Big propulsion, faster laps. The deltoids are the true MVPs of the pool.

They’re the first to engage at the catch and the last to quit on the finish. While the core keeps the swimmer’s level, the deltoids are doing the heavy lifting, rotating the arms, stabilizing the shoulders, and turning every ounce of effort into pure forward momentum. If the swimmer is looking to shave seconds off their PB, it’s time to give the “boulder shoulders” the credit they deserve.