higher weight/lower reps or vice versa?

I am not quite sure I understand the science of weightlifting yet. With higher weight and lower reps, you build more muscle than lower weights and higher reps? I keep reading and learning, but there's so much info, much of it conflicting.

Thanks for being so patient with this weightlifting virgin....

Don't worry, there isn't much science yet.

No.

Anytime.

The general consensus is that doing more than 15 reps is a waste of time. Some people believe that a higher number (up to 20) is appropriate for leg work.

As for weights used, people use anywhere between 60%-100% of their 1 rep max, depending on intent. When powerlifters do use weights in the lighter range (around 60%), they do the reps explosively, generating maximum force with each repetition. So even though the weight used is low, the force generated is extremely high (you generate more force in a 60%1rm explosive lift than in a 1rm).

For bodybuilding purposes, I'd recommend using weights in between 75-85% of 1 rep max, and possibly doing explosive work with lighter weights. The number of repetitions depends on training style (in particular, how close to failure you wish to push a given set, and how many sets you wish to do).

Why is doing more than 15 reps per set a waste of time? I'd assume it would depend on one's goals.

Of course (that's always true). If your goal is strength and/or size, it's a waste of time (except, as Donovan notes, for legs). If your goal is muscular endurance, 12 or more (possibly many more, depending on the situation) is the way to go.

What Wayne said. Also, I think Donovan was assuming that the goal was strength and/or hypertrophy and discounted the possibility of training for endurance.

Subject: Re: HST Routine Questions

Ok, you asked. When a muscle has to generate force, it has two primary strategies to do so: recruitment and rate coding.

One is through increased fiber recruitment according to the Size principle (which says that size doesn't matter ; no, wait, that's Cosmo). The Size principle simply says that muscle fibers will be recruited from smallest to largest based on need (it actually has to do with the electrical resistance of the motor nerves but that's way more detail than anybody needs). So fibers recruit from Type I (smallest, lowest force generation) to Type IIa (larger, medium force generation) to Type IIb (largest, highest force generation).

The second is via rate coding which simply refers to the number of electrical signals (in hertz, signals per second) which are sent to the muscle. More signals causes the muscle to contract harder (for a bunch of complex reasons that would require graphics to explain).

Now, in certain small muscles (oddly called constrained muscles, stuff like the eye and crap like that ; nothing bodybuffers care about) the body will use recruitment up to about 50% of max force production (how do you measure 1RM for an eye muscle anyhow) and then use increased rate coding from then on up. The reason has to do with control, you find that in muscles that have to be under very fine motor control (such as the eye and fingers), rate coding gives the body a better ability to modulate force production in very small amounts. We don't give a shit about those muscles unless you want big freaky eyeballs anyhow.

Ok, in every muscle we're concerned with as athletes, the body will use recruitment up to about 80-85% of max contraction force (again, close enough to 1RM for us to use that). There may be some variance between different muscles as well but there's not enough data (that I'm aware of) to be sure. Beyond that 80-85% mark, the body will used increased rate coding to generate more force.

Meaning this, at the 80-85% 1RM mark, you have recruited every muscle fiber that you are going to recruit from the first rep. You are getting 100% recruitment. Below that, you won't get 100% recruitment (although you may reach it as some fibers fatigue and quit generating force). But above that you don't get any further fiber recruitment. Now, depending on muscle 80-85% is about 5-8 RM or so (seems to depend somewhat on the muscle with legs being towards the higher end of that range). Keep that in mind.

So look at what we're trying to achieve for hypertrophy. yes, recruitment is a key aspect ; yes, tension is a key aspect ; but there are also metabolic factors involved in the growth stimulus (this is all on top of the mRNA/ribosome/mechanogrowth factor/satellite cell issues). To get an optimal growth stimulus, we want to maximize all of those at once.

So say you're working at 60% 1RM (about 20 reps). You don't get max recruitment, you don't get as high of a tension, but you get a lot of metabolic effects.

Now look at 100% 1RM (1 rep), you get max recruitment (but no more than you would have gotten at 80-85% 1RM), you get max tension (higher than you'd have gotten at 80-85% 1RM) but you don't get nearly as much metabolic changes.

Now, at 80-85% 1RM (again, 5-8 reps or so), you get max recruitment, you get an intermediate tension (higher than at 60% but lower than at 100%) and you get intermediate metabolic changes (higher than the 1RM but lower than the 20RM).

So as per the other post, it's a matter of competing process and trying to maximize each of them as much as possible. A 1RM maximizes tension and recruitment but severely limits metabolic factors. A 20RM maximizes metabolic factors but severely limits tension and recruitment. A 5-8RM gives you the highest overall levels of each: recruitment, tension AND metabolic factors.

And now you know....the rest of the story.

Lyle Pedantic note: researchers actually use Maximal Voluntary Isometric Contraction (MVIC or sometimes just MVC) to measure the above percentages and neurological factors. So technically you get max recruitment at about 80-85% MVIC. For our purposes, 1RM is a reasonable proxy for MVIC. It's not as clean, but it's close enough.

and i would disagree with the general consensus. i think most sets should be less than 15, but that occasional work of higher than that would be beneficial.

imo

i think that is with the understanding that this is for improving limit strength, or hypetrophy. if your goal is strength-endurance or other such stuff, obviously higher reps would be nice

Sounds good to me.