So type IIb are both more powerful and stronger than type IIa in dynamic movements. However, my problem is - after a weights programme which increases the proportion of type IIa to IIb, in theory ballistic movements should then convert some of the IIa back to IIb - but, I am pretty sure this will not result in greater strength gains in the gym (assume weights in the gym are maintained) only power. Why? Or will it result in improved strength also?
Richard - You and your fast twitch fibres. Don’t worry about it, as Nike say, ‘Just do it’.
Ok David, I will just do it, but can you just answer me this.
Providing there are enough type IIa fibres in a muscle group, can they provide as much power as a muscle group with less total fibres but made up moreso of IIb?
In such a situation the greater neural firing rate of IIb would be irrelevant since IIa power would be as great due to the greater contractile tissue.
(Ignore the fact that the athlete would be heavier)
Just a little correction, type IIa will not convert to IIb. It will start to react more like Type IIb but will nevr become it. On the other end of the spectrum, if you were doing undurance work, Type IIa will start to react more like Type I muscle fibers. The percentage of the different muscle fiber are predetermined, one does not convert itself to another fiber, Type IIa will react similar to either IIb or I depending on the training.