Hips opened late0:14
Power leaks out the back — your hips rotated 0.3s after your hands started.
iOS
Your sports and movement clips,
reviewed closely.
Drop a clip in. Get a coach back.
Why I'm building thisBuild With Gemini XPRIZE- 01Capture
- 02Collect
- 03Review
- 04Analyze
- 05Get tips
TODAY · 4 NEW CLIPSREVIEW · 0.25×ANALYZING · 12%ANALYZING · 47%ANALYZING · 89%REVIEW COMPLETE · 3 FINDINGS
Why I'm building 4thCoach
Inspired by my kids. Pushed by a contest.
A few days before I ran across the Build With Gemini XPRIZE, I'd started a rough concept for my kids. They play soccer, flag football, golf, and baseball — and almost never watched themselves play back. The feedback loop on how they were actually moving stayed open too long, if it ever closed. The contest gave me a reason to push it further.
I've been interested in tech, business, and design for a long time, and thought this might be a chance to push myself on all three at once — while learning to build seriously with AI and finding out what it takes to run a business solo. It's a side gig, squeezed into the hours around work and family time — but progress has been swift. What I need now is to refine the concept into something people find useful. If 4thCoach would be useful to you, the things that actually help are real usage, honest feedback, and telling someone else about it. If you want to see how it works under the hood, the proof page shows the pipeline, the evals, and the open books.
— Bryan Elkus, Michigan, USARace to the deadline
One founder, one shot — here's the tape.
Everything that helps 4thCoach compete in the Build With Gemini XPRIZE — the real numbers, climbing while the submission clock runs down.
See the full proof2days to submission
Clips reviewedUnique viewsTotal usersRevenue
- Clips reviewed
- Unique views
- Total users
- Revenue
Clips reviewed149
Unique views0.1k
Total users29
Subscribers0
Revenue$0
Every number here is read straight from production.
You filmed it.
Now what?
This is the part 4thCoach fixes.
Built for the people behind the camera
If you're already filming, you're already halfway there.
4thCoach is for the people who shoot the clips, not the analysts who get paid to study them. Any sport, any movement. Three groups, one app.
Sports parents
You're already at every game with your phone out. 4thCoach turns those clips into coaching your kid actually wants to see.
- Show your kid what worked, in plain language
- Catch the moments coaches miss in real time
- No "good job, buddy" — actual feedback
Self-directed players
Rec league, weekend lifter, casual golfer, club tennis, the 5K you're chasing. You knew something felt off. 4thCoach tells you what it was.
- A second set of eyes when no coach is watching
- Catch the mechanic you'd never spot yourself
- One drill to try before next session
Youth coaches
You volunteered to coach because nobody else would. 4thCoach gives you sharper, specific notes for Tuesday practice.
- Notes ready before the bus gets back
- One concrete thing per kid, per week
- Looks like you stayed up studying film
Not for:D1 programs, pro scouting departments, anyone with a film room. We're built for phones, not stadiums.
What 4thCoach reviews
24 sports and movements, and counting.
This list isn't marketing copy — it's read from the same catalog the app classifies against. When 4thCoach learns a sport, this page says so on its own.
American Football
AnalyzedBaseball
AnalyzedBase sliding · Catching · Fielding · Hitting · Pitching · Throwing
Basketball
AnalyzedCrossover · Defense · Defensive slide · Dribbling · Footwork · Free throw · Layup · Passing · Rebounding · Shooting
Boxing
Cross · Footwork · Hook · Jab
Cricket
Batting · Bowling
Dancing
AnalyzedDiving
AnalyzedField Hockey
Drag flick · Dribbling · Goalkeeping · Hitting · Push pass · Receiving · Tackling
Hand-tuned coaching on every skill
Flag Football
Ball carrying · Catching · Flag pulling · Route running · Throwing
Hand-tuned coaching on every skill
Golf
AnalyzedBunker · Chip · Drive · Iron · Pitch · Putt
Hand-tuned coaching on every skill
Gymnastics
AnalyzedBackward roll · Bridge · Cartwheel · Forward roll · Handstand · Headstand · Roundoff
Hand-tuned coaching on every skill
Pickleball
AnalyzedDink · Groundstroke · Overhead smash · Return of serve · Serve · Third shot drop · Volley
Hand-tuned coaching on every skill
Running
AnalyzedDistance running · Sprint
Skateboarding
AnalyzedSnowboarding
AnalyzedBalance · Carving · Edge control · Jumps · Speed control · Turning
Soccer
Dribbling · Goalkeeping · Passing · Shooting · Tackling
Hand-tuned coaching on every skill
Softball
Fielding · Hitting · Pitching · Throwing
Surfing
AnalyzedBottom turn · Cutback · Duck dive · Paddling · Stance · Take off · Top turn · Wave reading
Swimming
AnalyzedBackstroke · Breaststroke · Butterfly · Freestyle
Tennis
Backhand · Forehand · Serve · Volley
Hand-tuned coaching on every skill
Track & Field
High jump · Hurdles · Long jump · Shot put · Sprint
Volleyball
AnalyzedPassing · Serve · Set · Spike
Water Skiing
AnalyzedBody position · Edge control · Getting up · Handle pass · Turning · Wake crossing
Weightlifting & Strength
AnalyzedBench press · Clean · Deadlift · Jerk · Overhead press · Pull up · Push up · Row · Snatch · Squat
Hand-tuned coaching on every skill
Analyzed:16 of 24 have already had real clips reviewed in production. The rest are ready and waiting for the first one. Anything outside the list still gets reviewed by the general movement engine — just without the sport-specific measurements.
From clip to coach in minutes.
You already shot the clip. 4thCoach handles the rest.
01 · ADD
Drop in a clip.
Share from Photos, or pick from your library. Vertical, horizontal, slow-mo — 4thCoach handles whatever's already on your phone.
02 · REVIEW
4thCoach reviews.
Every frame. End to end. Body tracked, mechanics measured, findings written. Usually within a couple of minutes.
Hips opened late
0:14
03 · SEE
You see what it saw.
Findings in plain language, pinned to the exact frame they came from. Tailored to your level of play.
Built for the third look, and the tenth.
The first look is for the highlight. The third is where you actually learn something. 4thCoach's player makes the replay quick, precise, and honestly kind of fun — for the kid you're showing, or for you.
Feel every frame as you scrub.
A haptic click on every keyframe. Find the swing, the throw, the strike — with your thumb, not your eyes.
See what a quarter-speed reveals.
Tap a speed to slow to 0.25× — or 0.1×. Pause to step a single frame. The body does things in six frames you can't catch at full speed — that's where the coaching lives.
Scrub anywhere on the screen.
Drag from any pixel of the video — no aiming at a hairline timeline. The whole frame becomes a scrubber, so your thumb stays where your eyes already are.
‹▶›
0:14 / 0:310.25×
TAP · PAUSE · HOLD · SCRUB · SPEED
a real finding · spelled out
Tailored coaching cues
and a breakdown anyone can understand.
Specific. Actionable. Kind in tone. The opposite of a grade.
Your hips opened late.
Coach voice
On the swing at 0:14, your hips started rotating after your hands had already begun moving forward — that sequence usually shows up as a "cast." Try a few slow-motion swings tomorrow: start the rotation from your back foot, let the hips lead, and feel your hands stay back.
What we saw
On the swing at 0:14, your hips started rotating after your hands had already begun moving forward. That sequence usually shows up as a "cast" — power leaks out the back of the swing because the body isn't firing in order.
What to try
A few slow-motion swings tomorrow. Start the rotation from your back foot, let the hips lead, and feel your hands stay back. Three reps before your next at-bat.
4thCoach · reply
The "cast" usually starts with the upper body wanting to help. Two flags to watch: the trail elbow leaves your rib cage before the hips fire, and the bat head starts moving before the belt buckle turns. Fix the sequence and the bat speed shows up on its own.
4thCoach · reply
Think of a whip. The handle moves first, then the tip snaps last. Your hands are the tip — they should be the lastthing to move, not the first. Right now you're throwing the tip before you crack the handle.
This is what every finding looks like — three parts, plain language, pinned to the frame.
ASK 4THCOACH · CHAT WITH YOUR COACH
The coach is a message away.
Question a finding. Dig into a swing. Get another take. Ask 4thCoach is a chat that already knows your clip — and it never makes you feel dumb for asking the simple questions.
Try it in the appExample: a user asks 4thCoach about a finding and gets a coaching reply, then asks to see it on the clip and 4thCoach points to the timestamp.
One clip is a tip. Many clips are a trend.
4thCoach remembers. It rolls up the same issue across every clip the player has added — so you can see it actually getting better, and see the moments that were already clean, not just the ones to fix.
- Ranked by what to drill first.The issue that shows up most, across the most clips, sits at the top of the list.
- Clean moments count too.4thCoach flags the reps your kid already nailed — proof it's landing, not just a pile of corrections.
- Play the moments back-to-back.Every flagged moment for one issue, one after another — or overlay a clean rep ghosted over a flawed one.
Open the app. Here's the day-to-day.
The screens you'll spend actual time on — once you're past the hero shot. No setup, no manual tagging, no folders to organize. Just clips, sorted by what's in them.
2 findings
Every clip, with the findings already counted
Open the library, see every clip you've ever shot — already sorted by sport and length. The coral badge tells you which clips have something worth a closer look. Saturday's at-bat, last week's free kick, the swing you've been working on — all right where they should be.
Pull up the swing, the throw, or just last week
Filter by sport, by position, by your kid's age tier, by whether 4thCoach found something worth showing. Two taps and you're looking at every fastball, every shot on goal, every serve from the season — not scrolling through 800 photos to find the one.
BaseballBatterRight-handedDeveloping
Tagged for you, while you make dinner
4thCoach reads the clip and figures out the sport, the position, the dominant hand, roughly where the player is on the skill curve. You don't type a thing. You never type "baseball" or "soccer" into a search bar to find your kid's at-bat.
You always know what's happening
A live status bar for every clip in the queue — uploading, analyzing, done — so you can hand off a clip and get on with your day instead of babysitting a spinner. Most clips finish within a couple of minutes.
On the swing at 0:14, your hips started rotating after your hands had already begun moving forward — so power leaks out the back of the swing instead of going into the ball.
Too technical? Tap Simpler. Not enough? Tap Deeper.
Every finding is one explanation you can move up and down. Tap Simpler and 4thCoach rewrites it in plainer language — again, and again, until it lands for a nine-year-old. Tap Deeper and it goes the other way, into the mechanics a coach would name. Same moment, same clip, pitched wherever you need it.
Go ahead — the buttons work. This is the real ladder, ends and all.
What's new in 4thCoach
All updates →New Subscription Options for 4thCoach+
We've added new monthly and annual subscription plans for 4thCoach+, giving you more flexibility to choose the best option for your coaching needs. Plus, you'll now see introductory offer prices directly in the paywall.
Launch pricing for 4thCoach+
Start a monthly 4thCoach+ subscription by August 17 and it's $3.99/month for your first six months, instead of $14.99. After that, new monthly subscriptions start at $4.99/month for the first three. You'll see the offer price before you subscribe.
Field Hockey is now a fully supported sport!
Great news, field hockey players! You can now get AI coaching feedback on your field hockey clips. We're excited to help you improve your game.
Things people ask.
What does 4thCoach mean?
A player usually has a coach or two — the one running practice, the one on the sideline, the voice in your own head. 4thCoach comes after all of them, and that's the point of the name. Coaching is a human thing; 4thCoach just brings a closer look and one specific thing worth talking about — with your kid, with your coach, or with yourself. It's meant to make those conversations better, never to replace them.
Is 4thCoach a video editor?
No. We don't help you cut highlights for Instagram. We help you understand the clip — what happened, what to try next.
What does it cost?
4thCoach is free to start — no card, no trial clock. Paid list price is $119.99/yr — $10/mo, about what a single private lesson costs — or $14.99/mo month to month. Every clip 4thCoach reviews costs real money in AI inference and compute. New subscribers usually get an intro offer on the monthly plan — a lower price for the first few months, then list. You'll see the live offer on the subscribe screen in the app. Cancel anytime.
What does the intro offer get me?
A lower monthly price for a set run of months when you first subscribe, then the standard list price. It applies to the monthly plan only — annual is already priced well below twelve months of monthly. The live offer, its length, and any end date show on the subscribe screen in the app; when an offer has an end date it is a real calendar date, not a countdown gimmick.
What happens when my intro price ends?
You roll onto the standard list price, and you'll know the date well before it arrives — nothing changes silently. You can cancel at any point before then and keep access through the end of the period you've already paid for.
If I cancel and come back, do I keep my intro price?
No — intro pricing is for new subscribers, tied to the subscription rather than to your account forever. If you cancel and resubscribe later, you pay whatever is offered then, which may simply be the list price.
Do I need to record clips with 4thCoach?
No. Use your phone's camera the way you already do. 4thCoach works on whatever's already in your library.
What if I don't know what to look for?
That's the whole point. 4thCoach doesn't expect you to know. It reviews the clip, tells you what it found, and explains it in plain language.
Will it work on a clip I shot from the bleachers? In low light?
Vertical and horizontal both work. The brighter the clip and the closer you are to the action, the better the review — but 4thCoach will tell you when a clip is too far or too dark to read confidently.
What sports and movements does 4thCoach understand?
4thCoach understands 24 sports and movements today — American Football, Baseball, Basketball, Boxing, Cricket, Dancing, Diving, Field Hockey, Flag Football, Golf, Gymnastics, Pickleball, Running, Skateboarding, Snowboarding, Soccer, Softball, Surfing, Swimming, Tennis, Track & Field, Volleyball, Water Skiing, and Weightlifting & Strength. Field Hockey, Flag Football, Golf, Gymnastics, Pickleball, Soccer, Tennis, and Weightlifting & Strength get hand-tuned coaching rubrics on every skill; the other 16 run 4thCoach's general movement engine. And it isn't only organized sports — drop in a run, a lift, a jump, or any other movement and 4thCoach still reviews it in plain language, just without the sport-specific measurements. This list is read straight from the live catalog: new sports appear as families ask for them, without an app update.
Will my clips be used to train AI models?
No. Your clips are yours. We don't use them for training, and we don't share them.
How is this different from Photos?
Photos organizes by when. 4thCoach organizes by what happened.
plans
Start free. Upgrade when the free ceiling starts pinching.
Both plans review the same clips with the same coach. Paid raises the ceiling — more clips a day, more players, and your findings kept for good instead of a rolling window.
Free
$0
No card. No trial clock.
- 2 clip analyses a day, for your first 100 clips — then one a week
- 2 players on the account
- Findings from your last 10 clips — your top pattern in full
- Coach chat, narration, and sharing
- Every sport 4thCoach covers
4thCoach+
$119.99/yr
$10/mo, billed yearly · or $14.99/mo · cancel anytime
About one private lesson — for the whole year.
- Everything in Free, plus:
- 10 clip analyses a day
- Up to 6 players on one account
- Findings kept all-time — every pattern, not just the top one
- Trend and wins over time
If you join under an intro offer, that rate holds for its stated months, then rolls onto $14.99/mo.
4thCoach+ plan
There's a teaching moment in every clip.
One paid plan. Free to start, cancel anytime.
$14.99/mo$119.99/yr
$10/mo, billed yearly · or $14.99/mo
DownloadUp to 6 players on one account · 10 analyses/day · Cancel anytime
A year is about what a single private lesson costs — and it covers up to 6 players on one account, 10 clip analyses a day, all season. Every clip 4thCoach reviews costs real money in AI inference, and this is priced to support that while the product takes shape. Subscribing is also the strongest signal I can show the Build With Gemini XPRIZE. Cancel anytime.
Built solo for theBuild With Gemini XPRIZE · iOS