So lately at the box, I seem to be having this conversation a lot. We’re working on a strength set, perhaps it’s deadlift 3-3-3-3-3, and I have people finished the entire workout in under 10 minutes. So we have to sit down and have a little talk about basic human bioenergetics, and how it applies specifically to the type of lifting that we do.
Alright, let’s back it up for one second and briefly cover the three MAIN metabolic pathways in which ATP (the body’s energy currency, if you will) is produced. Think of ATP as the energy that actually makes things happen in your body. To make a long story (very) short, ATP, or Adenosine TriPhosphate, is broken down into ADP, or Adenosine DiPhospate. When this breakdown happens, energy is released, and that’s what chemical reaction basically powers ALL human movement. Now, we have three main ways of producing ATP.
1. Phosphagen – high intensity
This is the main energy source for extremely short, high bursts of power and intensity. I won’t get into the specifics, but basically your body is adding a phosphate group (PhosphoCreatine) to ADP, and then Creatine Kinase chops it back off again. This is the fastest way your body can create ATP, but will only last for exercise less than five seconds. So when you perform a power clean or a 1RM back squat, you’re mainly using your phosphagen system to produce energy. Oxygen is not required for this reaction.
2. Glycolysis – moderate to high intensity
The second fastest way that your body produces ATP. This is basically the breaking down of glycogen (stored carbohydrate/glucose) in the muscle. Again, making a long story short, your body uses this complex process to create ATP that we can use for exercise lasting up to approximately 3 minutes. This is why, as CrossFitters, we should try and consume a moderate (that’s moderate, not HIGH) amount of carbohydrate in our diets. We need to make sure that both our liver glycogen and our muscle glycogen is full before attempting any metcons. If you don’t believe me, try eating low carb for a week and then do Fran. Then come back and talk to me about how you felt during your performance.
3. Oxidative – low intensity
This is where your body begins to use oxygen to fuel the muscles with the carbohydrate and fat that is in your body. Using two systems, the Krebs Cycle and the Electron Transport Chain. Not to get into too much detail here, but if you go out and run a 5km race, you’ll mostly be tapping into this system. It produces ATP at a much slower rate than the other systems, but will last for several hours or more.
At least a basic understanding of these systems is necessary to begin to understand why we rest between sets. Let’s go back to our initial example of a 3-3-3-3-3 deadlift. We do our warmup sets and start to feel pretty good, and we hit the first set at 315lbs. Say our max is around 400lbs, so this is just over 75% of that. The first set feels relatively good, as we are tapping into a fresh and full phosphagen system to create the energy for the lift. Because it’s relatively light compared to our max, we don’t fully deplete our stores. But we DO want them full again before we lift, so we need to wait. We rest 4-5 minutes and lift again, this time at 335lbs. Starting to get harder now. It gets evermore increasingly important to rest the closer to our max we get.
WE NEED TO LET OUR BODIES REPLENISH AS MUCH PHOSPHAGEN AS IT POSSIBLY CAN BEFORE WE MAKE OUR NEXT LIFT.
Generally, it takes between three and five minutes to do this. This is why your 1RM is not the same as your 10RM. Because you’ve completely depleted your phosphagen stores after a lift or two, and are now running on glycolysis to finish the set, and as we learned before, Glycolysis can’t produce energy as fast.
Now, keep in mind that as you progress through your 3-3-3-3-3, your phosphagen stores will slowly decline and you won’t be able to get as much power back each time. That’s why you’ll never see a coach let you try and hit a new 1RM nine times if you keep failing. If you’re failing, then there’s a reason for it.
The bottom line here, even if you don’t care to understand any of the science here, is that you can’t rush strength. If you want to see the gains, you need to lift properly, and that means resting between your sets.
NOTE – this does not specifically apply to beginner lifters. At the start (and I mean START) of any strength program, your body needs to go through a phase of learning how to do the movement properly before you can properly make actual STRENGTH gains, and WAY before you should actually max out. Your body needs to make neuro-muscular adaptations, learn proper motor-recruitment, etc… before the strength gains start happening. If you’re just starting out, I would urge you NOT to attempt any kind of max effort lifts for at least a couple of months. Talk to your coaches and see when they feel you’re ready, as it’s going to be different for everyone.
Think of neuro-muscular adaptation like this: When you start with a lift, say the deadlift, you may not be able to lift more than 135lbs the first time. Within a couple of weeks, you may be up to 270lbs. Now, that’s a DOUBLING of your max, and only in two short weeks. This doesn’t mean that you’re twice as STRONG, it means that your body (nervous system, muscles, brain, etc…) has learned HOW to do the movement properly. At this point, your gains will begin to get smaller. Don’t be discouraged though! Look at it as a good thing. From here on out, all the gains you make will actually be you getting stronger, and isn’t that the whole point of this anyway?
So train smart. Take your time. Be vigilant about your rest between sets. Because don’t we ALL want to continue getting stronger?