Knowing your Genetic Markers can help you in the pursuit of a better workout
To get the best out of a workout there are many factors that play a vital role in the pursuit of optimal results, these can be intrinsic (genetic) and extrinsic (environmental). While some of these can be trained or taught (biomechanical and technical) others are beyond the control of the individual or coach (genetics)..
It is widely accepted that a superior ability to perform physical activities is associated with certain genetic traits. Genetics plays a massive role in terms of anthropometric, cardiovascular, and muscular characteristics for the adaptation to physical training.
In the weight room some individuals make superior gains in strength and size (responsive individuals) while others obtain inferior results (poor responsiveness) when following an identical strength program. Whether you are training for a marathon, triathlon, or your first body building competition, knowing your genetic markers and understanding their response to different training stimuli will better allow you to alter your training methodologies to take advantage of your individual traits.
For an athlete to be successful in power and sprint performance their muscles must produce force at a high velocity. The ACTN3 R allele and RR genotype have been found to be associated with top-level power-oriented athletic performance in a broad variety of ethnic groups. Moran et al. reported that men with the R allele (RR or RX) had better sprinting ability than those with the XX genotype. The ACTN3/RR allele is expressed in fast type IIb fibre types and therefore associated with elite power and sprint performance.
It is estimated that 19% of individuals, or one billion people worldwide, are functionally redundant (ACTN3/XX) and their bodies create more ACTN2. These individuals do not possess the explosive qualities as their alpha-actin-3 counterparts and the shift toward a slow oxidative phenotype leaving these individuals 'pre-trained' for endurance training.
Naoki et. al conducted a study to measure anaerobic performance on Japanese male athletes using a Wingate test. It was found that the ACTN3 R allele was associated with relative peak power, which suggests that athletes with the R allele may possess a higher-capacity phosphagen system. Massidda et al. also reported that the ACTN3 R577X genotype accounted for 8.0% of the variation in squat-jump performance in elite soccer players.
People with the ACTN3 R allele (RR and RX) have an advantage over XX individuals in terms of power-oriented performance and therefore should utilise their time in the gym performing workouts of short duration and high intensity, resulting in muscle hypertrophy, with increased fibre cross-sectional area and an increased ability to generate force.
Individuals with the XX genotype, being completely deficient in the a-actinin-3 protein, exhibit inferior skeletal muscle function in terms of force generation from contraction and have a poor ability to recover from high-intensity intermittent exercise as they exhibit higher CK activities, a-actin concentrations, and levels of cortisol. It would be advised for someone who is ACTN3 deficient to hang up their running spikes and change their workout that better suits an endurance event such as an Ultra marathon. Identifying their markers will allow them to utilise their time spent training as they must undergo an exercise program with increased length and reduced intensity, inducing a shift in skeletal muscle metabolism toward a more oxidative form.
Numerous other gene polymorphisms have been identified, which relate to differences in the exercise phenotype and their trainability. Studies have shown the association of the ACE I allele among athletes who perform long-distance events and an increase in the frequency of the I allele as the distance of the event increases. Myerson and colleagues found a significantly greater frequency of the D allele among who compete in shorter-distance events such as Olympic sprinters running 200 m or less.
The transcription factor hypoxia-inducible factor 1 (HIF1) is one of the key regulators of cellular metabolism and is a useful genetic marker in rowing as it regulates several of the major physiological changes in the skeletal muscle's response to physical training (mitochondrial volume, increased reliance on fatty acid metabolism for energy, decreased lactate production)
A genetic profiling test can provide useful information (e.g., talent selection and genotype-based customization for training) for athletes. Once an individual knows their genotype it only then becomes evident that there is a functional trade off between the type of workout they must follow in order to excel in their chosen activity.