What does this mean? Have something to do with muscle fiber make up? Is it normal to have an ideal rep range that you perform well in? and can push yourself very hard in?
thanks in advance.[/quote]
It’s a combination of 3 factors :
1)your fiber ratio, you seem to have a combination of Type IIa/IIb or IIb-dominant, which is actually pretty good for weightlifting/hypertrophy.
2)Fitness level/GPP/‘training age’. High rep ranges are harder for the cardiovascular system, your lactat acid tolerance might be pretty low since your body is not used to that kind of rep range.
Also, the longer you are training in the “classic” hypertrophy ranges, the more efficient you become at recruiting more fibers at once, which lead a)to a much higher 1-5Rep max but also b)to the fact that, if you don’t train for it specifically, your relative 15Rep weight goes down.
(i.e. when you train for 6 month you could bench 200lbs for 1rep and 160 for 12 (80%), after 4 years you might be able to do 400 for 1 rep and 280 for 12, which would only be 70% since your 1RMax is twice as high)
3)The order in which you are doing the sessions. For example, if you do a low rep day, than a high rep day, then a rest day and repeat, you won’t feel as good on your high rep day since you haven’t fully recovered yet (or at least you are not as recovered as on your ‘heavy’ day)