Plyometric drills can be organized by two levers that drive adaptation: vertical displacement (how high you go) and ground contact time (how fast you get off the floor). In sport science, actions with very short contacts are often called fast stretch-shortening cycle (SSC), and those with longer contacts are slow SSC. A widely used (and recently re-examined) threshold is ~250 ms: contacts <250 ms behave like fast SSC; >250 ms behave like slow SSC.
Our Plyometric Quadrant maps drills into four zones:
- 🔵 High Reactivity (fast contact + high vertical)
- 🔴 High Vertical / Slow Contact
- 🟢 Fast Contact / Low Vertical
- 🟡 Low Vertical / Slow Contact
Below, each zone includes what it trains, example drills, coaching cues, programming ranges, and key caveats—grounded in the work of Eamonn Flanagan & Thomas Comyns, Yuri & Natalia Verkhoshansky, and contemporary research.
🔵 High Reactivity (Blue): Fast Contacts + High Output
What it trains. Maximal use of the fast SSC: tendon-dominant energy storage/release, stiffness, and rapid force transmission. Expect very short GCTs (<250 ms) and high RSI (flight time ÷ contact time).
Typical drills.
- Drop jumps targeting minimal GCT and high rebound (not “depth jumps” in the Verkhoshansky sense).
- High-threshold pogos and fast bounds.
- Max-velocity sprint flys/accelerations (fast SSC dominant).
How to coach it.
- Cue “hit and go”: stiff ankle, quiet ground, tall posture.
- Measure GCT/RSI when possible to ensure you’re actually in the fast SSC zone.
Programming ranges.
- Low volume, high intent: 3–5 sets × 3–5 contacts; long rests (≥2–3 min).
- Use after a thorough strength base and progress from low box heights.
Caveats.
- Quality drops rapidly with fatigue; watch RSI drift.
- Box height should be individualized; higher is not always better for RSI or tissue stress.
🔴 High Vertical / Slow Contact (Red): Big Heights, Longer Contacts
What it trains. Explosive force-dominant outputs where SSC coupling is slower. Useful for bridging heavy strength work to true “bounce” qualities.
Typical drills.
- Depth jumps in the Verkhoshansky “shock method” sense (optimize rebound height, not minimal contact).
- Loaded squat jumps (BB/Hex bar), single-leg vertical jumps, continuous vertical jumps.
How to coach it.
- Outcome target (e.g., basketball rim, Vertex) to drive max rebound height.
- Emphasize countermovement timing and full hip-knee-ankle extension.
Programming ranges.
- Moderate volumes: 3–5 sets × 3–6 reps (loaded SJ ~20–30% BW is a common power zone).
- For depth jumps in a shock block, keep volume concentrated but controlled; monitor landing quality and asymmetry.
Caveats.
- Shock-method depth jumps are high stress; prerequisites (strength, landing mechanics) matter and progressions should be conservative.
🟢 Fast Contact / Low Vertical (Green): Rhythm, Stiffness, Mechanics
What it trains. Neural rhythm, ankle/knee stiffness, and posture at high step rates with short contacts but modest displacement—great for sprint mechanics and “bounciness.”
Typical drills.
- Pogo series (bilateral & unilateral), quick hops in place, rudiment series.
- Speed box touches (low box, rapid contacts), A-skips/high-knees (fast SSC exposures).
How to coach it.
- Cadence and posture first; keep ranges small and rhythmic.
- Use as primers between sprints or lifts.
Programming ranges.
- Can be used frequently: 2–4 sets × 8–15 contacts or 10–20 s bouts; minimal fatigue.
Caveats.
- Surfaces matter: softer surfaces lengthen GCT and blunt the reactive benefit; choose firm ground when training fast SSC.
🟡 Low Vertical / Slow Contact (Yellow): Landing Skill, Eccentric Control, Capacity
What it trains. Foundational skills—braking control, posture, alignment, and tissue capacity—with longer contacts and small displacements. Essential for youth, return-to-train, and deload phases.
Typical drills.
- Depth drops (stick), squat jumps (sub-max), march-to-skip progressions, rope skipping at easy tempos, slow SL hops.
How to coach it.
- Quiet, controlled landings; knees track, hips back, stacked torso.
- Build tolerance before advancing to faster SSC exposures.
Programming ranges.
- 3–5 sets × 3–5 reps depth drops; 2–3 min total rope blocks; low-to-moderate weekly exposure.
Caveats.
- Don’t live here with advanced athletes—use it to prepare or restore, then progress to faster contacts.
Why 250 ms Matters (and Its Limits)
Flanagan & Comyns popularized using contact time and RSI to steer plyometric loading toward fast SSC outcomes, with ≈250 ms a practical threshold for “reactive” work. Recent scholarship notes that 250 ms is a useful heuristic, but the “true” boundary varies by task, surface, and athlete (age, strength, tendon properties). Treat 250 ms as context-dependent, not absolute.
Programming by Athlete & Season
All four zones are useful—the art is choosing them for the right reasons.
- Youth / novices. Start in 🟡 to master landings and tissue capacity; layer in 🟢 for rhythm and stiffness; add 🔴/🔵 only after fundamentals mature (youth SSC characteristics evolve across maturation).
- Strength emphasis (off-season). Favor 🔴 to convert strength to vertical power; keep a thread of 🟢 for mechanics.
- Speed/power emphasis (pre-season, in-season). Prioritize 🔵 and 🟢 with low fatigue exposures; monitor RSI and contact time to confirm training intent.
- Shock blocks & depth jumps. Reserve for prepared athletes; individualize drop height, constrain volume, and ensure rebounds are truly maximal (not just fast).
Practical Measurement & Surfaces
- Measure what you target. If the goal is reactivity, verify GCT <250 ms and track RSI (jump mats/force plates/wearables).
- Surface choice. Firmer surfaces shorten contact time and favor fast SSC; softer surfaces lengthen it—use this deliberately.
- Drop height matters. RSI and joint loading both change with box height; “higher” is not automatically “better.” Progress with outcomes (RSI, rebound height) as your guide.
Final Takeaways
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Use the quadrant for clarity, not hierarchy. Every zone has value when matched to the athlete, phase, and objective. 2) Confirm intent with data (GCT, RSI, rebound height). 3) Respect the shock method—it’s potent and demanding. 4) Progress across zones: build skill and capacity (🟡) → stiffness and rhythm (🟢) → force & vertical power (🔴) → high reactivity (🔵).