On the field, having too much mass in the front of your body can restrict your range of motion when you throw the ball. When it comes to hitting, the swing is very mechanical. You want to be flexible in front of your shoulders and chest so nothing gets in the way of executing those mechanics well. Edgar Martinez once told me that he does work his chest, but in minimal amounts. He’s a guy who puts on mass easily, but he felt that being too bulky in his pecs took away from his swing. He did explosive exercises instead of chest work. We also did a lot of balancing movements that don’t add mass but that maintain strength.
— Allen Wirtala, head strength and conditioning coach for the Seattle Mariners, has trained many elite athletes, including Edgar Martinez, Ichiro Suzuki and Jamie Moyer.