In chapter 2 of The Mental Game of Poker, Jared Tendler introduces the Inchworm model to explain how real, lasting improvement in both poker skill and mindset actually happens over time.
The Range of Your Game
Tendler starts by pointing out that every player has a range of performance. Some decisions are made at your peak level, while others come from your worst level. If you could graph every decision you made, it would form a bell-shaped curve, with great play on one end and poor play on the other. This range never disappears, because poker is complex, competitive, and always changing.
Why Perfection Is a Myth
Even elite players don’t play perfectly all the time. There will always be ups and downs in decision quality. Learning increases both your best possible play and exposes where your weaknesses are. Accepting this range is crucial, because fighting it only creates frustration and unrealistic expectations.
The Inchworm Movement
The inchworm idea explains how improvement works across that range. When you learn something new, the front end of your game—your best play—gets better first. That stretches the range wider, because your weaknesses haven’t moved yet. To keep progressing, you then have to improve the back end by fixing the biggest mistakes. When your worst play improves, the whole range shifts forward, making room for the next breakthrough.
In simple terms, progress alternates between raising your ceiling and lifting your floor.
Why Fixing Weaknesses Matters Most
Tendler emphasizes that many players only chase new ideas and strategies. This makes their best sessions impressive, but their bad sessions terrible. Their range gets wider, and when they are tired, tilted, or distracted, they fall apart. Real consistency comes from training weaknesses until they become automatic and no longer collapse under pressure.
Mental Game and Inchworm
The same logic applies to emotions and tilt. Big emotional reactions usually protect your weakest areas. When you eliminate those weak spots, the emotions lose much of their power. As more of your responses become automatic and stable, you gain mental space to keep improving.
How to Measure Real Progress
A key practical lesson is how to judge improvement. Tendler says you shouldn’t compare your worst days to your best days. That will always feel discouraging. Instead, compare your current worst to your previous worst. If your bad sessions are less destructive, shorter, or easier to recover from, then you have improved—even if it doesn’t feel that way.
The Core Message
The Inchworm model shows that sustainable growth comes from a cycle: push your best forward, then clean up your worst. By steadily raising the bottom of your game, you become more consistent, more confident, and better equipped to reach new peaks in both poker and the mental game.