Boulder Blitz runs your training-board sessions for you: it keeps the clock, tells you which climb to try, and keeps score — round after round — so you can stay on the wall instead of checking a phone.
It runs Solo Mode — a structured interval timer for training alone, climb time and rest time on repeat — and Duel Mode, a head-to-head game where two climbers alternate attempts on the same randomly-picked problem. Boulder Blitz also picks the climb for you and lights it up on the board automatically over Bluetooth.
Initial target board: Tension Board.
Want early access, or have an idea for a mode, board, or scoring tweak? Send it over — this opens your mail app with the message ready to go.
The 4x4 is one of the most common structured workouts climbers use to build power endurance — the ability to keep pulling hard moves after your muscles are already fatigued, rather than pure one-move strength or all-day stamina.
Pick four boulder problems around or just below your flash grade — steep, powerful, without good rest positions. Climb all four back to back with little or no rest between them (that's one "4"). Rest around four minutes, then repeat the full circuit three more times (the other "4"). Sixteen problems total, done in four fatigued bursts.
Sustained near-maximal climbing burns through short-term energy stores fast and produces lactate faster than your body can clear it, which is what makes forearms and shoulders "pump out." Repeating that stress with only partial recovery trains the same adaptations sport scientists target in anaerobic interval work: your muscles get better at buffering and clearing lactate, and at keeping recruiting fibers even as the burn sets in. The result isn't more raw power — it's holding onto more of your power for longer once you're already tired, which is exactly the wall you hit deep into a boulder problem or a redpoint crux sequence.
They train different systems, and most training plans use both rather than picking one:
4x4s show up across the sport, from gym rats to World Cup competitors — usually 1–2 sessions a week alongside strength and technique work, not as the whole plan.
The core protocol scales down fine for club and gym climbers — the elite variants (weight vests, near-zero rest) are what to grow into, not start with.
Boulder Blitz's three preset modes aren't arbitrary speeds — they're built around this exact progression, and each one sets both your climb time and your rest time together (mode speed × climbs per round). Set Rapid to four climbs per round and you get four minutes of climbing paired with four minutes of rest: the classic 4x4, at its original proportions. That's the right place to start — it teaches you the pattern before you try to push it.
Once four-minute rest windows start to feel generous, move to Blitz. It halves both sides of the clock — two minutes climbing, two minutes resting, over the same four fatigued bursts — which is a noticeably tighter version of the same workout for climbers who've built some resilience to the format.
Bullet compresses things further still, down to 15 seconds a climb, and at that point it stops being a pure power-endurance drill: there's no time left to work a sequence, so it rewards climbers training decisiveness and speed of movement as much as pump tolerance. Whichever mode you pick, Boulder Blitz keeps the clock and the round count so you can stay on the wall instead of watching a phone.
Grouped block patterns (four fatigued climb/rest rounds, then a longer reset before the next block) are the kind of custom interval pattern on our roadmap — see the request form on the Home tab if that's a mode you'd want.
Boulder Blitz ("the app") is a timer and scoring app for Tension Board climbers. This policy explains what data the app collects, why, and how it's handled.
Tension account credentials. To pick climbs from your board's catalogue and light them up over Bluetooth, the app needs to link your existing Tension Board account. When you do this, your Tension username and password are sent once, over an encrypted connection, to our backend. They are encrypted at rest and used only to obtain and refresh a session with Tension's own service on your behalf — we don't use them for anything else, and we never see or store your Tension password in plain text.
Session data. When you complete a climbing session, the app saves it to your account so it shows up in your session history: board name, target grade and angle, round count and timing, and per-round results (which climb, how many attempts, points scored). This lets you review past sessions across devices.
Bluetooth data. The app connects directly to your Tension Board over Bluetooth to read hold positions and set LED colors for the selected climb. This connection is local, phone-to-board — no Bluetooth or board-identifying data is sent to our servers.
What we don't collect. Boulder Blitz has no analytics SDK, no crash reporting, no advertising, and doesn't request access to your camera, contacts, location, or microphone. Duel Mode player names you enter for a head-to-head session stay on your device only — they are never sent to our servers.
We don't sell or share your data with third parties. Your credentials are used solely to communicate with Tension/Aurora's own service on your behalf, as part of linking your board account.
Your linked account, credentials, and session history are retained until you delete them.
In the app. Open the Profile tab and tap Delete my account. This immediately and permanently deletes your linked Tension account credentials and your full session history from our servers — there's no waiting period, and it can't be undone.
Without the app. If you no longer have the app installed, email us at the address below requesting deletion and we'll confirm once it's done.
Boulder Blitz is not directed at children under 13, and we do not knowingly collect data from children under 13.
If this policy changes, we'll update the effective date above.