Critical Force
Giles et al. · 2019, 2021
The maximum force your fingers can sustain on a hold without progressive fatigue. Knowing this threshold turns climbing endurance training from guesswork into prescription.
Giles et al. · 2019, 2021
The maximum force your fingers can sustain on a hold without progressive fatigue. Knowing this threshold turns climbing endurance training from guesswork into prescription.
Zourdos et al. · 2016
A 10-point scale that measures how many reps you had left in the tank. Programs that use RIR autoregulate load week to week — no fixed percentages, no missed gains from bad days.
Schoenfeld et al. · 2017
Moderate loads (6–12 reps) build the same muscle as heavy loads when total volume is matched. Protora prescribes by volume, not myth — so your gains aren’t held hostage to "the right rep range".
Monod & Scherrer · 1965
The original physiological framework that defines the boundary between sustainable and unsustainable effort. Every endurance threshold concept — including Critical Force — extends from this 60-year-old foundation.
Seven disciplines, each with its own scientific literature, its own zone system, its own periodization model.
Critical Force. Hangboard periodization. CNS fatigue tracking.
Explore toolsLever torque analysis. Planche biomechanics. Progressive overload.
Explore toolsRPE autoregulation. DUP cycles. Nervous system load.
Explore toolsMEV/MAV/MRV. Myofibrillar hypertrophy. Volume landmarks.
Explore toolsMetCon pacing. Energy systems. Recovery ratios.
Explore toolsAerobic / anaerobic split. Heart rate zones. Sparring load.
Explore toolsSleep debt. Nervous system status. Readiness scoring.
Explore toolsEvery calculator cites its paper. Every zone threshold has a name behind it. When we can’t cite, we don’t claim.
Forget "today’s calories." Protora asks how your Critical Force is trending this quarter, whether you’re plateauing, and what your cross-discipline load looks like.
Your training data never leaves Firebase. Export to coach means you send the file — we don’t transmit on your behalf. Algorithms run server-side so your numbers stay yours.
Free isn’t a trap. Pro isn’t locked down. Elite is research-grade. Pick what fits, upgrade when you need more.
| Feature | Free Forever Free DOWNLOAD | RECOMMENDED Pro $3.99 mo · $29.99 yr SAVE 37% DOWNLOAD | Elite $7.99 mo · $69.99 yr SAVE 27% DOWNLOAD |
|---|---|---|---|
| PROTOCOLS | |||
| 7 disciplines + 27 protocols | ✓ | ✓ | ✓ |
| Scientific references | ✓ | ✓ | ✓ |
| TRACKING | |||
| Quick workout logging | ✓ | ✓ | ✓ |
| Active plans | 1 | Unlimited | Unlimited |
| RPE / RIR entry | ✓ | ✓ | ✓ |
| Custom workout builder | — | ✓ | ✓ |
| PROGRAMMING | |||
| RPE autoregulation | — | ✓ | ✓ |
| DUP cycle planner | — | ✓ | ✓ |
| Plateau alerts | — | ✓ | ✓ |
| Periodization planner | — | ✓ | ✓ |
| DISCIPLINE-SPECIFIC | |||
| Critical Force progression | — | ✓ | ✓ |
| Volume landmarks (MEV/MAV/MRV) | — | ✓ | ✓ |
| Lever progression Lv 4+ | — | ✓ | ✓ |
| ANALYTICS | |||
| Career stats + heatmap | ✓ | ✓ | ✓ |
| Volume per muscle group | — | ✓ | ✓ |
| Training stress score | — | ✓ | ✓ |
| NUTRITION | |||
| Macro tracking | ✓ | ✓ | ✓ |
| BMR / TDEE calculator | ✓ | ✓ | ✓ |
| Smart macro periodization | — | ✓ | ✓ |
| EXPORT & TOOLS | |||
| Export to coach (PDF/CSV) | — | — | ✓ |
| Custom periodization templates | — | — | ✓ |
Free tier is live on the App Store. Pro and Elite subscriptions activate in-app shortly after install.