COMMON MYTHS
Is Jump Height Genetic? (Can It Be Trained?)
Genetics explain roughly 40–60% of jump variance — which means 40–60% is training. And untrained athletes can nearly double their jump.
'I was born unable to jump' is one of the most harmful misconceptions in athletics — because it stops people before they start.
The variance split
Genetics explain roughly 40–60% of CMJ variance, meaning 40–60% is determined by environment and training. Even genetically fixed fast-twitch ratios can be optimized.
The real-world range
An untrained person jumps roughly 30–40 cm. One to two years of systematic training reaches 50–70 cm — nearly double. That gain is training, not genetics.
What is actually locked in
Fiber I/II ratios, limb proportions and tendon attachment points explain only a small share of variance. If you have not trained systematically for 2+ years, you do not know your ceiling yet.
Key takeaways
- Half of jump variance is trainable.
- Untrained jumpers can nearly double their height.
- Train first — talk about ceilings after 2+ systematic years.
References
- Bouchard et al. (2011) J Appl Physiol
- Yang et al. (2003) Am J Hum Genet
- Verkhoshansky & Siff (2009) Supertraining, Ch. 2
Keep reading
TRAINING PROGRESS
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.