Uploaded February 2026 | Updated September 2026, 1 week ago
Pushing the Boundary Between Control and Failure
In this 2010 chalkboard talk, Greg Glassman explains threshold training as a fundamental but frequently misunderstood driver of human performance. He describes it as a deliberate process of pushing speed, load, or intensity to the point where errors emerge—then learning to regain accuracy and control without backing off. Borrowing from shooting sports and the classic overload principle, Glassman frames threshold training as an essential tension between velocity and precision: improvement only occurs when performance is stressed beyond comfort, forcing physiological adaptation and refined motor control. Whether in athletics, surgery, typing, or sport, the highest levels of skill are not achieved by avoiding mistakes, but by repeatedly testing the limits of speed and force while maintaining a normative standard of accuracy. Over time, this process produces stronger tissues, better coordination, and the capacity to operate safely and effectively at higher power outputs.
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The Glassman Archive is a comprehensive repository of Greg Glassman’s work during his leadership of CrossFit.
This collection preserves his original material and the foundational ideas he shared. We believe these insights are worth promoting and protecting. These lessons continue to inform his ongoing work with the Broken Science Initiative and MetFix.
Pushing the Boundary Between Control and Failure
In this 2010 chalkboard talk, Greg Glassman explains threshold training as a fundamental but frequently misunderstood driver of human performance. He describes it as a deliberate process of pushing speed, load, or intensity to the point where errors emerge—then learning to regain accuracy and control without backing off. Borrowing from shooting sports and the classic overload principle, Glassman frames threshold training as an essential tension between velocity and precision: improvement only occurs when performance is stressed beyond comfort, forcing physiological adaptation and refined motor control. Whether in athletics, surgery, typing, or sport, the highest levels of skill are not achieved by avoiding mistakes, but by repeatedly testing the limits of speed and force while maintaining a normative standard of accuracy. Over time, this process produces stronger tissues, better coordination, and the capacity to operate safely and effectively at higher power outputs.
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The Glassman Archive is a comprehensive repository of Greg Glassman’s work during his leadership of CrossFit.
This collection preserves his original material and the foundational ideas he shared. We believe these insights are worth promoting and protecting. These lessons continue to inform his ongoing work with the Broken Science Initiative and MetFix.
