Why do we love CrossFit? Some of us will say its constantly varied, high intensity workouts, while others will say lifting weights. Both are super important and play a huge role in our overall fitness, which is why CrossFit's methodology truly works. Most of you know to improve your fitness, you need those high intensity metcons in your life. The ones that we all have that love/hate relationship with. However, it is important to understand the other side of it: why we need to lift heavy often!
One question you might have is, why do we program moderate to heavy lifts multiple times per week? There are tons of benefits of lifting heavy such as building strength and increasing performance, burning body fat, building lean muscle etc. Every day before class you will typically hear your coach talk about what the intended stimulus is for each metcon, whether it be a short sprint or a steady sustained pace over a longer time domain. However, when we perform our strength portions of the class, it is important to understand why we use such heavy percentages. (3x5 @ 70-75%, 4x4 @75-80%, 5x3 @ 80-85%, build to a heavy single for the day, or test your 1RM). From a high level, when heavier weight is lifted, it requires a lot more of your muscle fibers to activate in the body, which then releases hormones in the body which in turn leads to strength gains. By doing this, you are essentially developing your neurological system or Central Nervous System (CNS).
What is your Central Nervous System? Your CNS is made up of your brain and spinal cord. Its main job is to gather information from the body and send out instructions to perform an action. Most of the nerves in your body connect to the spinal cord, which sends messages to your brain. Your brain then receives the message and controls your response. For example, if you want to move your right arm, your brain sends the message back down your spinal cord to the nerves and your arm moves. Everything you think, do, and feel is derived from your CNS. Have you ever picked up an empty barbell and said to yourself "Shit, this feels insanely heavy today." OR, "WOW this feels so money today, def gon crush!" This is your CNS speaking to you. If you aren't testing your true limits when lifting weight, you will never develop your CNS. When you lift at the prescribed percentages, and/or build off previous weights lifted, you should feel extremely taxed mentally and physically, with the occasional "seeing spots" (those of you who have experienced this will know exactly what I mean.) The purpose of this stimulus is to tax the CNS which in turn stimulates strength and muscle growth. If you aren't lifting at your true percentages, your body will never experience this "fight or flight" mode and thus, if it doesn't challenge you, it won't change you. As a result of using your true percentages, your strength will increase, and make much of the lighter weights used in metcons feel even lighter.
Here's a tip to spark your CNS that has worked for me. Next time we back squat, as a part of your warmup, try to build to a heavier percentage than your actual working weight. Then drop back down and start your working sets. For example, let's say it's 3x5 @ 70-75% of your 1RM. Many of us use the first few sets to warmup and build to our 70-75% and then start your first set. Next time, try to go PAST that and build to about 85% and perform one rep. Then drop back down to your working weight and start your first set. This will ultimately make your 70-75% feel a lot lighter because your CNS has sparked by feeling a much heavier load.
All in all, if you want to increase your strength and performance in the gym, you need to develop your Central Nervous System and one of the best ways to do that is to lift heavy often.
See you at the barbell.