Stepping off a box shouldn't just be reserved for your local step aerobics class. With a few minor upgrades, box step-offs can be an effective way to add some frontal plane (side-to-side) loading to your leg day. Not only can they add another direction to your training, but they transfer over well to athletics and they're a damned effective muscle-builder too.
Lots of Ways to Do Them
Box step-offs are somewhere in between a lateral lunge and a squat, while the addition of a box takes you further into deficit. The height of the box and degree of deficit are up to you. For those that don't want much extra range of motion, stepping off a 45-pound plate might be enough.
Conversely, for those that want a deep deficit, setting a box and some risers up to knee height would have its advantages.
A single dumbbell in the offside hand works great, but most seem to prefer the feel of a kettlebell. This variation is a good starting point for many and allows some respectable loading for even the strongest lifter. It's not uncommon for someone to get to the point where they can use a third of their bodyweight in one hand.
Other effective ways to load step-offs are in a goblet position, front rack position, or with a landmine bar.
The landmine can provide an element of stability to the exercise, as it's one of the most comfortable variations (if you get the setup right). It can be held in the offside hand or in both.
A cable seems to work okay too. For complete beginners, a medicine ball or even body weight are just fine to start off with. Just make sure you respect the movement with these rules:
1. A Deficit is for a Deficit
Far too many times you see those using a raised platform stop before actually getting into the deficit. The point of a deficit is to increase range of motion.
Unless you're doing a goblet squat, EZ-bar front squat, or are a beginner stepping of a 45-pound plate, the implement you're using needs to drop below the top of whatever you're standing on, thus taking you into a deficit! If it doesn't, then there's not really much use for the extra height.
2. Put on the Brake
As you step sideways off the box, there's a "braking effect" happening. The offside leg must step off and absorb the impact forces through the abductors, quadriceps, and glutes. This braking effect is a form of eccentric overload, and eccentric overload is good for building muscle.
3. Lean With a Purpose
Depending on how you hold the weight, distribution of load and body position change. You can have a more upright torso by using a goblet position or front rack, or slightly more forward-leaning torso with a weight hanging in front.
You can even emphasize a forward lean and get even greater hip dominance. Just focus on pushing your butt back more as if you were showing it off to the person behind you.
To target the offside leg, hold the weight on that same side of the body. We're not talking a massive change here, but when the weight is held in one hand, load is shifted away from the nearside leg towards the offside, meaning that as you're stepping off, the brakes need to work a little harder.
That means more eccentric overload on the abductors, glutes, and quads on the offside leg. There tends to be a bigger forward lean in one-handed variations too.
Whichever way you perform box step-offs, it's the combined lateral braking motion and increased hip and knee range of motion that makes this exercise so effective.
The decision you need to make is whether you want to load the braking side more (emphasizing the eccentric overload), or if your focus is loading more through increased stretch and range of motion on the nearside leg.
Both can be great triggers of muscle growth as well as have carry-over advantages to sport. Pick your weight, sets and reps based on these goals, although generally 2-4 sets of 8-15 reps each side work best.