When it comes to an individuals athletic ability I’m afraid to say that their are a whole lot of genetic and congenital (Traits from Birth) factors involved.
Cardiac capacity (The hearts ability to deliver enough oxygen via the bloodstream to the working muscles) is largely determined by genetics, just like an individuals lung capacity, natural strength levels, muscle size/composition and flexibility levels.
Even Anthropometry (Measurements and proportions of the human body) can have effects on an individuals athletic capability – Influencing leverage efficiency in the mechanical expression of force production – Skeletal size will often determine the sports in which an individual may excel. (Long Tibias and shorter Femurs are associated with sprinting efficiency)
Another major factor is Muscle Composition – The ratios of Type 1 and 2 muscle fibres will have huge effects on determining what sports an individual may be suited to – Individuals with a higher % of Type 1 fibres will be more suited to sports which require more endurance, whereas an individual with a higher % of Type 2 muscle fibres will be more suited to sports which involve shorter bursts of energy.
- Type 1 (Slow Twitch Fibres) – More efficient at using oxygen to generate fuel (known as ATP – Adenosine Triphosphate) for continuous, extended muscle contractions over a long time. They fire more slowly than fast twitch fibres and can go for a long time before they fatigue – Marathon Runners etc.
- Type 2 (Fast Twitch Fibres) – Use anaerobic metabolism (without oxygen) to create fuel, they are much better at generating short bursts of strength or speed than slow twitch fibres. However, they fatigue faster. Fast twitch fibre generally produce the same amount of force per contraction as slow muscles, but they get their name because they are able to fire more rapidly – Sprinters etc.