Warm Up Tip for Immediate Increases in Strength – Post-Activation Potentiation

Here’s an interesting little warm up tip that will make you a bit stronger on your heavy, low-rep working sets. It is based on the neurological phenomenon of post-activation potentiation. This is actually why things like ‘wave loading’ work for example. 

Post-activation potentiation can cause an immediate increase in maximal strength due to the effect it has on activating more motor neurons, and subsequently muscle fibers for your working sets. When a motor neuron is activated, all of the muscle fibers innervated by the motor neuron are stimulated and contract. When more motor neurons are activated, more muscle fibers are activated. The more muscle fibers activated, the stronger the muscle contraction. So essentially, the higher the rate of motor neuron recruitment, the stronger the muscle’s potential to contract against force and the stronger you’re going to be.

The Size Principle says that motor neurons are recruited in an orderly fashion – from smallest to largest, which also means fewer fibers are recruited at first and then progressively more fibers are recruited to perform based on the increasing motor neuron activation. Increased loads and trying to do the concentric portion of your reps fast/explosive (doesn’t mean it will be fast, but the effort is for it to be; if the weight is heavy enough it won’t be ‘fast’) increase activation for example.

So the brief science aside, how can this be used? Again, I have used it only for my heavy work, say for example if I was doing heavy squats, or benches and my working set reps were going to be in the 4-6 range. This obviously does not lend itself well to dumbbell work.

An example will illustrate it best. Let’s say my planned working sets for the full squat was going to be 275 lbs. My warm ups would look something like this:

Warm Up – 95×5

Warm Up – 135×5

Warm Up – 185×3

Warm Up – 225×1

Warm up – 255×1

Now here is where what I’m talking about comes in. Typically at this point, we’d get to our work sets. But to take advantage of post-activation potentiaton, I’ll do one more warm up set.

Warm Up – 300 to 315×1

So it is essentially a supra-maximal warm up set. What did that rep do? Because it’s heavier it has caused a greater activation of motor neurons and subsequently muscle fibers. if I stopped at 255, I’d have less neural activation than I would with doing the supra-maximal warm up rep. So my nervous system is charged up more than it would be otherwise. This can also be done with a supra-maximal hold at lockout instead of a full rep too – you could use even more weight for that.

When I drop back down to 275 for my first working set, I can guarantee my performance is going to be better having done the 315 prior than it would be had I stopped at 255 on my warm ups. And it always is. I’m going into my working sets with more motor neurons and therefore more muscle fibers activated. End result? Immediate increase in strength. (Also, the time between my last warm up set (the heavy one) and my firs working set is not all that long – probably within 60-90s and I’m getting started.)

If you have such loading parameters (set/rep protocols) in your program, maybe give this a try. If you’re unsure of how strong you are, be sure to have a spotter until you get an idea of the right load for you.

Remember, this isn’t a max effort rep that you grind out and barely make. It is a heavy rep, but you can do it smoothly with no help.