TTM isn't built on intuition or templates. Every training decision - load, intensity, timing, adaptation - comes from a model with four decades of peer-reviewed research behind it.
Each pillar is grounded in validated exercise science, published across 40+ years of studies on endurance, altitude, and training adaptation. Click any pillar to explore the science behind it.
In 1975, Banister et al. published a mathematical model describing how training stress produces both beneficial fitness and temporary fatigue simultaneously. This isn't intuition - it's a validated framework published in the Journal of Applied Physiology and applied across 40+ years of endurance research.
The two curves:
Training Stress Balance (TSB) = CTL − ATL. This single number tells you whether you're building or recovering. Performance peaks when TSB sits between +5 and +20 - enough fitness accumulated, but not completely tired.
TTM measures every session's Training Stress Score (TSS) from your Strava data, updates your CTL and ATL daily, and calculates TSB to decide whether the next week should push hard or recover. No guessing. No feeling-based adjustments that miss the physiological reality.
VO₂max - the maximum amount of oxygen your body can utilize per minute - is the ceiling for altitude performance. Above 1,500m, VO₂ partial pressure drops exponentially. A climber with 60 ml/kg/min at sea level operates at approximately 43 ml/kg/min at 5,000m - a 28% reduction in aerobic capacity.
This isn't because you're less fit. It's physics. Oxygen becomes scarce, and your cardiovascular system can only deliver so much. Training hard at sea level doesn't change that O₂ isn't there. But training your cardiovascular system - building your aerobic threshold, stroke volume, mitochondrial density - means you use what's available more efficiently.
O₂ availability follows exponential decay: roughly exp(−alt/8500) × 100% of sea-level oxygen availability. The model calculates this for your summit altitude and adjusts your required Chronic Training Load (CTL) accordingly. Mont Blanc at 4,808m demands significantly more cardiovascular fitness than Toubkal at 4,167m - and Mt Kenya at 4,985m demands more still.
This is why TTM asks for your summit altitude first. Every training decision after that flows from a precise understanding of what your cardiovascular system needs to do. Direct VO₂max testing requires a lab. TTM uses Chronic Training Load (CTL) as its validated field proxy - accumulated systematically over 42 days, CTL reflects the cardiovascular adaptations (stroke volume, capillarisation, oxygen extraction) that determine how well you perform when O₂ is scarce. Pillar 1 is the model. This is why it matters.
The SRS is TTM's proprietary composite measure of cardiovascular altitude readiness, expressed as a 0-100 score. It's not a prediction of summit success - that depends on technical skill, luck, and conditions. It's a measure of whether your aerobic system is ready for the cardiovascular demand of your objective.
SRS components (5 weighted pillars):
Targets: SRS 75+ means you're ready to go. 85+ is exceptional. Below 75, your cardiovascular system isn't yet ready - more training is needed.
Important caveat: SRS is cardiovascular readiness only. Technical skill, proper acclimatisation strategy, and objective hazard assessment are outside the model and equally critical.
The Prescription Engine doesn't hand you a fixed plan and wish you luck. It rebuilds your remaining training block every week based on actual Strava data - what you actually accomplished, not what was scheduled.
The 3:1 structure: Three progressive build weeks followed by one recovery week. This structure is grounded in classic periodization theory (Bompa & Haff, Periodization: Theory and Methodology of Training, 2009) and is widely validated across endurance research - cited in Issurin (2010) and broadly applied in high-performance coaching. Each build block increases Training Stress Score (TSS) by approximately 8-12% relative to the previous block, allowing your body to adapt without plateauing or breaking down.
Other approaches exist - including higher-frequency structures like 6 days on / 1 day off. TTM uses 3:1 because the recovery week is not lost time: it is where adaptation occurs. Volume without structured recovery produces fatigue accumulation, not fitness. The Banister model captures this directly - Chronic Training Load (CTL) grows through the interaction of stress and recovery, not just stress alone.
Taper calculation: The model determines when your taper should begin by solving for the optimal peak timing. This typically represents 10% of your total training block and is calculated to bring your Training Stress Balance (TSB) into the +10 to +15 range exactly at your summit date - the sweet spot where fitness is high and fatigue is cleared.
Weekly recalculation: Every Monday, the Engine reads your Strava history, calculates what you actually achieved, and regenerates the full remaining plan. Missed a session? The Engine distributes that load across remaining weeks. Crushed expectations? Your taper moves earlier or extends. No manual adjustments. No missed window.
In 1956, Hans Selye described the General Adaptation Syndrome - the body's universal response to stress. It has three stages: Alarm (the body is stressed beyond its current capacity), Resistance (recovery begins, the body rebuilds), and Adaptation (it rebuilds stronger than before to handle the same stress more easily next time).
In training, this is called supercompensation. Apply training stress → fitness temporarily drops as fatigue accumulates → recovery occurs → the body adapts to a new, higher baseline. Repeat the cycle at slightly higher load and the baseline rises again. This is how capability is built: not in a straight line, but through repeated stress-recovery cycles stacking upward over months.
Why this can't be rushed: Each adaptation cycle requires 10-21 days. The CTL time constant of 42 days in the Banister model directly captures this biology - it takes roughly six weeks for the body to meaningfully shift its aerobic baseline. Compressing 24 weeks into 8 doesn't accelerate adaptation; it overloads the system before it has time to respond. The result is injury or burnout, not fitness.
What this means in practice: The first 4-6 weeks of a structured program feel hard precisely because adaptation hasn't happened yet. Sessions that feel impossible in week two feel moderate in week eight. By week sixteen, those same sessions are recovery work. That progression is the science working. It cannot be shortcut - only respected.
This is also why TTM's AI coach doesn't prescribe peak load from day one. It reads your current CTL (where your body actually is today), tracks your daily Strava data to see how quickly you're absorbing load, and increases stress only when the data shows you've adapted to the previous level. The program isn't built around what you should be able to do - it's built around what your physiology shows it can currently handle.
TTM's model measures cardiovascular altitude readiness with precision. The research is sound. The math is validated. But we're explicit about scope:
A high SRS means your cardiovascular system is ready. It doesn't mean you'll summit. That also requires technical skill, proper acclimatisation strategy, good fortune with weather, and the experience to know when to turn around. Every climber should use this as one part of their preparation - not the whole story.
Explore the algorithm with real-world scenarios and see how TTM builds a training plan tailored to your altitude objective.