values open and close creating an audible sound. The normal human heart beats at 60-100 beats per minute (bpm). This, of course, depends on various factors such as fitness, age, stress, etc. Heart rate in fitness is an important metric because it can measure an athlete’s fitness. Through regular endurance training, the heart becomes stronger and thus can pump more blood with each beat. As a result, the heart doesn’t have to work as hard, and the athlete’s heart rate at rest and during exercise will be lower. Measuring an athlete’s heart rate over time is a good way to measure improvement in an athlete’s endurance fitness. See how to conduct a heart rate test for more information on heart rate-based training.
  • Cardiac Output – Cardiac output is measured as the amount of blood that the heart pumps through the body at a single minute. An increase in cardiac output is important because more blood is delivered to the important organs, such as the brain and liver. Cardiac output increases with regular endurance training. During endurance sports, cardiac output is an important metric because it means that more blood is delivered to the working skeletal muscles during a workout. As a result, more oxygen is transported to the muscle cells to produce energy and other metabolic waste by-products are removed from the working muscles more rapidly.
  • VO2max – Endurance training not only improves cardiovascular fitness, but also improves lung capacity during exercise. Endurance training generally improves an athlete’s respiratory rate (breathes per minute) and tidal volume (amount of air per breath). Improvements in respiratory rate and tidal volume can contribute to an increase in maximal oxygen uptake, also known as VO2max. VO2max is defined as the highest volume of oxygen that a person’s body is capable of taking in and using during aerobic energy production. An improvement in VO2max is important for endurance athletes because it means more oxygen is available to working muscles for energy production during exercise.
  • Lactate Threshold – Lactate threshold represents the point at which the athlete’s body requires a greater contribution from the glycolysis energy system (anaerobic system) and a smaller contribution from the oxidative phosphorylation energy system (aerobic system). At this point, lactate production exceeds the lactate removal rate and blood lactate levels increase. One of the primary goals of endurance training should be to increase an athlete’s lactate threshold.
  • Power – Power is primarily a cycling metric. It is simply defined as the rate of doing work, where work is equal to force times distance. Power is measured via a power meter on a bike. See How to Conduct a Functional Threshold Power test for more information on power-based training.
  • Rate of Perceived Effort – Rate of Perceived Effort, or RPE, is a psychophysiological scale, meaning that it calls on the mind and body to rate one’s perception of effort. The traditional scale called the Borg Scale is based on a scale of 6-20, where a score of 6 is equivalent of no exertion and a score of 20 is equivalent of maximum exertion. Many coaches and trainers, myself included, will use a scale of 1-10 for easier understanding by the athlete/client.

Above are several common exercise physiology and training metrics terminology that are often thrown around by athletes, coaches, and endurance sport authors. Of course, there are many more that we could discuss.

~ Happy Training! 

Book Review: Run or Die

I have major “reader ADD.” I have a huge stack of books sitting on my bed stand waiting to be cracked open for the first time or partially read and just waiting to be loved again. I will start a book and then hear about a better book and read that all while my “to read” books pile up. I’ve made a good dent in my pile this summer (ok, maybe only in the past couple of weeks) and then I go to the book store or Amazon and buy more books. I think I seriously have a problem!

Source: Amazon

Source: Amazon

Anyway, while browsing some of my favorite blogs I found a book review on Kilian Jornet’s Run or Die book that caught my attention. I quickly added the book to my ever-growing “to read” list I keep in my purse, even though I had no idea who the heck Kilian Jornet was. I just knew he was an ultra-runner from Spain who is only 25 years old. Interesting. Last week I had some time to kill before meeting up with a friend so I went to Books-A-Million. I like Books-A-Million, but can I say that I totally miss Borders?! My first stop in any bookstore is always the sports and fitness section to see what the store has on triathlon and exercise physiology books. And then I head over to the science section. Yes, I’m a proud science nerd! Surprisingly, BAM had Jornet’s Book so I picked it up.

I finished the book in a couple of days. It’s short (less than 200 pages) and is a quick and fast read. The book was originally written in Spanish and then translated into English, which at times makes the writing a like awkward at times. Now, who is Kilian Jornet you may ask. Good question! He is a 25-year-old world champion ultrarunner and ski mountaineer who grew up in the Catalan Pyrenees. He began his skiing, running, and mountaineering career at a very young age. By age 5 he had completed the ascent of Aneto, the Pyrenees’ highest peak with his family. Now, that is pretty awesome if you ask me!

He has won the Ultra-Trail du Mont-Blanc, a 168K trail race around Mont-Blanc with over 9600 meters of climbing that must be completed under 46 hours. He has won this three times. He also won the 2011 Western States 100 in California. He has also set the speed record on Mount Kilimanjaro, Africa’s highest peak and my number one bucket list item! I’m a bit jealous!

As you can see the kid is pretty spectacular and an amazing athlete. With that part set aside, what I really enjoyed about his book is his maturity and worldly view of his life and what he does. His descriptions of the scenery he sees on his runs and his feelings are very real and keeps you turning the page for more. Through his story you can tell that some of his biggest life lessons have come from running. Clearly this kid is very well-disciplined. Heck, he goes out a runs for 5+ hours for fun!

One section in the book was about Alba, a girl he met on a bus back to his hometown who he fell in love with. From his writing and her mention in the book you can tell that she profound effect on his life. One of my favorite quotes of the book comes from his questioning himself as a person after he and Alba break-up: “It motivated me to find strength and inspiration from those around me, because the winner isn’t the strongest, but rather the one who truly enjoys what he is doing” (page 124).

Chapter 9 entitled “what I think about when I think about running” is the chapter that really hit home for me. As a long-course triathlete it is often hard for my friends and family to understand why I think swimming, biking, and running hours on end each day is fun. Kilian hits home exactly my stance on the issue:

“When thoughts sail through my head and can find no way out, I always go for a run to free up my mind. I find that then I can see everything more clearly, and that my problems are put into perspective. Running is the best way for me to disconnect from routine and to find the solutions to my problems, which I struggle to see even though they are often staring me right in the face” (page 173).

I tend to solve all my problems while I’m either running or biking. I often train alone because I need that time to sort out life’s problems. I have solved many of the world’s problems in my head while running, now just to make them tangible… 

In a nutshell, I recommend this book. It’s a quick and fun read. Kilian is very wise and mature for his young age. He has done some truly remarkable things thus far and I’m sure he is on the path for more greatest in the sports of running and skiing. And perhaps he’ll let me crew for him when he makes a speed attempt on Mount Aconcagua!

~ Happy Training!

Muscle Imbalances – What You Need to Know!


In order to fully understand muscle imbalances, let’s first look at normal muscle function. There are three types of muscles in the body: smooth, cardiac, and skeletal. We, of course, are investigating skeletal muscles – or the muscles that move our bodies through the swim, bike, run movement patterns. Normal muscle activation is a combination of contraction and relaxation of muscle fibers. The technical terms are called facilitation (contraction) and inhibition (relaxation). When muscles contract, they get tighter and do more work. When muscles relax, they do less work and allow their opposite muscles to contract better. Muscles in the body generally work in pairs.

Let’s use the examples of your biceps and triceps. Let’s imagine that you are sitting on a bench with a dumbbell in your right hand about to do a set of biceps curls. What happens when you move your right hand towards your shoulder? Place your left hand over your right bicep. In the rest position your biceps is pretty relaxed. The same with your triceps. Neither should feel tight or loose. Just relaxed. Now move that dumbbell up towards your shoulder and do a biceps curl. Now feel that biceps in the top hand position. Feels pretty tight now doesn’t it? The biceps muscle is contracting to pull the dumbbell towards your shoulder. Now feel the triceps. The triceps muscle should feel loose because it must relax in order for the biceps to contract. Now lower the dumbbell to the start position. The biceps muscle should be relaxed (loose) and the triceps contracted (tight). The same thing happens as you are running. As you lift your leg to propel yourself forward, your quadriceps (front of tight muscles) must contract to lift your knee forward and the hamstrings (back of thigh muscles) must relax. When the muscles are balanced in the body, they have the right combination of inhibition and facilitation during movement.

Wikimedia Commons

Wikimedia Commons

If muscles lack the right combination of inhibition and facilitation during movement muscle imbalances can occur. Muscle imbalances may lead to injuries, biomechanical inefficiencies, and wasted efforts. Muscle imbalances can also occur due to poor static posture, joint dysfunction, and myofascial adhesions (think “knot” in muscle). These altered length-tension relationships between muscles may lead to altered muscle recruitment patterns (altered force-couple relationships). This is caused by altered reciprocal inhibition. Altered reciprocal inhibition, defined by NASM, is the process by which a tight muscle (short, overactive, myofascial adhesions) causes decreased neural drive, and therefore optimal recruitment of its functional antagonist.

Let’s look at an example of this. A majority of people work 9-5 desk jobs in front of a computer. Thus they tend to have tight hip flexors, or iliopsoas muscles. Tight psoas muscles decrease the neural drive and therefore the optimal recruitment of gluteus maximus (your butt muscles). The gluteus maximus muscles are the prime movers for hip extension and an important muscle in running. According to a 2006 study in The Journal of Experimental Biology, the gluteus maximus works primarily to keep the torso upright during movement and it is involved in decelerating the swing leg as it hits the pavement. Since the glute is a hip extender muscle, it also functions to extend your hip-joint as your foot pushes off the ground to propel your body forward. Weaknesses in the gluteus maximus can lead to compensation and substitution by the synergists (hamstrings) and stabilizers (erector spinae). This can ultimately lead to potential hamstring strains and lower back pain.

According to one study, over the course of any given year approximately two-thirds of runners will have at least had one injury that has caused an interruption to their training. For those training for marathons, the rate as been recorded up to 90% of runners. The most common running injury involves the knee. The most common running related knee problems are patellofemoral pain syndrome, Iliotibial band (IT-Band) sydrome, tibal stress syndrome (spin splits), and plantar fasciitis. Guess what? These common running injuries are overuse injuries generally caused by muscle imbalances!

Some researchers and sports medicine professionals have argued that triathlon, as a multisport event, causes less overuse injuries than single sports, because of the more even distribution of loads over the body’s muscluar system. However, triathletes still suffer from a high degree of overuse injuries. One of the most common is actually lower back pain. Triathletes tend to be over-developed in larger muscle groups, such as the quadriceps, hamstrings, and shoulders. Triathletes tend to be weak in the smaller stability muscles, such as the lower back, core, adductors, and abductors. Again, these muscle imbalances are caused by movements that we do in each sport. For example, many triathletes, especially if they come from a cycling background, will be overdeveloped in the quadriceps region, but have these tiny, underactive hamstrings. This is a muscle imbalance caused by cycling. Runners are very weak in the hip stability muscles, such as the gluteus medius, tensor fascia latae (TFL), and adductor complex, which leads to weak lumbo-pelvic stability and the potential development of common running injuries. The sport of triathlon is conducted in one plane of motion – the sagittal plane. We rarely move in the frontal and transverse planes. Many of the hip stability muscles are targeted by movements conducted in the frontal and/or transverse planes.

Wikimedia Commons

Wikimedia Commons

Muscles can be divided into two types: postural and phasic. Postural muscles are used for standing and walking; whereas, phasic muscles are used for running. During the gait cycling of running, there is a double-float phase during which both legs are suspended in the air – one at the beginning and one at the end of the swing phase. Running biomechanics requires efficient firing patterns from the postural muscles while the phasic muscles do the actual work of propelling the body forward. Since the postural muscles are constantly be activated in the body to fight the forces of gravity, these muscles have a tendency to shorten and become tight. The postural muscles that tend to become chronically tight in runners are: gastroc-soleus, rectus femoris, ilipsoas, tensor fascia lata, hamstrings, adductors, quadratus lumborum, piriformis, and satorius. Phasic muscles typically may remain in an elongated or weak state. Common phasic muscle that have a tendency to be weak or become inhibited in runners are: the tibialis anterior, vastus medialis, long thigh adductors, and the gluteus maximus, medius, and minimus.

So, key points from this post:

  • Muscle imbalances are caused by the lack of the right combination of contraction and relaxation of paired muscles
  • Common triathlon and running injuries are generally caused by muscle imbalances, mainly in the lumbo-pelvic region
  • Postural muscles tend to become short and tight; whereas phasic muscles tend to become weak and inhibited
  • Stretch your psoas muscles! 🙂

Now, how do you identify muscle imbalances? Well, I did a post a while ago on why functional movement screens are important. Go read that! Or go see a sports medicine professional, such as a chiropractor or physical therapist. This is especially important if you are dealing with a common running-related injury. Then find yourself a good personal trainer to help set you up on a good strengthening routine to correct those imbalances. Remember, I am certified to help you correct muscle imbalances. Of course, you should always seek permission from your doctor before starting any new exercise routines. Stay tuned next week on some good hip stretching and strengthening exercises to help you prevent those pesky running injuries.

~ Happy Training!

PS – Feel free to contact me with any questions at


1. Maffetone P. The Big Book of Endurance Training and Racing. New York, NY: Skyhorse Publishing. 2010.

2. Clark MA, Lucett SC. NASM Essentials of Corrective Exercise Training. New York, NY: Wolters Kluwer Health. 2011.

3. Liebermna DE et al. The human gluteus maximus and its role in running. J Exp Biol. 2006; 209: 2143-55.

4. Manninen JSO, Kallinen M. Low back pain and other overuse injuries in a group of Japanese triathletes. BR J Sports Med. 1996;30: 134-139.

5. Fredericson M, Moore T. Muscular balance, core stability, and injury prevention for middle – and long-distance runners. Phys Med Rehabil Clin N Am. 2005;16: 669-689.

USAT Triathlon Coaching Level I Clinic

Ok, so this post is a little late. Like 6 weeks late. But, on the good news… I’m officially a certified USAT Level I Triathlon Coach! Yay!

It's Official!

It’s Official!

Back in April Jen and I took a road trip down to Short Hills, New Jersey for the two-day clinic. I’ll be completely honest, I was dreading the New Jersey location. I was thinking it was going to be in a super sketchy part of NJ and all the people living there were going to be right out of Jersey Shore. My worst nightmare! I was pleasantly surprised to find out that Short Hills is an absolutely gorgeous part of NJ! The streets were lined with sidewalks and trees. The houses were cute and nice. And holy heck the town was hilly! I always thought that NJ was pretty flat, but I guess not. Hence the town name of Short Hills. However, those hills were anything but short!

Day one of the clinic included lectures by all three of our presenters: Jesse Kropelnicki of QT2 Systems, John Petrush of Bay Shore Swim, and Shelly O’Brien of Icon One Multisport. The morning started off with two lectures on exercise physiology and nutrition by Jesse. I was super pumped when I first saw that Jesse was going to be a presenter at our clinic. He is one of the top coaches in the country and is someone who I highly look up too. I must admit that I was a wee bit disappointed with his lectures. Not because they were boring or bad, but because both topics were review for me.

Jesse Kropelnicki

Jesse Kropelnicki

After lunch Joe came in and discussed strength training and cycling skills and training with us. Joe is from Long Island and was your stereotypical Long Islander. He was very interesting to listen to. He was funny, but also very opinionated. His lectures were good. However, I disagreed with him on his view of strength training. He told us up front that we were completely welcomed to disagree with him on the topic since strength training for triathletes is still a rather controversial topic. His view was that “if it ain’t broke than don’t fix it.” He generally prefers not doing traditional strength training with his athletes unless they are injured. His approach with strength training is to do it within the swim, bike, run realm. For example, run or bike hill repeats to build leg strength. I can see where he is coming from. I agree that some strength building within each discipline is important, such as running hill repeats. However, I believe that traditional strength training should be part of an triathlete (or any endurance athlete)’s training plan. I don’t mean they need to do traditional body building style training. That would actually not be a favorable way to train. Can you see Arnold doing an Ironman? That poor carbon fiber bike doesn’t have a chance…

Joe Petrush

Joe Petrush

I much prefer functional training with bodyweight and TRX. Anyway, now that I have left on my tangent I will get back on track! The last lecture of the day was on swim skills and training by Shelly. Shelly is an amazing person to listen to and just a wealth of information. She was by far my favorite person to listen to (which is a good thing because she did all the lectures on the second day). Shelly made each lecture more interactive, which was awesome because sitting in a chair for 10+ hours a day is not my thing. I couldn’t sit for much of the time and kept shifting about in my chair. Secretly, I think all that sitting played a role in my IT-band/Knee/Hip issues.

After the first day Jen and I headed back to our hotel. I headed out for a quick 50 minute run. It was a bit drizzly out, but quite humid. The main roads in the area were busy and we found out quickly that New Jersey drivers were crazy so I headed out to run around the neighborhoods. The neighborhoods were cute and situated on some massively steep hills. Holy cow was my pace slow, but it was fun to run, essentially, hill repeats. After my run we hit up the Cheesecake Factory. It was my first time! Yum yum yum! I had the salmon with mashed potatoes and asparagus. And of course, Jen and I split some Cheesecake, cause ya know it was my first time and all…

Shelly O'Brien

Shelly O’Brien

The second day was another very long day of sitting. On the second day we discussed running, sports psychology and mental training, and how to build training plans. Unfortunately, most of the time Shelly ran out of time during each lecture because she just had so much to tell us. She gave us a bunch of awesome drill ideas for running and swimming. Some of which I have been trying on my own since then and also have incorporated some of them into my own clients training plans.

Everyone at the clinic came from various backgrounds and reasons why they were attending. Some were already experienced coaches and some are complete newbies. We had a few sports doctors and physical therapists too. It was fun to talk to different people and hear their thoughts on the sport and training. USAT recently changed their criteria to get into the clinic. It used to be the first 40 people to register would get into the clinic. Now you have to apply. Over 70 people applied for our clinic and they accepted 40 of us. I’m glad I made the cut!

Here are some interesting tidbits I learned while at the clinic from the various presenters:

  • There is generally a 4-16 beat difference in heart rate between running and biking (average is about 10 beats)
  • It usually takes about 20-30 minutes for the heart rate to settle down after the swim
  • Heart rate is important for training and power meters are important for racing
  • Train movements not muscles (aka functional training!)
  • When working with youth athletes (under age 10) work anaerobic first then aerobic capacity
  • Develop speed and endurance together
  • Develop various skill sets in each sport (i.e. drills)
  • There is no such thing as a good bike and a bad run in triathlon, especially long course!

My favorite is the last bullet point. It is the one that I have been learning over the past year with my coach. If you go out too fast and hard on the bike and burn all your matches then your legs and body are toast for the run. Words of wisdom right there kids!

Crossing the GW Bridge in NYC

Crossing the GW Bridge in NYC

~ Happy Training!

PS – If you’re looking for a triathlon coach then I hope you will consider me! 🙂

Are Elite Athletes Born or Trained?

A good friend recently turned me about the The Science of Sport blog and, of course, being the science dork I am, really enjoy it. On Tuesday they (Dr. Ross Tucker and Dr. Jonathan Dugas) discussed the polarization of the debate on whether elite athletes are born or trained. I was intrigued by the discussion because a) I’m an athlete, b) I am interested in exercise physiology, and c) I have a background in genetics and molecular biology. Since the article peaked my interested I decided to do some research into the debate.

So… are elite athletes (or even top age group athletes) born or trained?

The 10,000 Hour Theory

Sports performance results from a combination of numerous factors which interact with each other in a complex and poorly understood manner to mold a talented athlete into a champion. Within the field of sports science it is believed that elite performance is the result of both training and genetic factors. To what extend each component plays is the question that many sports scientists have tried to answer.

The “born versus bred” debate dates back to the 1800s, but more recently has been played out in the popular literature. In 1869, Sir Francis Galton proposed in his Galtonian Model that “practice and training would lead to improvements in performance, but that a ceiling existed for each person, influenced by heritable characteristics” (1). However, K. Anders Ericsson and his Colleagues have suggested that performance is constrained by engagement in deliberate practice and training during optimal periods of development (1). According to Ericsson’s model “practice is both necessary and sufficient for the attainment of deliberate performance, and is effective because it ‘selectively activates dormant genes that are contained within all healthy indovoduals’ DNA'” (1). A lot of people are familiar with Ericsson’s work because it is often referred to as the 10,000 hour rule.

Ericsson’s model proposes that “a specific volume of 10,000 hours of training must be accumulated over a period of approximately 10 years of structured training and involvement in an activity in order to achieve expert level” (1). His theory originated from a study conducted on violinists in Berlin. He found that the subjectively judged skill level of violinists were associated with accumulated training time over the first 20 years of their lives. The best performers had accumulated over 10,000 hours of training by the age of 20. Those who were judged to be good or average had accumulated about 7800 and 4600 hours, respectively. Ericsson concluded there was a ” complete correspondence between the skill level of the group and their average accumulation of practice time alone with the violin” (1). However, one crucial mistake Ericsson made was presenting no measures of variance in the results of the study. No standard deviations (SD) or ranges were provided and thus it is unclear whether the association between training and performance abilities applies to every individual in the study.

A similar study was conducted in chess players. Gobet and Campitelli found in a study of 104 chess players, that the accumulated training time to reach master level was 11,053 hours (+/- 5538 hours). This result is in close agreement with the violin study, but the study shows that there is enormous differences that exist between individuals that is indicated by the SD. Studies of sport have shown that elite athletes rarely accumulate 10,000 hours before reaching elite status. For example, one study found that 28% of elite Australian athletes reached elite status within 4 years of taking up the sport for the first time (1). It has been concluded that talent transfer based on innate abilities and ability and fitness developed through other sports, can be used to accelerate the process of becoming an elite athlete within a short time frame, which explains why elite athletes often perform far less than 10,000 hours of deliberate practice.

The Genetic Influence – Thanks Mom and Dad

DNA is the building block of all life forms (unless you’re an RNA virus). DNA carries the genetic information for all development and functions in organisms. At the molecular level, numerous physiological and biochemical systems and pathways must interact and function optimally to enable elite performance. These processes occur simultaneously within the musculoskeletal, cardiovasular, central nervous and respiratory systems. When considered on their own, each biological system is complex, consisting of different cell types, proteins, and numerous other macromolecules. Multiple types of genes throughout the entire human genome determine the genetic blueprint for each individual biological system. With the great complexity in the human body, it is highly unlikely that a singular or even a few specific genes are associated with elite athletic performance.

Elite performance is a polygenic trait, meaning that it is determined by multiple genes. There are numerous specific genes that studies have found to affect athletic performance to a certain extent. There are several genes that play a role in determining four intrinsic traits that are known to contribute to elite performance phenotypes – sex, height, skeletal muscle properties and VO2max. Biological sex is a key predictor of absolute levels of performance. An analysis of world record performances on the track and in road running events, ranging from 100 meters to ultramarathons, shows that the best males out perform the best females between 9% and 14% (1). Unlike sex, height is determined by both genetic and environmental factors (i.e. nutrition). Many studies have indicated that height is highly heritable with 80% of its variance controlled by multiple genes (1). The influence of height on sports performance is dependent upon sport (i.e. being tall is advantageous for basketball, whereas it would be deleterious for endurance running).

VO2max is a very interesting intrinsic factor because it is about 50% hereditary and 50% trained. VO2max is the maximum capacity of an individual’s body to transport and use oxygen during incremental exercise, which reflects the overall physical fitness of the individual. Large cross-sectional studies (i.e. the Heritage studies, the Dose Response to Exercise in Women (DREW) study, and SSTRIDE studies) have found an average training-induced improvement in VO2 max of 15.2 (+/- 9.7%), but the interindividual differences are significant (1). For example, based upon the studies, approximately one in seven individuals (14%) improved VO2max by less than 200 ml/min (less than 8% improvement from baseline). In comparison, 8% of the study population improved by more than 700 ml/min, which is a 28% improvement from baseline (1). Both genetic and environmental factors have been reported to determine VO2max in the untrained state and in response to training. The Heritage study showed that the variance of VO2max among families is 2.7 times higher than the VO2max variance calculated within each family (2). The correlation between parents and offspring indicated a 52% inheritance component (2). Genomic scans have found that 21 SNPs (single nucleotide polymorphism) are linked to 49% of trainability in VO2max (1). Individuals who carried nine or fewer of the 21 SNPs were found to have improved their VO2max by less than 221 ml/min, whereas those who carried 19 or more of the SNPs had improved by an average of 604 ml/min (1).

By the end of 2005, 165 autosomal (not a sex chromosome) genes and five genes on the X chromosome have been identified as having an association or linkage to performance. Seventeen mitochondrial genes have also been identified. Mitochondrial genes originate from DNA located in the mitochrondria of cells. Mitochondrial genes are solely inherited from the mother because the mitochrondria in the sperm cell is normally destroyed by the egg cell during fertilization. Studies have indicated that there is a significant association for VO2max between children and their mothers, but not between children and their fathers (2). Individuals with mutations in mitochrondria DNA generally show exercise intolerance, muscle weakness, and increased production of lactic acid (2).

One of the most studied genetic markers in the human performance field is an insertion/deletion (I/D)mutation in the gene encoding for angiotensin-converting enzyme (ACE) on chromosome 17 (2). ACE influences circulatory homeostasis (ability to stay the same) through the breakdown of vasodilator (widening of blood vessels) bradykinin and creation of the vasopressor, angiotensin II (a peptide hormone that causes vasoconstriction which results in an increase of blood pressure) (2). The I allele has been associated with fatigue resistance in skeletal muscles and with endurance performance. Studies have found that the I allele is found at excess frequencies among elite long-distance runners, rowers, and mountaineers able to climb peaks higher than 7000 meters without supplemental oxygen (2). The D allele has been associated with sprinting and power-based performance (2). Another study found that the I/D alleles are also related with type and the efficiency of skeletal muscle fibers (2). There is an associated between the ACE*II genotype and an increased percentage of type I skeletal muscle fibers (slow-twitch fibers) compared with the DD genotype (2).


No person has been able to ascertain the exact relative contribution genetics or training to elite human performance in sports, and it is generally recognized that both play a role in determining the elite potential in an individual. It is silly to negate the role genetics play in the development of elite performance in athletics. Our genetic codes determine the development and function of every molecule in our bodies. Scientific data on other determinants of elite performance, such as metabolic efficiency, fuel-oxidation rates, muscle-fiber contractility, and even motivation for exercise is currently limited, but it seems reasonable to suggest that the above determinants will also be influenced by genetics. However, science and common sense has also indicated that training plays a major role in elite performance. Tucker and Collins propose a model where training is defined as the realization of genetic potential (1).

Personally, I agree with Tucker and Collins. Training maximizes the likelihood of obtaining a specific performance level with a genetically controlled “ceiling.” For example, you might be a standout basketball player on your high school team, but if you’re only 5’4″ then your chances of playing in the NBA are probably very slim. You can train all you want to improve your skills and fitness, but you cannot change your genetics to grow taller. In 2003, the Human Genome was successfully sequenced. Scientists across the globe are now just starting to identify the function and role each of the approximately 23,000 genes in the human genome. Determining the function and role of genes in the human body is extremely complex and will likely take decades to complete and fully understand. The role of genetics in human performance exists and will not likely be disputed as is the role of training. How much each plays in determining the performance level of an individual is really the question scientists are trying to answer. The question of determining whether elite athletes are born or trained is really the old “nature vs. nurture” question in disguise. Only time will tell.


  1. Tucker R, Collins M. What makes champions? A review of the relative contribution of genes and training to sporting success. Br J Sports Med. 2012; 46: 555-561.
  2. Calo CM, Vona G. Gene polymorphisms and elite athletic performance. Journal of Anthropological Sciences. 2008; 86: 113-131.