What This App Is For
A timer for explosive plyometric training. It plays beeps at random intervals, and when you hear it, you explode into your jump or movement.
Get into position—in front of a box, in a squat, in a Bulgarian split squat stance. Wait. You don't know when the beep will come. When it does, explode with maximum power.
This is different from counting reps or using a metronome. When you know the timing, you pre-load and time jumps rather than truly reacting. Random intervals force genuine reactive power—the kind that transfers to sports.
Why Random Timing Works
With a set cadence, your nervous system learns the rhythm. After a few reps, you're timing jumps, not truly exploding on demand.
Random intervals break that pattern. Every rep requires genuine explosive initiation. You have to stay ready, stay loaded, then fire everything when the signal comes.
This is what happens in sports. A basketball player doesn't know when to jump for a rebound. Training with unpredictable timing builds the neuromuscular pathways for genuine reactive explosiveness.
The difference: Regular plyometrics build power. Random-timed plyometrics build reactive power—exploding on demand without anticipation.
Fake Beeps = Discipline
When enabled, the app occasionally plays a decoy sound. You're supposed to ignore it and NOT jump.
Explosive power without control is useless. If you bite on a fake in basketball, you get blown by. The ability to stay loaded and NOT fire is just as important as the ability to explode.
This builds inhibitory control—the discipline to suppress a response that's already starting to fire.
Pro tip: Start with obviously different sounds. As you improve, choose more similar sounds—that's where the real discipline training happens.
Why Audio Cues
Your auditory system processes signals 30-50ms faster than visual. That's why sports use starting guns, not lights.
Audio also lets you focus on form and position instead of staring at a screen. Set up your phone across the room, use earbuds, or a speaker.
Exercises
Any explosive movement where you can hold a ready position works well.
Box Jumps
Stand in front of the box in an athletic stance. Stay loaded and ready. When the beep hits, explode up onto the box. Step down, reset, wait for the next one.
Squat Jumps
Hold the bottom of a squat position. Keep tension in your legs. Beep = explode straight up with maximum height. Land soft, sink back down, hold, wait.
Bulgarian Split Squat Jumps
Rear foot elevated, front leg loaded. Hold the bottom position. On the beep, drive up explosively. Brutal because you're holding an unstable position.
Lunge Jumps
Hold a lunge position. On the beep, explode up and switch legs in the air. Land in the opposite lunge, hold, wait for the next signal.
Broad Jumps
Athletic stance, ready to launch forward. Beep = maximum horizontal explosion. Walk back, reset, hold your ready position, wait.
Tuck Jumps
Stand ready. On the beep, explode up and bring your knees to your chest. Land, absorb, reset to ready position, wait for the next one.
Depth Jumps
Stand on a box. On the beep, step off, hit the ground, and immediately explode up. Random timing means you can't anticipate—pure reactive power.
The Science
The neuroscience behind why random-interval training builds genuine reactive power.
Neural Drive Enhancement
Research shows 10-15% improvements in reaction time from neural adaptations, not just muscle changes.
- →Rate coding: Motor neurons fire faster, producing quicker force development.
- →Motor unit sync: Better coordination means less delay from "go" to movement.
- →Corticospinal excitability: The brain-to-muscle pathway gets stronger and faster.
Variable Foreperiod Effect
The "foreperiod" is wait time before a signal. When unpredictable, your nervous system can't time the response—it must actually detect and react.
This engages tonic alertness networks—brain systems maintaining sustained readiness rather than pulsed activation.
Inhibitory Control (Go/No-Go)
Fake beeps create Go/No-Go training—a technique used in cognitive neuroscience to strengthen executive function.
Related to Hick's Law: reaction time increases with choice complexity. Go/No-Go training improves discrimination speed and decision-making under pressure.
Why This Transfers to Sports
Variable practice creates contextual interference—harder during training, but better long-term retention and transfer to real situations.
How to Set Up Your Workout
- Choose your exercise — Box jumps, squat jumps, Bulgarian split squat jumps, whatever you're working on.
- Set your intervals — Min/max range determines how long between beeps. Longer = more holding. Shorter = rapid-fire.
- Set round duration — 30-60 seconds typical. Longer rounds = more cumulative fatigue.
- Set rest between rounds — Give yourself enough rest to maintain quality. 30-60 seconds minimum.
- Decide on fake beeps — Add them for discipline training, leave off for pure power focus.
- Hit start — After countdown, beeps come at random intervals. Explode on each one.
Recommended Settings
Power Focus
Maximum explosiveness, full recovery between reps.
Conditioning Focus
Building work capacity while staying explosive.
Mental Toughness
Longer holds, fake beeps, building wait-then-explode discipline.
Safety Notes
- •Warm up properly. Plyometrics are high-impact. Joints and muscles need to be ready.
- •Quality over quantity. When jumps get sloppy, the round is over—even if the timer isn't.
- •Solid landing surface. Stable box, non-slippery floor, enough space to land.
- •Progress gradually. Start with familiar exercises and moderate settings.
Ready to Train?
Pick your exercise, set your intervals, and start exploding on command.
Launch Plyo Timer