In this 2010 discussion, Greg Glassman defines core strength as the ability to prevent the midline—essentially the spine—from deflecting under load during heavy, functional movement, arguing that true strength is best developed and measured through foundational movements like the air squat, deadlift, and overhead squat rather than isolated core exercises. These functional lifts place increasing demands on midline stability as load or leverage increases, making improvements in performance a direct indicator of improved core strength and overall movement capacity.
This video, by BSI’s co-founder, was originally published in The CrossFit Journal. While Greg Glassman no longer owns CrossFit Inc., his writings and ideas revolutionized the world of fitness, and are reproduced here.
Coach Glassman named his training methodology ‘CrossFit,’ which became a trademarked term owned by CrossFit Inc. In order to preserve his writings in their original form, references to ‘CrossFit’ remain in this video.
Greg Glassman founded CrossFit, a fitness revolution. Under Glassman’s leadership there were around 4 million CrossFitters, 300,000 CrossFit coaches and 15,000 physical locations, known as affiliates, where his prescribed methodology: constantly varied functional movements executed at high intensity, were practiced daily. CrossFit became known as the solution to the world’s greatest problem, chronic illness.
In 2002, he became the first person in exercise physiology to apply a scientific definition to the word fitness. As the son of an aerospace engineer, Glassman learned the principles of science at a young age. Through observations, experimentation, testing, and retesting, Glassman created a program that brought unprecedented results to his clients. He shared his methodology with the world through The CrossFit Journal and in-person seminars. Harvard Business School proclaimed that CrossFit was the world’s fastest growing business.
The business, which challenged conventional business models and financially upset the health and wellness industry, brought plenty of negative attention to Glassman and CrossFit. The company’s low carbohydrate nutrition prescription threatened the sugar industry and led to a series of lawsuits after a peer-reviewed journal falsified data claiming Glassman’s methodology caused injuries. A federal judge called it the biggest case of scientific misconduct and fraud she’d seen in all her years on the bench. After this experience Glassman developed a deep interest in the corruption of modern science for private interests. He launched CrossFit Health which mobilized 20,000 doctors who knew from their experiences with CrossFit that Glassman’s methodology prevented and cured chronic diseases. Glassman networked the doctors, exposed them to researchers in a variety of fields and encouraged them to work together and further support efforts to expose the problems in medicine and work together on preventative measures.
In 2020, Greg sold CrossFit and focused his attention on the broader issues in modern science. He’d learned from his experience in fitness that areas of study without definitions, without ways of measuring and replicating results are ripe for corruption and manipulation.
The Broken Science Initiative, aims to expose and equip anyone interested with the tools to protect themself from the ills of modern medicine and broken science at-large.
Support the Broken Science Initiative.
Subscribe today →
recent posts
Journal Club: February 5, 2026
When number-chasing replaces treating the root cause
The iceberg beneath “normal” blood sugar numbers
