PLYOMETRICS
What Is Plyometrics? A Safe Starting Guide
The stretch-shortening cycle explained, fast vs slow SSC, the NSCA entry criteria and low-intensity progressions for beginners.
Plyometrics are exercises that use the stretch-shortening cycle (SSC): an eccentric landing or dip, a brief isometric transition, then a concentric explosion. They are the most direct way to train vertical jump power — and the easiest to get wrong.
This guide covers what the SSC actually is and, more importantly, whether you are ready to start.
The stretch-shortening cycle
When a muscle is stretched quickly and immediately shortens, it produces more force than a pure concentric contraction. That extra output comes from stored elastic energy and the stretch reflex, and it is exactly what jumping depends on.
Fast and slow SSC are both trainable
Fast SSC movements have ground contact under 0.25 seconds (depth jumps, reactive hops); slow SSC movements last longer (box jumps, countermovement jumps). Jump athletes need both — fast SSC builds reactive power, slow SSC builds the ability to absorb and redirect force.
The NSCA entry criteria
High-intensity plyometrics load the body with impact forces, so the strength base comes first:
- Squat at least 1.5x bodyweight — enough strength to absorb impact.
- No acute lower-limb injury history, especially Achilles, patellar or ACL.
- At least 3 months of systematic strength training.
- A clean depth drop from 30 cm with a stable, quiet landing.
Not ready yet? Start low
If you do not meet the criteria, that does not mean no jumping — it means start low. Pogo jumps, low box jumps, ladder drills and landing practice build the same qualities with a fraction of the impact load while you develop the strength base.
Key takeaways
- Plyometrics train the stretch-shortening cycle, the engine of jumping.
- Fast and slow SSC movements are both needed.
- Meet the strength and injury-history criteria before high-intensity work.
- Beginners should start with low-intensity plyometrics, not depth jumps.
References
- NSCA Essentials of Strength Training and Conditioning (4th ed.), Ch. 18
- Verkhoshansky & Siff (2009) Supertraining, Ch. 6
Keep reading
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How Long Until You See Results From Jump Training?
A realistic vertical jump improvement timeline: what changes at 2, 4, 8 and 12 weeks, and why starting level, training quality and recovery decide the pace.
TRAINING METHODS
How Many Jump Training Sessions Per Week Do You Actually Need?
Training frequency by experience level, safe plyometric contact volume, and the warning signs that tell you to cut back.
TRAINING PROGRESS
How to Break a Jump Training Plateau
A plateau means the body has adapted to the current stimulus. Diagnose the weak link, change the variables, deload and fix recovery.