Strength VS Size?

I recently received an e-mail from a client that asked:

Jason,

I hope this email finds you well and that your semester has come to a peaceful end. I do have one question, if I may trouble you for a moment.

Does strength training negate muscle building?

The premise of this question is that few reps with heavy weights tend to build strength and light weight with high reps build bigger muscles (pumps them full of blood and they tend to get larger but not necessarily stronger). If this is incorrect then the question is moot. But if someone does both types of weight lifting for similar muscle groups, does the strength training (heavy weights - low reps) negate the cosmetic features of muscle building?

James

A great Question. Are size and strength exclusive, can you train for one and the other at the same time, why are powerlifters so fat ? etc...

My answer:

Great Question James!

Do you mind if I use this Q&A as an article on my new blog?

Basically, for the purpose of education and simplicity, experts in the field of Kinesiology have categorized various intensity ranges as leading to one type of adaptation or another. This happens both in strength training and in cardiovascular training. Just think of the 'fat burning zone' for instance. Truthfully, the muscle really only knows two things; tension and total work. And the adaptations that occur to increase these capacities are not mutually exclusive.

Tension is a result of the percentage of muscle fibers recruited. Total work is a physical and chemical phenomena; physical by definition, ie Force times distance=Work, and chemical in the nature by which that work is accomplished via the bodies various energy systems. Force production by the muscle, and hence adaptations to strength training happen as a result of the interplay of these two factors. How big is the muscle, and how efficiently does it run? A V-8 that runs at 50% is no faster than a 4 cylinder that is running at 100%.

Tension , or the ability to apply greater tension, is the primary adaptation that leads to gains in absolute strength. This adaptation occurs most greatly when loads are at a very high percentage of 1RM. For instance, if one can bench press 100lbs once, and no more, then 100lbs is your 1RM. To lift 60% or 60lbs, would be a trifle. To lift 95%, or 95lbs would only happen on a good day. Because of the requirement to maximally fire almost all motor units when lifting a load that is 95% 1RM, the synaptic paths to these motor units are primed in various mechanical and chemical ways, allowing them to fire more completely, faster, closer to the same time, or in rapid succession better than they used to before. This may happen by way of greater potentiation, myelination of the nerves, or chemical adaptations such as metabolic balances favoring lower thresholds or 'potentials' at various points along the way. All of these adaptations can be summed up as greater 'neurological' efficiency. It is by these methods that the muscle becomes more effective in producing force without increasing in size. Pavel calls it 'upgrading the muscle software' in Power to the People, I often refer to it as turbocharging the engine you have rather than upgrading to a bigger engine.

Work, the physical/mechanical aspect, bears some explanation. Work is a measurement of energy, as are calories. Let's get physical for a minute:
Force (measured in newtons, is anything that tends to cause acceleration, or a change in velocity) applied over a distance (linear or angular (that's where Torque comes in) measurement) is considered WORK. Work divided by time in physical terms is power. Calories are related to Joules. Joules/Time=Watts. Newton*meters/second=work. Well, as most of us remember from some sort of science class, energy is neither created nor destroyed. As such, in order for muscles to put out work, they have to put energy into the system.
Where this energy comes from, how much of it is needed, and how long it must be delivered to the muscles and out of the system are the primary variables in exercise selection and adaptation to them. All exercise is exo-thermic. Energy is given away, or put into the system or out of the body. The more reps done of something, the more the total work adds up. As a function of the longer time it takes, power output is often equal or less. The greater rate of power output times the greater length in time will equal greater and greater energy expenditure. It will also mean that the bodies choices for energy systems will start to shift. Here's some info about the body's energy systems for weightlifting type work;

ATP/CP: Quick and powerful fuel stored in the muscle. Under maximal power output may last 1-3 seconds, submaximal efforts can use CP for up to 30-60 seconds. It is depletion of these stores that encourages muscles to become larger, in an effort to store more mechanically.
Glycolosis: really gets going after 30-40 seconds, so really gains ground as ATP/CP taper off. Uses glucose, or sugar, in the muscle and blood to fuel work. Becomes insubstantial after about 100-150 seconds. Creates acid as a byproduct, lowering blood pH and eventually causing weakness, fatigue, nausea and an inability to continue producing force and or working out! When this energy system is taxed maximally, the organism becomes a better chemist. The buffers that stabilize pH and the cardiovascular components that shuffle chemicals around increase in capacity, thus delaying what is often referred to as the Lactate Threshold.
Aerobic: A long series of chemical reactions essentially leads to the use of oxygen to break down fat into energy. This takes 90 seconds or more to really get started, but can operate at submaximal levels for hours in some better trained endurance athletes. Faster delivery of oxygen, and an increased capacity to take it up are the primary adaptations to this stimulus.
The key is that if you were to graph these three sources, they would each look like a parabola. The x axis being time, and the y axis being energy contribution. Each overlaps the other, kind of like the Golden arches times three, such that at about 45 seconds, on average, the energy supply would look like this:

45 seconds;
15% From ATP/CP
15% Oxidative
70% Glycolitic

There is really a mix of energy sources supplying the energy required to perform the work. At any time between 10-100 seconds, this is always true. Hence, there is no weight, load, intensity or duration in typical strength training protocols that really isolates one source of chemical energy. And, there is no way to isolate one type of metabolic adaptation either.

Very long story not so short, there will always be some crossover. For example, if I choose to do 10 sets of 3 at 90% 1RM ( a classic powerlfiting protocol to increase absolute strength), I will experience a great deal of neuromuscular adaptations. I will become very efficient at that exercise, and strength will increase rapidly. Since the sets last an average of 15-20 seconds or so, I will use 90%+ ATP/CP, and I will reduce the available pool ENOUGH such that I will elicit some adaptation in the ability to store more. IE, my muscles will eventually get somewhat bigger. Even though traditionally, a S&C text will tell you that it is a strength training range, and not for hypertrophy. There are a great number of variables that could augment these results. Due to the time necessary to fully replenish CP stores between sets, this workout would lead to entirely different adaptations if it was perform with 90 seconds rest between sets versus 300 seconds.

The body is an amazing adaptive organism, and will take the path of least resistance. Ie, if you reach a high level of relative strength, it will be easier to become stronger by simply getting bigger. So, even if you utilize low-hypertrophy methods, the organism may see increases in mechanical size as an easier way to gain capacity than via greater neurological efficiency. It is like the Pareto Principal, or 80/20 rule. If greater force production is needed, and neurological efficiency is already at 95% and size is at 5%, it will be much easier to gain that force potential through size increases (which will require 20 to get 80) than it will be to make an already highly efficient mechanism even more efficient (spending 80 to get 20).

If you know what energy systems your are taxing most, and how completely you are taxing them, you have an excellent guide as to what adaptations to expect. If you wish to increase relative strength by way of greater absolute strength with no mass gains, you would be wise to avoid a great deal of total work, high volume and short rest periods. These will all encourage the muscles to get bigger. Especially at 60-85% of 1RM. Don't worry about the swings and kettlebell snatches. They are a little too light. Think of them as somewhere in the middle, using a 20-40% share from all three sources, providing an excellent method to use all forms of energy without gaining too much mass. In fact, a steady diet of KB Snatches and Swings is a sure fire way to burn fat and gain the work capacity of the T-100.

Good Luck in your training!