What is Depth Jump?

What is Depth Jump?

A depth jump is a plyometric exercise in which you step off an elevated box or platform, let gravity pull you down to the floor, and rebound into a maximal vertical jump the instant you land. Soviet sports scientist Yuri Verkhoshansky developed it in the late 1960s as the centerpiece of what he called the shock method, training athletes to absorb a sudden eccentric load and convert it into concentric force almost instantly. American coach Fred Wilt later watched Soviet athletes perform these drills and coined the umbrella term plyometrics to describe them. A depth jump is not the same drill as a box jump. A box jump asks you to jump up onto an elevated surface, a pure concentric effort with no eccentric loading demand. A depth jump asks you to come down off the box first, so the muscle-tendon unit must absorb the landing and rebound before you ever leave the ground again. That downward-then-upward sequence is what makes the depth jump one of the most intense plyometric drills in a strength coach's toolkit, and why it sits near the top of most plyometric progressions, used only once an athlete already handles box jumps, countermovement jumps, and squat jumps comfortably. Coaches program it specifically to sharpen reactive strength: the ability to reverse a fast eccentric stretch into a powerful concentric contraction in a fraction of a second, a quality that transfers directly to sprinting, cutting, and jumping in sport.

How it works

A depth jump works by driving the stretch-shortening cycle (SSC) as hard and as fast as possible. When you land, the gastrocnemius, soleus, quadriceps, and gluteus maximus all lengthen eccentrically in a fraction of a second, and the Achilles and patellar tendons store elastic energy the way a stretched rubber band does. At the same time, muscle spindles in the loaded muscles detect the rapid stretch and fire a reflexive signal back to the same muscle, a myotatic stretch reflex that adds extra neural drive on top of the stored elastic energy. The shorter the gap between landing and takeoff, called the amortization phase, the more of that stored energy converts into upward force rather than leaking away as heat and joint compression. Verkhoshansky's original standard for a true depth jump was a ground contact time of roughly 0.1 to 0.2 seconds; research classifies anything under about 0.25 seconds as a fast SSC and anything slower as a slow SSC that behaves more like a squat jump with an extra step. Ground reaction forces during a depth jump are among the highest seen in plyometric training, which is exactly why the drill builds tendon stiffness and rate of force development so effectively, and exactly why it demands a higher strength and landing-mechanics prerequisite than a standard box jump or vertical jump.

The formula

Reactive Strength Index (RSI) = jump height ÷ ground contact time

A ground contact time under 0.25 seconds marks a fast SSC and a genuine depth jump; Verkhoshansky's original standard was tighter still, 0.1 to 0.2 seconds. Track RSI, not just jump height, to judge whether a box height is actually training reactive strength.

How to apply it

• Pick the box height with an RSI test, not a guess: Test a few heights, say 30, 45, and 60 cm, and calculate jump height divided by ground contact time at each. Train at the height that produces the highest RSI, which research shows is often lower than athletes assume.
• Step off, never jump off: Step off the box so gravity alone determines the drop; jumping off adds upward velocity that changes the loading and makes the drop height inconsistent from rep to rep, corrupting both the training stimulus and any RSI data you collect.
• Land on the balls of the feet and stay stiff: Land with a slight, fixed knee bend rather than sinking deep, and cue yourself to leave the ground as fast as possible. This shortens the amortization phase, though research shows it also raises peak impact force by roughly 20 percent, so build up to it gradually.
• Drive a full triple extension on the rebound: The instant your foot contacts the ground, extend the ankles, knees, and hips together to redirect the stored elastic energy upward. A sloppy, sequential extension bleeds off force and lengthens ground contact time.
• Cap volume and rest fully between sets: Keep sessions to roughly 3 to 6 sets of 3 to 6 reps with 2 to 3 minutes of rest between sets. Depth jumps are a maximal-intensity drill; once contact time or jump height drops off, stop the set.
• Meet the strength prerequisite first: A widely cited NSCA guideline calls for a back squat at or above 1.5 times bodyweight, solid single-leg control, and a foundation of box jumps and countermovement jumps before adding depth jumps to a program.

Types

Worked example

One way to find your own best box height is to test reactive strength index (RSI), jump height divided by ground contact time, across a range of drop heights, then train at whichever height produces the highest number rather than the tallest box you can survive.

RSI peaks at 30 cm here even though jump height is a hair better off the 45 cm box; the extra 0.02 seconds of ground contact is exactly the shift research flags as the point where a depth jump stops training a fast SSC and starts training a slower, less reactive pattern. Re-test every few weeks; as reactive strength improves, the optimal height usually rises with it.

Depth jump vs box jump

Both are plyometrics, but they load the stretch-shortening cycle differently: a depth jump asks the tendon and muscle to absorb a fall and rebound in a fraction of a second, while a box jump only asks you to produce force upward and land soft. Program depth jumps for reactive strength once a base of box jumps and countermovement jumps is already solid.

By goal

• Team-sport and reactive-power athletes (basketball, volleyball, sprinters): Program depth jumps twice a week, 3 to 5 sets of 4 to 6 reps at the box height with your best RSI, with a full 2 to 3 minute rest between sets, and cue leaving the ground as fast as possible on every rep.
• General strength and hypertrophy lifters: Depth jumps aren't necessary for most physique or strength goals. Box jumps and countermovement jumps deliver most of the power carryover with far less joint stress; if you include depth jumps at all, keep the box low, 30 to 45 cm, and volume light.
• Return-to-play and rehab: Rebuild single-leg strength and stick-landing mechanics first. Start with a drop-and-stick landing from a low box with no rebound, and only add the reactive re-jump once landing control is consistent and pain-free.

Common misconceptions

• "A depth jump and a box jump are the same thing." A box jump is jumping up onto an elevated surface, a pure concentric effort. A depth jump is stepping down off an elevated surface first, so the legs must absorb a fall and rebound instantly. Confusing the two changes the training stimulus entirely.
• "A higher box always produces better results." Research on optimal drop height shows the ideal box is individual and often lower than assumed, commonly 30 to 45 cm for many athletes. Past an athlete's reactive capacity, a taller box only increases ground contact time and impact force without raising RSI.
• "You should jump off the box, not step off it." Jumping off adds extra downward velocity that changes the loading and makes the drop height inconsistent rep to rep. Verkhoshansky's method, and NSCA coaching guidance, both call for stepping off so gravity alone sets the fall.
• "Depth jumps are safe for anyone who is plyometric-ready." Ground reaction forces during a depth jump are among the highest in plyometric training, so they demand more than general plyometric readiness. A commonly cited prerequisite is a back squat at or above 1.5 times bodyweight plus solid single-leg control before adding them.

Related terms

Depth Jump FAQ

What is a depth jump used for?

A depth jump trains reactive strength, the ability to absorb a fast eccentric landing and reverse it into a powerful concentric jump in a fraction of a second. Coaches program it to raise rate of force development, tendon stiffness, and vertical jump height in athletes who sprint, cut, or jump in their sport.

What is the difference between a depth jump and a box jump?

A box jump is jumping up onto an elevated surface, a purely concentric effort. A depth jump is stepping down off an elevated surface first, so the legs must absorb the landing and rebound instantly. That eccentric-to-concentric sequence makes the depth jump a far more advanced, higher-force plyometric drill.

Is a depth jump the same as a drop jump?

In most training and research literature the terms are used interchangeably for the same step-off, land, and rebound movement. Some coaches, following Verkhoshansky, reserve depth jump for the trained rebound version and drop jump for the minimal-knee-flexion version used to test reactive strength index in a lab or gym setting.

How high should the box be for a depth jump?

Research finds optimal drop heights are individual, commonly landing between 30 and 60 cm (12 to 24 in), occasionally up to 75 cm for well-trained jumpers. Test reactive strength index at a few heights and train at whichever produces the highest number, not the tallest box you can survive.

How do you calculate reactive strength index from a depth jump?

Divide jump height by ground contact time: RSI equals jump height divided by ground contact time. A higher RSI means you are converting the landing into upward force faster and more efficiently. Coaches use it to individualize box height and track whether reactive strength is improving over a training block.

Are depth jumps bad for your knees?

Depth jumps produce some of the highest ground reaction forces in plyometric training, so they carry real impact stress if a lifter isn't prepared for them. Built on adequate strength, landing mechanics, and a conservative box height, they are a standard, well-studied training tool rather than an inherently unsafe one.

How many depth jumps should I do in a workout?

Most programs keep depth jumps to 3 to 6 sets of 3 to 6 reps, with 2 to 3 minutes of full rest between sets, because the drill is maximal intensity rather than a conditioning exercise. Stop the set the moment jump height or contact time visibly drops off.

How strong do you need to be before doing depth jumps?

A widely cited NSCA guideline calls for a back squat at or above 1.5 times bodyweight, along with solid single-leg balance and control, before adding depth jumps. Athletes should also already handle box jumps and countermovement jumps cleanly, since depth jumps sit near the top of the plyometric progression.

Do depth jumps actually increase vertical jump height?

A meta-analysis pooling plyometric training studies found drop-jump-based training produced roughly a 4.7 percent improvement in drop jump height, alongside larger gains in countermovement jump, when added to a training program over several weeks. Gains depend on starting reactive strength, box height, and how consistently the drill is trained.

What muscles does a depth jump work?

The gastrocnemius, soleus, quadriceps, and gluteus maximus absorb the landing eccentrically and then drive the rebound concentrically, while the Achilles and patellar tendons store and return elastic energy. The hamstrings and core also contract isometrically to keep the landing stable and the trunk upright through the whole movement.

References

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3. Byrne PJ, Moran K, Rankin P, Kinsella S. A comparison of methods used to identify 'optimal' drop height for early phase adaptations in depth jump training. J Strength Cond Res, 2010. PubMed 20634738
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7. Plyometrics. Wikipedia