Volleyball approach analysis

Jump higher, hit harder

Film one spike approach from the side. Stat Jump scores every part of it out of 10, so you know exactly what to fix.

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A player runs a spike approach and jumps next to the net while Stat Jump tracks their body with a skeleton overlay. Labels appear at each moment: approach speed 10.4 mph, penultimate step 0.40 seconds, plant contact 0.24 seconds, deepest knee bend 119 degrees, vertical 26.8 inches, touch height 10 feet 0 inches, and hang time. It ends on the score card: overall 7.8 out of 10, with vertical 7.1, touch height 7.2, ground contact 10.0, arm swing 7.8, knee bend 8.7, penultimate step 8.3 and approach 6.3.

Credit: Donald Hui

How it works

Your approach, scored in 3 steps

  1. Film one approach

    A friend holds the phone, or it sits on a tripod, 10 to 15 feet from the side of your approach at head height. Record at 60fps.

  2. Tell it about you

    Your height, hitting hand and level. Your height is the ruler: it turns the video into real distances.

  3. Get your scores

    Every part of the approach is scored out of 10, plus an overall score, so you know exactly what to work on.

Same video, same score

Analyze the same clip twice and you get the same result, every time. Progress you see is real progress.

All on your phone

The analysis runs entirely on your device. Your video never leaves your phone.

Scored for your level

Youth to elite. Jump height is judged against your level, while technique is judged the same for everyone.

What it measures

Seven scores from one approach

Each part is scored out of 10 and rolled into an overall score.

Estimated vertical

Jump height, from flight time and hip rise.

Touch height

How far you reach above the net.

Ground contact time

How long your final plant takes.

Arm swing

Backswing range and timing, forward swing, bow-and-arrow.

Knee bend and load

Depth, trunk lean and timing of the plant.

Penultimate step

Length, rhythm, hip lowering and a heel-first plant.

Approach

Footwork pattern, speed build-up, and habits like a bunny hop or stutter step.

How each score is worked out

Every score is out of 10. Under each part are the measurements that earn a given score. Anything in between scores proportionally, and anything past the ends gets the end score.

These only change the targets marked Set by level. Technique targets are the same for everyone.

Estimated vertical15% of overall

Jump height, from your time in the air, checked against how far your hips rise.

  • Jump heightSet by level

    Higher is better.

    • Score 2 at 8.9 in
    • Score 4 at 13.3 in
    • Score 6 at 17.7 in
    • Score 8 at 22.1 in
    • Score 10 at 26.6 in
Touch height15% of overall

How far above the net you reach: your standing reach plus your vertical.

  • Reach above the netSet by level

    Higher is better.

    • Score 1 at 0 in
    • Score 3 at 5.9 in
    • Score 5 at 11.8 in
    • Score 7 at 17.7 in
    • Score 9 at 23.6 in
    • Score 10 at 29.5 in
Ground contact time10% of overall

How quickly your final plant turns into the jump.

  • Plant contact time60% of this score

    From your first plant foot landing to your last toe leaving the ground. Shorter is better.

    • Score 10 at 0.25 s
    • Score 6 at 0.33 s
    • Score 2 at 0.45 s
  • Foot stagger20% of this score

    The gap between your two plant feet landing. A small gap is best.

    • Score 6 at 0 s
    • Score 10 at 0.03 s–0.12 s
    • Score 6 at 0.2 s
    • Score 2 at 0.3 s
  • Jump efficiency20% of this scoreSet by level

    Your vertical in meters divided by your contact time in seconds. Higher is better.

    • Score 2 at 0.6
    • Score 6 at 1.2
    • Score 10 at 1.95

If your deepest knee angle is over 140° and your vertical scores under 5, this score is capped at 6: a quick plant from a shallow bend is not an efficient one.

Arm swing15% of overall

How much your arms add to the jump, and how ready you are to hit at the top.

  • Backswing range25% of this score

    How far your arms swing back behind your body.

    • Score 2 at 0°
    • Score 6 at 30°
    • Score 10 at 60°
  • Backswing timing25% of this score

    How close your arms reach their furthest-back point to your plant foot landing.

    • Score 10 at 0.05 s
    • Score 6 at 0.15 s
    • Score 2 at 0.3 s
  • Forward swing25% of this score

    How high your wrists are above your shoulders as you leave the ground.

    • Score 2 at −0.5 arm lengths
    • Score 6 at level
    • Score 10 at +0.5 arm lengths
  • Bow-and-arrow25% of this score

    Your arm position at the top of the jump.

    Up to 6 points when your hitting elbow is at or above shoulder height and drawn back (3 if only one of the two), plus up to 4 points for raising your other arm 45° or more above horizontal.

Knee bend and load15% of overall

How you load into the plant: depth, timing and posture.

  • Deepest knee angle45% of this score

    The tightest your knee bends in the plant (180° is a straight leg). Too deep and too shallow both cost points.

    • Score 2 at 70°
    • Score 6 at 85°
    • Score 10 at 100°–120°
    • Score 6 at 135°
    • Score 2 at 150°
  • Trunk lean20% of this score

    How far your chest leans forward at your lowest point.

    • Score 2 at 5°
    • Score 6 at 15°
    • Score 10 at 30°–45°
    • Score 6 at 60°
    • Score 2 at 70°
  • Lowering time20% of this score

    From your plant foot landing to your lowest point. Faster is better.

    • Score 10 at 0.12 s
    • Score 6 at 0.18 s
    • Score 2 at 0.25 s
  • Hip drop15% of this score

    How far your hips drop, as a share of your standing hip height.

    • Score 2 at 3%
    • Score 6 at 6%
    • Score 10 at 10%–18%
    • Score 6 at 25%
    • Score 2 at 30%
Penultimate step15% of overall

Your second-to-last step: the long, low step that sets up the plant.

  • Length vs. your previous step30% of this score

    Penultimate step length divided by the step before it. Longer is better.

    • Score 2 at 0.8×
    • Score 6 at 1×
    • Score 10 at 1.15×
  • Length vs. your height20% of this score

    Penultimate step length divided by your height.

    • Score 2 at 0.45×
    • Score 6 at 0.65×
    • Score 10 at 0.85×
  • Hips lowering20% of this score

    How far your hips lower during the step, as a share of your standing hip height.

    • Score 2 at 0%
    • Score 6 at 2%
    • Score 10 at 5%–10%
    • Score 6 at 15%
  • Heel-first plant15% of this score

    How your plant foot first touches the ground.

    Heel first: 10. Flat foot: 6. Toe first: 2.

  • Step time15% of this score

    From your previous foot landing to your penultimate foot landing. Quicker is better.

    • Score 10 at 0.2 s
    • Score 6 at 0.28 s
    • Score 2 at 0.4 s
Approach15% of overall

Your footwork and speed on the way in.

  • Footwork pattern25% of this score

    Your step count and which foot you finish on.

    A 3- or 4-step approach that finishes right-left (right-handed) or left-right (left-handed): 10. The right finish with extra or missing steps: 6. A wrong-foot finish: 2.

  • Inefficiency flags25% of this score

    Habits that bleed speed.

    Starts at 10. Minus 5 for a bunny hop, 3 for a stutter step, 3 for a standing start and 2 for a crossover step.

  • Speed build-up20% of this score

    The share of your steps that get faster on the way to the penultimate step.

    • Score 2 at 0%
    • Score 6 at 50%
    • Score 10 at 100%
  • Speed into the plant15% of this scoreSet by level

    How fast you are moving as you plant. Faster is better.

    • Score 2 at 2.5 mph
    • Score 6 at 4.2 mph
    • Score 10 at 5.9 mph
  • Forward drift15% of this score

    How far you float forward in the air. Less is better.

    • Score 10 at 19.7 in
    • Score 6 at 33.5 in
    • Score 2 at 47.2 in

Your overall score is the weighted average of the seven scores, so technique counts for 70% and jump height and reach for 30%. If part of your approach isn't visible in the video, it's skipped and the rest are reweighted. These targets are starting values based on typical ranges in volleyball jump research, and we'll tune them during the beta. Rubric v0.2.

Coming soon

What's next

Training to jump higher

Training built from your scores to help you add height.

Personal analytics log

A log of every session, so you can see your progress over time.

Team tracking and analysis

Track and compare analyses across a whole team.

Pricing

Free while we're in beta

The beta won't last forever, and paid plans will come later.

FAQ

Questions

What do I need?

A phone that records at 60fps, and a friend to hold it or a tripod. Film from 10 to 15 feet to the side of your approach, at head height. No sensors, markers or special clothing.

What do I need to tell it about me?

Your height, hitting hand, level, and men's or women's norms. Standing reach is optional: skip it and it's estimated from your height.

Does the camera angle matter?

Yes, a lot. Film from the side at a right angle to your approach, with the phone held still: from behind or at a slant it can't see your steps or knee bend, and distances come out wrong.

How accurate is it?

It hasn't been checked against measured jumps yet, and we're doing that during the beta, so treat the numbers as estimates and watch how they change between your own clips.

Does it replace a coach?

No. It works alongside a coach, showing what changed from one rep to the next.

Does my video get uploaded anywhere?

No. Everything runs on your phone, and no video leaves it.

If I analyze the same video twice, do I get the same score?

Yes. The same video always gets the same score.

Which jumps does it analyze?

One spike approach per video. Block jumps and back-row attacks are not supported yet.

How does it spot a bunny hop or a stutter step?

It tracks every time each foot touches the floor, and flags a bunny hop when both feet land together after a moment in the air before your penultimate step, along with stutter steps, crossover steps and standing starts.

How much does it cost?

It's free during the beta. The beta won't last forever, and paid plans will come later.

Which phones does it work on?

We plan to release it for both iOS and Android.

When does it launch?

Late fall. Join the waitlist and we'll email you when it's out.

About

Hi, I'm Shane

Shane Racey

I studied operations research at Cornell and pole vaulted for Cornell and Kentucky. Now I work in data science and build small, focused apps.

I recently got into volleyball since retiring from track and field. I noticed that some rec players struggle with the approach and proper jumping. I knew that with my biomechanics and coding background, that I could help more people with this tool.

Questions or feedback? Email me at hello@statjump.app.

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