Constantly varied, high intensity, functional movement is the core philosophy of CrossFit. All this means is that you should change up what you do in the gym and go hard on exercises that will likely carry over to day-to-day life. Personally, I think the most important piece of CrossFit’s training philosophy is constant variance. The qualities that make a movement “functional” are debatable and intensity is relative to each person, and the stimulus desired.
Varying movement selection on the other hand is a real thing, and must not be overlooked. The Law of Accommodation states that the response of a biological object to a given constant stimulus decreases over time; which is a fancy way of saying that after doing a certain exercise for a period of time, the body gets accustomed to it and stops adapting.
Some of the most common tests of athleticism are the vertical jump, and broad jump. In CrossFit, we do box jumps, which is a strong indicator of explosiveness. In my opinion, one of the most empowering things that we do in the gym is finding a max height box jump. Every time I see someone jump and land onto a box higher than they have before, they light up with amazement.
There are a few variations of box jumps that you can employ to jump up to your next personal best. The first is Depth Jumps - this variation utilizes the Stretch Shortening Cycle. You will drop off of a box, and immediately rebound onto another box that’s higher than the one you dropped from. When you land, your muscles experience a stretching phase and immediately enter the shortening phase. This is a different stimulus from a traditional box jump because of the eccentric loading; or stretching phase. The stretch stores energy in your legs and allows you to jump just a little bit higher.
Next up would be Seated box jumps. For these, sit on a bench with good posture and slightly rock back to pick your feet up off of the ground, then rock forward and jump! My coaching cues here are a) always think about limiting the amount of time that your feet are in contact with the ground and b) open your hips so they are fully extended. This variation requires that you jump through a greater range of motion, rather than slightly bending at the knees and hips. You have to execute the jump from what is basically the bottom of a squat (making it more challenging).
There are also Weighted box jumps that we can use to improve our jumping ability. There’s nothing tricky here: just jump with some weight. This could be a slam ball, barbell, weight vest, ankle weights, dumbbells, or even a plate. Asking your body to execute a jump with more than just body weight is probably the simplest way to change a stimulus. Just be careful when you do it and if you are unsure what to do, ask a coach!
Finally, we can implement Single leg box jumps. This is a valuable exercise because it will indicate if one leg is much more explosive than the other. For example, if you are easily able to jump to a height with one leg, but not the other, it is a reliable indicator that you heavily favor one leg. That may seem like its not a huge deal, but it could lead to an injury over time. I recommend starting with short heights/smaller boxes for this drill until you feel comfortable with landing on one leg. We are currently doing these in the Kingfield Strength class and it is clear that some lack the stability to land with one foot on a box without losing balance.
All of the variations above should be performed as an accessory exercise, totally separate from conditioning workouts. When we do box jumps in workouts, they are primarily placed in there to condition the legs, not develop explosive jumping power. Perform anywhere from 6-10 sets of 3-5 jumps twice a week and I promise you will be more explosive as a result.