Claims

Modern life creates predictable side-to-side mobility loss because people move primarily in forward and backward directions (walking forward, sitting facing forward, training in straight lines), causing bodies to lose the lateral mobility they were designed for.

Tight hamstrings are usually not primarily a flexibility problem but rather a strength deficiency; they lack the ability to control deep ranges of motion, making passive stretching ineffective for long-term relief because without strength development in the lengthened position, the stiffness returns.

Modern sedentary life causes the hips to be one of the first areas to lose mobility because people spend prolonged time sitting.

Most people assume stiff shoulders require more stretching, but the real issue is that modern life requires arms to be in front of the body far more than overhead, causing shoulders to lose full range of motion through disuse in overhead positions.

Because most people spend at least 8 hours sitting daily, the front of the hips can become incredibly stiff, and passive hip flexor stretching alone is usually only half the solution because hip flexors, like hamstrings, need strength through lengthened positions.