Our range of strength starts from one factor and that is our genetics. Genetics control important traits such as the ratio of fast-twitch fibers, which facilitate a quick burst of power, and slow-twitch fibers which provide endurance and sustained force over time. It’s interesting to note that the more muscle mass someone possesses, the more glycine-rich fibres they have, resulting in greater strength and therefore more force they are able to exert; size as usual plays a role that is genetically determined.