The biceps are approximately 60% fast twitch muscle fibers and 40% slow twitch muscle fibers. This means that fast twitch muscle fibers respond better to faster, heavier movements1. Therefore, you are going to want to make sure you are lifting in the 6-12 repetition range for about half of your lifts.

to wait until the problem comes up in trying to resolve it rather than placing solutions for something that is not currently an issue. to deal with something when the time is right.

Fast-twitch type II muscle fibers are further divided into Type IIx and Type IIa. Typically, these have lower concentrations of mitochondria, myoglobin, and capillaries compared to our slow-twitch fibers, which means they are quicker to fatigue (1,2).

The primary metabolic pathway used by a muscle fiber determines whether the fiber is classified as oxidative or glycolytic. If a fiber primarily produces ATP through aerobic pathways it is oxidative. More ATP can be produced during each metabolic cycle, making the fiber more resistant to fatigue.

Most people are born with relatively equal amounts of fast twitch and slow twitch muscle fibres, but this is not universally true. Some people are born with a far greater amount of one type. It stands to reason, therefore, that those people would have an advantage in certain types of sports as well.

Studies show that athleticism may be in the genes, but there are also other external factors that may impact a child’s athletic success. Watching your child grow up comes with the joys of seeing their looks and personality develop over time, as well as their skills (or lack thereof).

Under normal circumstances our fast-twitch muscle fibers become smaller (atrophy), and may even disappear in more advanced years.

“But there is no single gene that accounts for speed and power, or for sprinting. From what we know so far it appears to be a really complex interaction of lots of genes. So it’s impossible to say there’s a west African genotype for sprinting, or an east African genotype for endurance running. Genes only play a part.”

Neither! A child’s athletic ability will come from training, and personal health care, and a personal want to achieve in athletics. Two successful athletes having a child, does not mean their child automatically is an athlete, or will have any athletic abilities.

Grand Valley State University researchers found that exceptional speed prior to formal training is a prerequisite for becoming a world-class sprinter. The findings are published in the online journal PeerJ.