Solely doing this kind of exercise can also lead to the unused fast-twitch fibres fading and sometimes even dying off.
Loss of muscle due to age can also be due to fading of the fast-twitch fibres, so it is pertinent for anyone 30 or over – from which age you can begin to lose muscle mass – to engage in a regular strength training routine in order to moderately build the fast-twitch fibres (though 5 to 10