I Spent $40,000 To Prove Them Wrong... Including Me

About this video

• Video Title: I Spent $40,000 To Prove Them Wrong... Including Me
• Channel: Jeremy Ethier
• Speakers: Jeremy Ethier
• Duration: 18:46

Overview

This video details a year-long, $40,000 study conducted by Jeremy Ethier to investigate the efficacy of training muscles in a stretched position versus a contracted position. The study aimed to challenge the prevailing fitness community trend of emphasizing the stretch for muscle growth, exploring whether this focus is overblown. The findings revealed that for most muscles tested, there was no significant difference in growth between stretch-focused and squeeze-focused training, provided a full range of motion was used. However, some specific muscles may still benefit more from a greater stretch.

Key takeaways

• The "Stretch Hype": The fitness community has become obsessed with exercises that maximize muscle stretch, believing it to be the key to S-tier growth.
• Historical Context: Research on the benefits of stretching for muscle growth dates back to the 1970s, with early studies showing significant gains in chickens' lats and humans' calves and chests with loaded stretching.
• Study Design: A comprehensive, year-long study was conducted with 20 subjects using a within-subjects design (comparing stretch vs. squeeze training on opposite sides of the body) and MRI technology for precise muscle growth measurement.
• Challenging Existing Research: Previous studies often focused on biceps, quads, or calves, used less precise measurement methods like ultrasound, or compared exercises with confounding variables.
• Study Findings: Contrary to popular belief, the study found no significant difference in muscle growth between stretch-focused and squeeze-focused training for the chest, glutes, side delts, and rear delts, as long as a full range of motion was used.
• Nuance in "Stretch": The concept of "stretch training" is broken down into three ideas: the degree of stretch (some muscles are built to stretch more), basic range of motion (full ROM is important), and the resistance profile (making the stretch phase harder). The study found the resistance profile in the stretch phase did not significantly impact growth compared to the squeeze phase.
• Exceptions: Certain "biarticular" muscles (hamstrings, quads, calves, triceps) may still benefit more from training in a stretched position due to their ability to cross two joints. The study suggests exercises that maximize stretch for these muscles are beneficial.
• Practical Implications: The findings suggest flexibility in exercise selection. As long as training is hard, volume is sufficient, and range of motion is full, various exercises can be effective for muscle growth. This is beneficial for those working around injuries or with limited equipment.
• Future Research: The study is ongoing, with plans for further research, including an MRI study on back growth comparing rows and pull-downs, to continue refining our understanding of muscle hypertrophy.