Well, as some of you know, I'm a low rep type of person, and rarely do I venture into anything above 5 (I like singles, doubles, and triples the best though, for high sets, like waterbury's 10x3, or just a bunch of singles, etc.). I've come to realize though, that, it's a real pain to do higher reps now that I've been focusing more on lower reps. 3x10 is harder to me than 10x3 now. Would this perhaps be an effect of the Type IIA (I think that's them, the "intermediate" fibers I guess you can say) shifting and taking the characteristics of Type IIB fibers? I just find it funny that I have a helluva time doing bench with 125 lbs. for 10 reps, but find it easier comparably to do 160 for a few sets of doubles. I'm turning into some sort of low-rep freak!
It probably feels easier because you aren't used to exercising for that length of time ie. doubles are a brief workout, but the last few reps of a set of 10 can be pretty laborious. Those poundages correlate fairly well actually if you go and look at a rep calculator like the one at bb.com. I would definitely recommend at the age of 17 that you venture into some higher rep work. In fact, I would recommend that anyone who always does low rep work should in fact do some higher reps. Many people believe that the older you get, the lower your best rep range will be ie. if you are fairly young, then the best rep range to produce hypertrophy/strength will probably be higher than the normal low reps eg. around 8 reps.
So you're saying it's, in a nutshell, conditioning? I've conditioned my body more towards lower reps. Meh...I guess I gotta get cracking on some higher reps then... I'm not going higher than 10 though...(yes, my rebellious teenage attitude is starting to come out...go ahead, send me to my room without dinner.... )
Like you, most of my adult life has been spent in low rep work for weights. but the best results I have ever gained have been from varying the poundage to increase or decrease the reps. A method that has worked well for me is changing from high reps (6-7 ) to low (2-3) and repeating for the desired amount of sets.
