Let’s be honest – the human body doesn’t love change. Given that we are all still recovering from Daylight Savings from a few weeks ago, we are all feeling evidence of that firsthand! Or think about when you suddenly up your macros and your body bloats and feels “off” for a week or two before normalizing again – change messes us up.
That’s why it’s so great to change things around.
You’re probably familiar with the term “plateau” in regards to training or dieting – when your results begin to taper off after a given period of time. Whether it’s an inability to continue losing or gaining weight, or a constant miss when trying to increase lifts or performance speed, it’s really frustrating. That’s usually when it’s time to make a change by switching around macros or integrating new training techniques like a super-set. But why does the body adapt? Why is change so effective? How does this relate to Crossfit?
Your body is always going to fight for homeostasis (staying exactly where it is). At the same time, however, your body is also going to try to do whatever it can to make things easier for itself – that means adapting to your current diet or training routine, to conserve more energy and tolerate working with less. This is called metabolic adaptation. I want to talk specifically about metabolic adaptation as it relates to training, and how your body adjusts itself to increase its efficiency and capacity.
Let’s get nerdy. First off, your body has 3 main energy systems, all using ATP (adenosine triphosphate) as it’s energy source. Here is how your body creates ATP, first with the “ATP-PCr system”:
- ATP is a molecule found in cells responsible for transporting energy, used by your metabolism, to where it is needed
- PCr (phosphocreatine) is a molecule found in cells responsible for storing energy
- When you begin working out, high oxygen use kicks off the need for more energy in the form of ATP
- Once at its destination, ATP breaks down into ADP (adenosine diphosphate) and this releases the energy needed for muscle contraction
- When your body’s ATP stores begin getting low, the PCr molecule releases a phosphate to help build the ADP back into ATP to recycle for future use
- This type of energy is most utilized in high-intensity settings, or short bursts of work, because these energy stores run out in about 10 to 20 seconds before needing replenishment
So say your body is doing more than 1o to 20 seconds of work? Now, your muscles’ need for oxygen has gone beyond their oxygen supply. This is when the “glycolytic system” kicks in to make ATP:
- The glycolytic system uses glucose as it’s energy source
- Glucose is stored in the muscles and liver in the form of glycogen and is used when your body is in anaerobic (“without oxygen”) activity
- Once utilized, your body produces something called lactate, which lowers the pH of your muscles and blood (we’ve all experienced lactic acid build-up before, which makes us feel sore!)
- Lactate, during exercise, builds up faster than the body can remove it
- This energy system keeps us going around 30 seconds to 2 minutes, where then the pH of your muscles no longer supports ATP production
This is where your last energy system kicks in, when you need to begin maintaining longer bouts of exercise, such as an endurance run, with the “oxidative system”:
- This system uses oxygen to create ATP within your muscle cell mitochondria (found within the cell)
- ATP cannot be created very quickly or efficiently here because it involves more chemical reactions to take place, which is why it’s best used for endurance type training
- Carbohydrate and fat stores can also be utilized for creating ATP with the oxidative system (your typical “fat burning” workout)
Still with me? Ok – hear me out. The body is an efficiency machine, designed to adapt to these kinds of metabolic stresses or find ways to make things more comfortable for itself.
First off, your body can simply get better at storing PCr in your muscles for more readily available use! The more you have stored, the higher the intensity you can work before you need your glycolytic system to kick in.
Your body can also increase its tolerance of lower pH levels when lactic acid increases in your muscles. This means you can keep going, for longer, before feeling fatigued.
Additionally, the process involved with removing lactate from the muscles during exercise can speed up, thus buying you more time before your oxidative system needs to take over.
Last, training increases capillaries in your skeletal muscles (not to mention hypertrophy), which lets in increased blood flow, as well as increasing your mitochondrial count, to allow for more oxygen production in the oxidative system.
This is what makes an efficient athlete!
How Crossfit busts through adaptation
After a period of time, your body will adapt to whatever you are doing – no matter what. Say you’ve been going steady on a given routine for a few weeks – well, your ability to store PCr goes up, your muscle fibers increase and create more oxygen, and you can push harder, longer. But you don’t adjust your routine … you are going to stop seeing changes, because at this point your body requires harder work to move forward.
Crossfit is anything BUT a routine! Think about it – you hardly touch the same movements in the same week (unless you’re unlucky and you end up with 2 WODs containing burpees in a matter of days). You almost never do the same things back-to-back. You are constantly keeping your body guessing, and so you don’t even get the chance to hit a plateau. Crossfitters, even when they Rx all the weights in a WOD (or Rx+ if you’re intense), can still strive to be faster and more efficient in their workouts, so there’s rarely opportunity for plateau-driven triggers.
I witnessed the beauty of this a few days ago, when training alone while out of town. My rest days happened to always line up with deadlift technique days at my box, so I wanted to work on my deadlift max on my own time. I wasn’t feeling too confident about it, given that about a month had passed since the last time I pulled! I loaded up the bar, working up to my old max, and it went up easy. I added a little more … and it just kept going!
While I’m still in that “newb gains” realm within the Crossfit world, the more I thought about it, the more I understood what was happening.
Crossfit throws every available movement at you in a matter of weeks. You may not do something, like deadlifts, very often, but in between those deadlift days, you are working the muscles necessary for an amazing pull the next time. You get stronger and stronger in the days leading up to your next shot so that, come the time, you can make a great effort and surprise yourself with your progress.
Crossfit athletes sometimes get a bad rep for not being “that great” at certain lifts. We get it – it isn’t all we do. But that’s not the point. Crossfit is about being a well-rounded athlete; we don’t specialize, we try it all instead. Each movement we do, in turn benefits the others so that we are constantly building ourselves better for the next day. We do this by keeping things different day in and day out. We maximize our ability to adapt.
The next time your doing your workout of the day, think about how your body may have metabolically adapted behind the scenes. Maybe you’ll notice it in the way you can regulate your breathing longer before getting winded, or how the burn in your legs takes a few moments more to slow you down. Maybe you won’t even notice because you’ve adapted too – and made yourself work harder to match.
“Chapter 3.” Physical Activity and Health: A Report of the Surgeon General. Atlanta, GA: U.S. Dept. of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, 1996. 61-77. Print.
“Adenosine Triphosphate.” Wikipedia. Wikimedia Foundation, 13 Mar. 2017. Web. 16 Mar. 2017.
“Metabolic Adaptations to Exercise.” PT Direct. N.p., n.d. Web. 16 Mar. 2017.