Box Jump
Primary muscles: Quadriceps · Glutes · Calves · Core
Overview
The box jump is a core plyometric exercise in CrossFit for developing explosive lower-body power. It may look like a simple jump from the floor onto a box, but it is a highly technical movement that trains the nervous system's maximum recruitment ability and the ability to absorb impact on landing at the same time.
A box jump begins by standing about a shoulder-width distance from the box. Using an active arm swing can increase jump height by up to 20–30%. Perform a countermovement — swinging the arms back while bending the knees — and then swing the arms forward as you jump explosively.
In the air, pull the knees up toward the chest to make room for the feet to land on the box. The most important part of landing is a "soft landing": the whole foot lands on the box and the knees bend to absorb the impact. Landing with straight legs sends a great deal of shock into the joints.
There are two ways to come down: step down and jump down. When doing many reps in a WOD, stepping down is recommended to protect the Achilles tendon. Achilles ruptures from repeated jump-downs under fatigue are among the most common CrossFit injuries, so extra care is needed.
The CrossFit RX box height is 24 inches (about 61 cm) for men and 20 inches (about 51 cm) for women.
Step-by-step
Starting position
Stand a shoulder-width distance from the box with the feet shoulder-width apart.
Countermovement
Swing the arms back and bend the knees to prepare for the jump.
Explosive jump
Swing the arms forward and drive hard through the floor to jump as high as possible.
Soft landing
Land with the whole foot on the box, bending the knees and hips to absorb the impact.
Finish and descend
Fully extend the hips, then step down from the box.
Technical Standards
Take off from both feet at once, using an arm swing to maximize jump power
Pull the knees toward the chest in the air to clear the box
Land on the box with both feet at the same time, whole foot on the box
Bend the knees and hips on landing to absorb impact (soft landing)
Finish with full hip extension on top of the box
Step down when coming off the box (recommended for high rep counts)
Common Faults
Hard landing: landing with straight knees greatly increases joint impact
Landing on the toes instead of the whole foot: unstable and overloads the Achilles tendon
No hip extension on top: coming straight down after landing misses completing the movement
No arm swing: lower jump height risks hitting the shins on the box edge
Scaling
Step-up — stepping onto the box one foot at a time builds leg strength and balance. Start with a 20–30 cm box height.
Lower box jump or plate jump — master landing technique on a box 10–20 cm lower, then raise the height gradually.
Depth jump or single-leg box jump — drop from a higher box and rebound into an immediate jump, or perform advanced variations on one leg.