Depth jumps occupy a unique position in athletic training. They are simultaneously the most effective plyometric exercise for developing reactive strength and explosive power, and the exercise most likely to produce injury when misapplied. This combination of exceptional reward and genuine risk is what makes depth jumps simultaneously revered by elite strength and conditioning coaches and misused by athletes who apply them without understanding the demands they impose.
If you want the foundational depth jump technique guide, the depth jumps exercise article on this site covers form, box height selection, and basic programming in detail. This article goes deeper: the science behind why depth jumps work better than other plyometrics, how to integrate them into a complete periodisation plan, advanced programming for competitive athletes, and the specific errors that experienced athletes make that their beginners-guide reading would not have prepared them for.
Why Depth Jumps Are the Most Powerful Plyometric Exercise
The plyometric exercises available to athletes exist on a spectrum of demand and specificity. At one end are slow, low-demand exercises like standing broad jumps and box jumps. At the other end are depth jumps, drop jumps, and depth jump variations. The position of depth jumps at the demanding end of this spectrum is not arbitrary: it reflects the specific mechanism they train and how closely that mechanism matches the demands of high-speed athletic movement.
The stretch-shortening cycle spectrum:
All jumping and running movements involve the stretch-shortening cycle, where a muscle that is actively contracting is rapidly stretched and immediately shortens. The classification of SSC into slow (contact time greater than 250 milliseconds) and fast (contact time less than 250 milliseconds) is important because the two types involve different mechanisms and require different training to develop.
Most plyometric exercises train the slow SSC: countermovement jumps, box jumps, broad jumps, and medicine ball throws all involve relatively long amortisation phases where the muscles and tendons store and release energy over 300 to 500 milliseconds. These exercises are valuable and have a place in athletic training but they do not fully develop the fast SSC capacity that determines performance in sprinting, rapid direction changes, and high-frequency jumping.
Depth jumps specifically train the fast SSC because the drop from the box creates a landing velocity that challenges the neuromuscular system to respond within 150 to 250 milliseconds. The contact time constraint imposed by the box drop is not achievable through slow plyometrics because the athlete has no external force compelling rapid direction reversal.
The elastic energy advantage:
The elastic energy stored in tendons during the eccentric (loading) phase of a depth jump contact is significantly greater than in a countermovement jump performed from a stationary start. This is because the stored elastic energy is proportional to the velocity of the pre-stretch: a depth jump provides a rapid pre-stretch from the box drop velocity that a stationary start cannot replicate.
Research comparing depth jumps to countermovement jumps at matched jump heights consistently shows that depth jump training produces greater improvements in reactive strength, tendon stiffness, and fast SSC performance than countermovement jump training. This is the evidence base for the depth jump’s position as the most powerful plyometric exercise.
The Reactive Strength Index: Measuring Depth Jump Quality
The reactive strength index (RSI) is the quantitative measure of fast SSC quality and the primary metric for assessing depth jump performance and progress.
RSI calculation:
RSI = Jump height (metres) ÷ Ground contact time (seconds)
A depth jump that produces a 0.35-metre jump height with a 0.20-second contact time gives an RSI of:
0.35 ÷ 0.20 = 1.75
RSI benchmarks by athlete level:
- Recreational athletes: RSI 0.5 to 1.0
- Trained athletes: RSI 1.0 to 2.0
- Elite athletes: RSI 2.0 to 3.0
- World-class sprinters and jumpers: RSI above 3.0
Why RSI is more informative than jump height alone:
Two athletes can jump the same height from a depth jump but with very different contact times, producing very different RSI values. An athlete who jumps 0.35 metres with a 0.35-second contact (RSI 1.0) and an athlete who jumps 0.35 metres with a 0.20-second contact (RSI 1.75) have very different reactive strength qualities. The second athlete is significantly better at fast SSC performance despite identical jump height.
Practical RSI measurement:
Without laboratory equipment, RSI can be estimated using a smartphone app (such as My Jump 2 or Reactive Strength Index Calculator) that measures contact time and jump height from video analysis. This provides a practical field tool for tracking RSI development across a training programme.
Using RSI to guide box height:
The optimal box height for an individual is the height at which RSI is maximised. As box height increases, jump height initially increases (more elastic energy available) but contact time also increases (greater landing forces require more time to absorb). The optimal height is the point before contact time increases faster than jump height, maximising their ratio.
Practically, testing RSI at 30, 45, and 60 centimetres and identifying the height that produces the highest RSI value provides the most evidence-based box height selection.
Advanced Depth Jump Technique: Beyond the Basics
The depth jumps exercise article covers foundational technique. The following refinements are relevant for athletes who have mastered the basics and want to optimise their depth jump performance.
The swing-back technique:
Some elite coaches, particularly in sprint training, teach a swing-back arm action at the moment of ground contact, where the arms swing backward briefly before driving upward. This countermovement arm action loads the shoulder girdle and thoracic extensors eccentrically, allowing a more powerful concentric arm drive during the jump. This technique requires practice and is not appropriate for beginners.
Maintaining dorsiflexion control at contact:
Elite depth jumpers contact the ground with the ankle in a controlled position of approximately 5 to 10 degrees of dorsiflexion, not a fully plantarflexed or fully dorsiflexed position. This specific ankle position maximises the pre-stretch of the Achilles tendon and gastrocnemius while maintaining ankle stability. Athletes who contact with excessive plantarflexion reduce the Achilles tendon pre-stretch. Athletes who contact with excessive dorsiflexion increase the stress on the patellar and Achilles tendons without productive elastic energy storage.
Knee flexion at contact in speed-specific depth jumps:
In sprint-specific depth jump applications, some coaches cue a slightly more flexed knee position at contact than in vertical jump applications. This is because the sprint contact pattern involves more knee flexion than the pure vertical jump contact. The degree of knee flexion at contact should reflect the target athletic action.
The hip position during flight:
Elite performers in depth jumps maintain an extended hip position during the flight phase of the jump (the period between leaving the box and contacting the ground). This extended position places the hip flexors in a pre-stretched position that allows them to contribute to the landing absorption more effectively. Athletes who flex the hips during flight lose this pre-stretch advantage.
Depth Jumps in Plyometric Periodisation
Depth jumps should not be performed year-round. They are a high-intensity tool to be applied strategically within a periodised training plan. The following periodisation framework reflects best practice in elite strength and conditioning:
Phase 1: General preparation (6 to 8 weeks)
Foundation work that prepares the connective tissue and neuromuscular system for depth jump loading. No depth jumps in this phase.
Exercises: Box jumps, broad jumps, pogo jumps, ankle hops, bounding
Volume: 80 to 120 contacts per session, 2 sessions per week
Intensity: Low to moderate (bodyweight, low box heights)
Phase 2: Specific preparation (4 to 6 weeks)
Introduction of depth jumps at conservative box heights and volumes alongside continued general plyometrics.
Exercises: Depth jumps (30 to 40cm), lateral bound, single-leg hops
Volume: 60 to 80 contacts of depth jumps per session, 2 sessions per week
Intensity: Moderate
Phase 3: Intensification (4 to 6 weeks)
Primary depth jump development phase with increasing box heights and maintained or slightly reduced volume.
Exercises: Depth jumps (40 to 60cm), depth jump to sprint, single-leg depth jumps
Volume: 60 to 100 contacts per session, 2 to 3 sessions per week
Intensity: High
Phase 4: Competition/maintenance (ongoing)
Volume reduction with maintained intensity to preserve reactive strength adaptations without accumulated fatigue.
Exercises: Depth jumps (at individually optimal height) once per week
Volume: 30 to 50 contacts per session
Intensity: High
The key periodisation principle: Depth jump intensity (box height and RSI demand) should progress as general strength and slower plyometric foundations develop. Athletes who jump immediately to high box heights without the slower plyometric and strength base consistently show poor RSI values (deep knee bend, long contact times) and higher injury rates.
Research on Depth Jump Effectiveness
The evidence base for depth jumps is stronger than for most athletic training interventions. Key findings:
Sprint speed: Research by Markovic (2007) found that 6 weeks of depth jump training improved sprint speed by 1 to 3 percent in trained athletes. This may seem modest, but at the elite level where marginal gains are the currency of competition, a 1 to 3 percent sprint speed improvement is substantial.
Jump height: Multiple studies have found depth jump training improves vertical jump height by 3 to 10 percent over 6 to 12 week training blocks. Larger improvements tend to occur in less trained athletes, smaller improvements in already well-trained athletes.
Running economy: As covered in the running economy article on this site, plyometric training including depth jumps improves running economy by 2 to 4 percent through increased tendon stiffness and improved neuromuscular coordination.
Tendon stiffness: Research using ultrasound elastography has found significant increases in Achilles tendon stiffness following depth jump training programmes, confirming the mechanical mechanism of improvement.
Comparison with other plyometrics: Research directly comparing depth jump training to other plyometric modalities consistently finds depth jumps produce greater improvements in reactive strength indices and fast SSC performance, though the advantage is smaller for slow SSC measures like countermovement jump height.
Advanced Programming for Competitive Athletes
The following programmes reflect the depth jump application used in elite sport strength and conditioning.
Programme for sprint athletes (pre-season, 8 weeks):
Weeks 1 to 2: Foundation
- Session A: Depth jumps 3 x 5 (40cm), pogo jumps 3 x 15, bounding 3 x 30m
- Session B: Box jumps 4 x 5 (maximum height), broad jumps 4 x 4
- Frequency: 2 sessions per week
Weeks 3 to 4: Build
- Session A: Depth jumps 4 x 5 (50cm), depth jump to sprint 3 x 3, single-leg bounds 3 x 20m
- Session B: Depth jumps 3 x 5 (45cm), bounding 4 x 30m
- Frequency: 2 sessions per week
Weeks 5 to 6: Intensify
- Session A: Depth jumps 4 x 6 (55 to 60cm), depth jump to sprint 4 x 3
- Session B: Single-leg depth jumps 3 x 4 per leg (30cm), reactive agility depth jumps 3 x 4
- Frequency: 2 to 3 sessions per week
Weeks 7 to 8: Peak
- Session A: Depth jumps 5 x 5 (60cm), reactive sprint starts 5 x 20m
- Session B: Depth jumps 3 x 4 (55cm), bounding 3 x 40m
- Frequency: 2 sessions per week
Programme for team sport athletes (off-season, 6 weeks):
Weeks 1 to 2:
- Depth jumps 3 x 5 (35 to 40cm), 2 sessions per week
- Lateral depth jumps 3 x 4 per side (30cm)
- Volume: 50 to 60 contacts per session
Weeks 3 to 4:
- Depth jumps 4 x 5 (40 to 50cm), 2 sessions per week
- Lateral depth jumps 3 x 5 per side (35cm)
- Depth jump to change of direction 3 x 4
- Volume: 65 to 80 contacts per session
Weeks 5 to 6:
- Depth jumps 4 x 6 (50 to 55cm), 2 sessions per week
- Single-leg depth jumps 3 x 4 per leg (30cm)
- Volume: 70 to 90 contacts per session
Programme for vertical jump sports (volleyball, basketball, 8 weeks):
Emphasis: Maximum RSI development, vertical jump height
Weeks 1 to 2: Depth jumps 3 x 5 (35cm), emphasise maximum jump height
Weeks 3 to 4: Depth jumps 4 x 5 (45cm), RSI tracking each session
Weeks 5 to 6: Depth jumps 4 x 6 (55cm), continuous depth jumps 2 x 4 contacts
Weeks 7 to 8: Depth jumps 5 x 5 (60cm), single-leg depth jumps 3 x 4 per leg
Common Errors in Experienced Athletes
The depth jumps exercise article covers beginner errors. The following errors are specific to athletes who have basic depth jump competency but have developed problematic habits:
Progressively increasing box height without tracking RSI: Many athletes increase box height indefinitely under the assumption that higher is better. Without RSI tracking, they cannot identify when the box height has exceeded the optimal and contact time has increased enough to reduce the reactive training stimulus.
Performing depth jumps too early in a session after fatigue: Experienced athletes often incorporate depth jumps into circuit training or perform them after heavy strength work. Depth jumps require maximum neuromuscular freshness to achieve the contact times that provide a fast SSC stimulus.
Not allowing adequate recovery between reps: Taking the next rep before full recovery produces accumulated contact time increases within a set. Each rep should feel as explosive as the first. Walking back to the box and pausing for 20 to 30 seconds between reps allows adequate neuromuscular recovery.
Using depth jumps year-round: Athletes who include depth jumps in every training block without periodised phases of lower-intensity plyometrics accumulate connective tissue stress that reduces rather than builds tendon stiffness and increases patellar and Achilles tendon injury risk.
Neglecting single-leg work: Most athletic actions are unilateral. Athletes who only perform bilateral depth jumps develop reactive strength in a bilateral pattern that does not fully transfer to the unilateral demands of sprinting, jumping off one leg, and direction changes. Including single-leg depth jump variations is essential for competitive athletes.
Frequently Asked Questions
Are depth jumps safe for young athletes?
Research indicates that depth jumps are safe for adolescent athletes who have adequate strength foundations and are coached with appropriate progressions. The American College of Sports Medicine supports plyometric training including depth jumps for youth athletes when supervised and progressively implemented. The key prerequisites are adequate relative strength, sound landing mechanics, and conservative initial box heights of 30 centimetres or less.
How do depth jumps compare to weighted jump squats for power development?
Both develop jumping power but through different mechanisms. Weighted jump squats develop the slow SSC and the concentric power of the lower body. Depth jumps develop the fast SSC and reactive strength specifically. Research suggests that combining both approaches produces better overall power development than either alone. In a periodised plan, weighted jump squats fit in the general preparation phase and depth jumps in the specific preparation and intensification phases.
Can depth jumps be done without a box?
A depth jump requires an elevated starting position to provide the pre-stretch velocity of the drop. Without a box, the exercise becomes a drop jump from a step or a countermovement jump, which are different exercises with different training stimuli. If a box is not available, drop jumps from a step of 20 to 30 centimetres provide a partial fast SSC stimulus that is better than no reactive training.
Should I land on the same spot I take off from?
Yes. Landing on the same spot or very close to it maximises the vertical orientation of the ground reaction force, which produces the most efficient elastic energy storage and return. Landing significantly forward of the take-off point changes the mechanics toward a broad jump pattern and away from the vertical reactive training stimulus.
How do I know if depth jumps are working?
Track RSI using a smartphone app every 2 to 3 weeks during a training block. Improving RSI (higher jump height at the same or shorter contact time) confirms the training is producing the target adaptations. Additionally, improvements in sprint times over 10 to 30 metres, increased vertical jump height, and subjectively feeling more explosive during sport-specific actions all indicate effective depth jump adaptations.