7.1) Power and Endurance
In Power and Endurance, your genetic information helps you understand which types of exercise most naturally suit your body.
Power activities involve high-intensity, interval training, whereas endurance activities involve moderate-intensity for a moderate to long duration. Power activities include sprinting, weight training, speed and power sessions, and sports specific drills. Endurance activities include long distance running, cycling, hiking, swimming, triathlon, and some field sports.
People are naturally drawn to the activities that feel best for their bodies and most of us have a mix of both power and endurance capability. You may already know intuitively and through experience which activities are best suited for your genetics. By choosing activities in which you are naturally suited, you may find you reach your fitness goals more easily.
However, genetic potential is just that. You have potential to do well in all aspects of exercise. In the end, do what you enjoy. Maintain a well-rounded exercise plan regardless of your genetic type. Simply be conscious of areas where you may have some potential limitations to ensure you exercise in a way that is healthy and supportive of your body.
Figure 7-1 The genetic inheritance of endurance and muscle strength is estimated at 40-70% for VO2 max (peak oxygen uptake) and cardiac mass and structure, and 30-90% for anaerobic power (peak power output) and capacity. https://link.springer.com/article/10.2165/11650560-000000000-00000#Abs1
7.1.1 Endurance Activity
How suited you are for endurance activities
Endurance activity is the ability to do light-to-moderate intensity exercise for extended periods of time. During endurance exercise, your muscles sustain repeated muscle contractions with relatively low resistance and constant heart rate. Having slow-twitch muscle fibers helps people excel at endurance sports. Endurance activity relies on the aerobic system which requires a steady supply of oxygen to generate energy. It burns about 25% muscle and 75% fat. It also increases muscle and joint flexibility, making you less susceptible to injury. Endurance activities improve the capacity of the lungs and have a positive impact on the cardiovascular and circulatory system.
If you are predisposed to endurance activity, your body will tend to perform better doing exercise such as long distance running, cycling, hiking, swimming, rowing and cross-country skiing.
Variations in these genes may lead to trouble maintaining power for extended periods of time. Other effects include increased thirst sensation, desire for salt, sodium retention, water retention and potassium excretion, and decreased urine volume. But it’s not all bad. Some variations have been linked to positive effects, such as keeping blood pressure low and having fast twitch muscles which are important in power and sprint activities.
Even if you have good endurance results you should consult all of your other test areas, including tendon and ligament strength, blood pressure regulation etc. when building a fitness routine.
If you are predisposed to endurance activity, you may want to consider the following to enhance your fitness:
- Consider controlled exercises such as cycling, swimming, jogging, rowing and yoga.
- Engage in slower, more controlled repetitions in weight training, as your fast twitch muscles may be slower to react. Do longer sets, with lighter weights.
- Consider supplements that support endurance athletes such as: calcium, iron, magnesium, potassium, selenium, sodium, zinc, vitamin E, protein and glutamine.
Some examples of genes that have been associated with endurance activity are:
ACE: Activates electrolyte balance and systemic blood pressure; stimulates heart muscle enlargement; influences your cardiovascular health. Helps provide optimal muscle efficiency in sports.
ADRB2: Plays an important role in the regulation of the cardiac, vascular, pulmonary, endocrine, and central nervous systems. Associated with elite endurance sports performance.
GABPB1: Involved in the control of mitochondrial function. Mitochondrial produce the energy currency of the cell and regulate cellular metabolism. Variation is associated with positive effects on endurance capacity and elite endurance performance.
GALNTL6: Associated with world-class endurance athletes. Expressed in the testes, brain, and skeletal muscle.
HFE: Regulates iron absorption and storage, which can affect the production of red blood cells. Variation is association with iron overload and an advantage in endurance performance.
HIF1A: Activates genes involved in energy metabolism, angiogenesis, apoptosis, oxygen delivery, and metabolic adaptation to hypoxia. The common genotype is associated with higher changes in VO2 max following training. Whereas variation is associated with an increased proportion of fast-twitch muscle fibers and improved glucose metabolism including a lower risk of type 2 diabetes.
NFIA: Associated with aerobic performance, the efficiency of the body’s cardiovascular system in absorbing and transporting oxygen.
PPARA: Mediates fatty acid oxidation, lipid metabolism and the production of glucose for energy consumption. Expression of PPARA is higher in type I (slow-twitch) than in type II (fast-twitch) muscle fibers.
RPLP1: Plays an important role in the elongation step of protein synthesis.
TSSC1: One of several tumor-suppressing sub transferable fragments, an important tumor-suppressor gene region. Variation is associated with decreased odds of being an endurance athlete.
VEGF: Involved in the formation of the circulatory system and the growth of blood vessels from pre-existing vasculature. Variation is associated with an advantage in endurance performance and greater increase in the maximal oxygen uptake in response to aerobic exercise.
7.1.2 Power and Sprint Activity
How suited you are for power, sprint and high-intensity activities
Power and sprint activity require the ability to perform at a high intensity for short periods of time. It uses fast twitch muscle fibers to support bursts of power. It also uses the anaerobic system that relies on energy producing processes that don’t require oxygen to generate energy. Anaerobic training leads to greater performance in short duration, high-intensity activities, which last from seconds to around 2 minutes. It is used by athletes to promote strength, speed and power as well as muscle size and strength.
If you are predisposed to power, sprint and high intensity activities, your body will tend to perform better doing exercise such as weight training, sprinting, shot put, and jumping. High-intensity interval (HIT) becomes anaerobic when performed in excess of 90% maximum heart rate.
Individuals with variations in these genes may have a disadvantage when it comes to power and sprint activity and are more likely predisposed to endurance activities such as running and swimming.
If you are predisposed to power and sprint activities, you may want to consider the following to enhance your fitness:
- Focus more on sprint and power sports such as weight lifting or circuit training.
- Consider shorter cardio sessions or interval training.
- Engage in shorter, heavier sets for weight training to leverage your fast twitch muscles.
- Ensure adequate energy and protein intake which are important for increasing muscle mass.
- Consider supplements that support power and sprint athletes such as: beta-alanine and bicarbonate for longer sprints, creatine for muscle mass and strength, and fish oils and electrolytes for recovery.
Some examples of genes that have been associated with power, sprint and high-intensity activities are:
ACE: Activates electrolyte balance and systemic blood pressure. Helps provide optimal muscle efficiency in all sports. It is also a stimulator of heart muscle enlargement. Variation is associated with increased strength gain in response to exercise.
ACTN3: Encodes the protein that helps to anchor actin filaments in the muscle and is involved in fast-twitch movements. Plays a key role in power, sprint and endurance. Variation is associated with differences in fast-twitch muscle fiber.
ADRB3: Signals your adipose tissues to break down stored fats for consumption. Improves cardiac function, present in skeletal muscle. Variation is associated with elite athletic performance.
AGT: Encodes angiotensin proteins involved in constriction of blood vessels and increased blood pressure in response to exercise.
HIF1A: Activates genes involved in energy metabolism, angiogenesis, apoptosis, oxygen delivery, and metabolic adaptation to hypoxia. The common genotype is associated with higher changes in VO2 max following training. Whereas variation is associated with an increased proportion of fast-twitch muscle fibers and improved glucose metabolism including a lower risk of type 2 diabetes.
IL6: Regulates the body’s response to exercise, including processes that recruit stored energy in fat and muscle tissue for quick use to assist in muscle recovery processes.
NOS3: Regulates nitric oxide abundance, influencing muscle vascular tone and blood supply to working muscles.
VDR: Effects on bone and skeletal muscle biology.
Muscle fiber type
The ability to perform aerobic or anaerobic exercise varies widely among individuals, partially depending on their muscle-fiber composition. In untrained individuals, the proportion of slow-twitch (type I) fibers in the vastus lateralis muscle is typically around 50% (with a range from 5–90%). It has been suggested that the genetic, inherited, component for the observed variability in the proportion of type I fibers in human muscles is about 50%, and that the other 50% is influenced by environmental factors, for example training and use.
In humans, two genes encode for skeletal muscle α-actinins: ACTN2, which is expressed in all skeletal muscle fibers and ACTN3, whose expression is limited to fast-twitch muscle fibers. Interestingly, in European Caucasian populations ∼18% of individuals are fully ACTN3 protein deficient due to carrying two variant copies of the ACTN3 gene. It is believed that ACTN2 and ACTN3 are structurally similar enough that ACTN2 is able to compensate for the lack of ACTN3. This deficiency does not result in a disease or muscular functional impairment. However, there is a positive association between the presence of the fully functioning version of the gene and the capacity to perform high power muscle contractions. Individuals who are ACTN3 deficient can may need to work harder to achieve high power muscle contractions.
Simoneau, J.‐A., Bouchard, C. (1995). Genetic determinism of fiber type pro‐portion in human skeletal muscle. FASEB J. 9, 1091‐1095.
Vincent, Barbara, De Bock, Katrien, Ramaekers, Monique, Van den Eede, Els, Van Leemputte, Marc, Hespel, Peter, & Thomis, Martine A. (2007). ACTN3 (R577X) genotype is associated with fiber type distribution. Physiological Genomics, 32(1), 58-63.