This week for Wednesday Write Up we are going to get a bit sciency and discuss something that I think is important to understand when it comes to body composition and using CrossFit as your method of fitness. There are endless ways to exercise and every single type will say they have unique reasons for why they are the best and why you should use them. In my opinion, in being involved in the fitness industry for more than ten years now, I feel CrossFit and specifically how we practice CrossFit here are Outlier offers the most potent dose of fitness and what your body gets out of it is the most bang for your buck! In order to better understand why CrossFit is so potent, we are going to go through the history of when aerobic classes were king and the weights were kicked aside when it came to weight/fat loss
Lots of fitness practices bost and talk about calories burned during the training time. You can buy all sorts of devices nowadays that track heart rate and or calories burned by your body. For a long time cardio or aerobic exercise was thought to be king for people that wanted to maintain or lose bodyfat/weight for health. This was the obvious choice for lots of people because you can burn lots of calories if you stay moving for 50-60 minutes straight. This is where spin classes, standard running, or hour long step aerobics come into the spotlight. For a long time people thought that weight training was only for people that wanted to gain weight/get bigger. Luckily over the last decade there has been lots of studies and evidence to show that weight training is just as if not more important for building and maintaining a lean body.
There are a few reasons why weight training is just as if not more important than cardio training alone. My favorite analogy is imagining that your body is a car. When you do cardio, you burn calories or burn off fuel that your body has. Whether it be blood sugar or if you have been doing a long enough cardio session your body will steadily start to use body fat as a source of energy. This is commonly known as the famous “fat burning zone” this heart rate range is typically considered the orange zone on the treadmill and what the brand Orangetheory Fitness banks on. Cardio burns off the currently available energy while the benefit of weight training is a bit different. Weight training also burns calories while being performed.
For the sake of discussion I will frame weight training in this regard as standard body building 3×10-15 of typical isolation exercises with some larger compound movements like bench, squats and deadlifts performed with rest between sets where the heart rate is not elevated drastically. While the calorie exchange for this activity doesn’t create as much of a demand as cardio, the main benefit shows up once the activity is over. Steady state traditional cardio doesn’t take long to recover from. After about 20-30 minutes your body is pretty much back to baseline. Once you have something to eat, the blood sugar is regulated fairly quickly and all is back to normal. With weight training your body has to work much harder for a longer period to recover from. Replenishing the energy stores that are within your muscles take longer for your body to do. As well once your body has recovered, over time your muscles become denser or larger. This means that know your body/car has a larger engine. Weight training builds a body that burns more calories at rest and even more calories when the body is put through activity.
An example for why weight training is important for maintaining a lean body is that when you develop a regular weight training habit your body learns that the energy stores within the muscle fibers. Versus when long cardio sessions are the dominant exercise plan, your body will actually be more apt to store excess calories as body fat. This is because blood sugar and adipose tissue (visible body fat) and intramuscular (like the marbling of a steak) fat is the main source of energy for long cardio and blood sugar, ATP, muscle and liver glycogen are the sources of energy for weight training. Your body may choose to store extra energy in certain ways because that is what you are teaching it do each day with your exercise regimen.
Now that we have talked about some of the main differences and benefits of weight training versus cardio training. Let’s talk about the vast importance that we now know of intensity in your training plays and how this impacts your exercise.
Another revelation that has been seen over the past decade is that when it comes to exercise, quality beats quantity. Being active or exercising for a long bout is not as beneficial as completing a more intense workout that doesn’t take as long. Whether you apply this principle to cardio training or to weight training, higher intensity yields more results. The mechanism for why this is better for weight or body composition management is similar to why weight training is equal to or more important as cardio. Completing long slow cardio isn’t that hard for your body to recover from. Shortly after you finish your session the body gets back to baseline very fast. Higher intensity workouts elicit a greater EPOC (excess post-exercise oxygen consumption) response.
To reach back to the car analogy, if you drive around surface streets at a slow crawl and stop. It won’t take long for the engine to cool down. Now if you go out and race down the freeway, race home (maybe going faster than the posted speed limit) and then turn the car off. You will be able to hear the engine cooling down and the metal clicking and settling. Just like when the car’s engine is pushed hotter and heavier your body will take extra time to recover because the level of intensity was much higher. That increased EPOC response can stretch over the full course of 24 hours at times. I’m sure all of you have done workouts where you could feel the aftermath the rest of the day. That means your body is burning bonus calories ALL DAY rather than just the ones you burn’t in the effort. As well, it is shown that when higher intensity efforts are put out, the fitness gains will typically be higher. The higher the fitness becomes the greater the effort will become and the greater the EPOC response will be. You can see how this can easily become a cycle for burning energy within the body for someone that trains with purpose on a regular basis. There have been studies that found even with traditional isolation exercises performed with restricted rest, the benefits are extremely beneficial. Imagine what that must mean for large full body movements like the ones we use in CrossFit!
Let’s start diving into the magic of the CrossFit program now that we have discussed the benefit of weight training and the importance of intensity. In a CrossFit class we work the entire body, granted days will vary and some days will have more focus on upper or lower body. Over all though, we hit most areas most days.
For the sake of an example let’s take the classic CrossFit workout Fran. 21, 15 and 9 reps of 95/65lb thrusters and pull ups (most likely kipping). The thruster is a large movement that requires a full front squat to be performed and then the transition into a push press. The first half of the movement involves all of the musculature in the legs as well as your erectors along your spine. The top motion requires all of the upper body pressing muscles. The pull ups (especially kipping) use all of the upper body pulling muscles as well as significant energy from the midsection and legs to generate the kip. Both movements at RX weight are going to be using the anaerobic (the energy pathway that is responsible for movements taking about 15ish to 2 minutes) and phosphagen system (0-15 seconds). Both of these systems do not use oxygen like the aerobic pathway does. The energy that is used is stored in the bodies liver and muscle tissue. These systems are meant for high power output but short duration. The recovery phase for using the systems are very heavy in using oxygen though.
When you go through the first 21 thrusters you are getting somewhat close to maxing out the anaerobic pathway and this isn’t for a small movement like bicep curls or tricep extensions so the hit on the body to try and recover all the involved muscles can be extremely intense (I’m sure everyone remembers their first time going unbroken and the sudden feeling of imminent doom). As with CrossFit protocol you go from the thrusters as fast as possible into the pull ups. Lets imagine you are fighting for the unbroken set and get it! Now you have just maxed out the phosphagen system for another huge muscle group. All while your body was trying to recover from the prior system being taxed. This causes your body to go into a major recovery mode for just about every muscle inside of you. The next round you go into 15 reps of each movement… but again with the protocol you don’t stand around and rest, you keep moving. This round now is a bit different, while the first round you may not have had to push to redline fully for the movements because you were fresh. Now you are getting closer to redline because you are nowhere remotely close to recovered. The phosphagen pathway may even max out and you need to stop to let muscles stop and recover, now you are having to tap into the glycolytic system to fight for the last reps in the set. Meaning the recovery stress placed on the body is that much more intense. Once you finish 15 you fight through nine reps of each movement to the finish line in a similar fashion. Putting the recovery ability and max output of these systems to work.
This same scenario can explain most CrossFit workouts. It is a balance of constantly pushing the output of the anaerobic and glycolytic systems of the major muscle groups of the body. In doing so we place the body under intense cardio-respiratory duress because the body is constantly trying to recover. In doing so, we create an experience where the effort that we typically put out for is between 10-20 minutes of metabolic conditioning (new age word for fancy cardio) as well as heavy strength training (which often is kept to time restraints through limited rest or within an EMOM set-up) which is all precursed by a solid 10-15 minutes of movement and dynamic warm up which gets the heart rate up a bit. This structure of practicing fitness allows you to grab all the benefits of weight training, cardio, as well as this all executed at fairly high intensity. As we discussed earlier, this will lead to a bigger stronger body that also is left running hot and burning extra energy off the rest of the day. A well structured CrossFit class takes lots of things we have learned about exercise to improve the body and improve the response of exercise and benefit the body over the past decade or so and multiplies it. We use large movements, we work at high intensities, we wave and structure the percentages we work at and we use big ranges of motion. The last thing that we do that really is the kicker of progress is variety.
We constantly change the programming and the structure of workouts. We only have a few workouts that we repeat as sources of data to see progress. This is why elite runners can run insanely fast but then die when you have them try Karen, which most CrossFitters would call a cardio workout. We don’t specialize in one movement or format. The body doesn’t get a chance to adapt and lose the benefit of the movements. The orders change, the weights change, the amounts of reps change. Nothing stays the same. As you get stronger and faster the workouts you repeat actually get harder because you continue to find a higher and higher redline to push to. There are new skills and movements to learn and implement into workouts. Going back to our Fran example, the first time you go from doing Fran with a gymnastic kip is a totally different experience than Fran with a butterfly kip. The butterfly kip can easily cut 30-40 seconds off your time when compared to the gymnastic kip… but that means the intensity is that much higher… and oh boy… do you feel it!
To wrap up this week’s write up I want to leave you with some closing thoughts. Remember that the calories burned during any given workout isn’t king. There are lots of other factors that go into whether a work out may benefit you the most for your goals. Lots of mainstream fitness organizations focus on one aspect of fitness measurement. Whether it be average heart rate, calories burned, distance covered… lots of these are good data points for what you did. Here at CrossFit we would say that we want the most data points possible to measure what we accomplished. So we lift weights, we run, we row, we cycle, we do pull ups we climb ropes… we do it in all different ways for different times. This way we make sure to get the most bang for your fitness buck.
Coach P
Here are two old school CrossFit videos that talk about a lot of the ideas I expressed above. I remember watching these videos after being in the fitness industry for several years and having my mind blown away and wondering why I hadn’t heard these ideas in other places!