It’s true that you can cause type IIa to become IIb, and vice versa, but lifting in the 8-12 rep range as you advocate turns IIb into IIa, not the other way around. That’s because any set lasting over 30 seconds needs oxygen to continue. Oxygen is used by mitochondria, which give a muscle fiber it’s color (or lack thereof). Type IIb is the power lifter’s fiber; Type IIa is the body builder’s.

Also, it takes up to 48 hours to replenish intramuscular glycogen stores through feeding. That’s why marathoner’s don’t do any running the 4 days prior to a marathon, to not only replenish their stores, but to allow ample time for supercompensation. For the average hardcore long distance runner, they run 5 or 6 days a week. That leaves no real time to ever fully refill their glycogen. In addition, the whole point of the long distance run is to exhaust the body of it’s glycogen stores completely, in order to train it to conserve better the next time around. Those runs, repeated over the course of months, or years, is what leads to upper body muscle loss. This is why colds are so common amongst runners, as all the neoglucogenisis depletes the body of glutamine stores, and glutamine is one of the primary fuel sources for your immune system.

Leaving that aside, you still haven’t explained why the law of specificity of training prevents someone from getting absolutely ripped upper bodywise, while only suffering stagnation in their legs. You also haven’t explained why speed skaters, or hockey players, or Tour de France cyclists have quads that look like they would be at home on a thoroughbred.

Overtraining is one point where you are right, it could be easy to overtrain your legs if you do a lot of aerobics ontop of a leg lifting workout. Like I said though, it’s all about being very precise in how you train and how you eat.

Mike this is for you, I am doing all my work out with only 10 seconds of tension and concentric and eccentric as fast as I can. I am having the best gains of my life. I started to try this at first because with more than 10 seconds, when with maximal velocity, the type IIb (the ones that get most hypertrofied) are fadigated. Since F = m. a. I am recruiting the maximal fibers that I can. About the eccentric Ive been reading some studies that show that when the eccentric is like 1 second or less it gives more hypertrophy, its hypotetizated that eccentric fase works forward concentric when talking about fiber activation.
The bad is that this kind of training may be easier to get a lesion.
Well, just my thoughts about. If you wanna try, its working a lot for me.
btw: better results than with THT.

Cya.
if you wanna talk feel free to mail me, I can send some studies to show scientific proof of what Im saying.

I train THT style for 3 weeks know, no cardio at all EXCEPT the half-hour bike ride to work and back every day. Does it hinder me in any way? I prefer the bike to public transport 🙂

The fiber itself does not get smaller as a result of its mitochondrial density. The reason people who engage in a lot of cardio typically have smaller muscle size is that they often exhaust their intramuscular glucose supplies, and force their muscles to engage in neoglucogenesis (a fancy term for how the body converts protein to glucose). Doing this habitually, combined with heavy lifting, means the body will be breaking a lot of protein down to power a workout. To counter act this, the body would need even higher levels of protein intake, as well as sufficient carb intake to keep.

After all, if it was about muscle fiber type only, the law of specificity would suggest that you could still get huge on top, but just have skinny legs (hamstrings in particular). Most long distance runners (esp the pros) have pretty big hamstrings and gluts, in fact. And the Tour de France guys have giant quads, despite spending hours upon hours on the bike. It’s just that these guys are small on top.The reason is that their body keeps stealing the protein for the neoglucogenesis from muscle that is the least active, which for runners and cyclists is their upper body.

Your body can only replenish glucose stores at a certain rate, however, so I think there is a limit to how much you can mix heavy lifting with heavy aerobics, but I do think its possible. Personally, I added close to 10 lbs of muscle and added strength in every body part that I train while training for a marathon last year. I was hawkish in terms of the amount of protein (esp glutamine) that I consumed, as well as consuming extra mid cycle carbs to help keep glucose demands met. So it’s doable, though more difficult to get right.

Other than that, zip, nada, nothing – and I can keep up with the guys who play 3 times weekly (ball hockey), more than once weekly at ice hockey AND some also do other cardio.

Great article Mark!