The Gym Prepares You to Throw. It Doesn't Replace Throwing.
Many baseball players spend the off-season getting stronger in the gym, hoping it will improve their throwing performance and prepare their arm for baseball season. But when the first few throwing sessions arrive, it’s common for their arm to feel sore, heavy, or just not ready at the start. It’s easy to wonder, “I’ve been training all winter - why doesn’t my arm feel ready?” The answer is simple: the gym prepares you to throw, but it doesn’t replace throwing.
Why Strength Isn’t Enough
Don’t get me wrong, the gym is fantastic when it comes to training for baseball players. The gym builds muscular strength and power, muscle mass, and even improves the strength of tendons and bones. These adaptations raise your physical capacity and prepare your body to better tolerate the demands of baseball. Overall, this increases your ability to produce force and perform.
But throwing isn’t just about strength - its a skill with physical demands that can only be developed by throwing.
Why Throwing Is Different
Throwing a baseball is a very unique and specific skill. It involves the fastest rotational speeds in sport and enormous eccentric forces as the body rapidly decelerates the arm after ball release. This involves not just strength, but efficient mechanics with proper timing, coordination, and sequencing of the entire body. No gym exercise reproduces all of those simultaneously. I love using medicine ball throws, explosive movements, plyometrics, and heavy eccentrics as part of my rehab programming for baseball players. These exercises help bridge the gap because they expose the body to high forces and fast movements. But they still don’t reproduce the unique demands of throwing.
No exercise recreates throwing as well as throwing itself. Think of the gym and throwing as two separate forms of training. The gym develops the physical qualities that support throwing, while throwing develops the specific movement patterns and tissue adaptations required to throw. They’re complementary, but neither replaces the other.
Our bodies adapt specifically to the stresses we place on them. If we squat regularly, our lower body will certainly get stronger, but we’ll also get really good and efficient at squatting. If you train for 100m sprints, you’re going to get really good at short-distance sprinting, but this won’t translate to being able to run a marathon. So when you throw consistently, your arm gradually adapts to tolerate the unique speeds and forces experienced with throwing. These adaptations cannot be fully developed any other way.
This is the reason players often feel sore when they first begin throwing after an off-season despite working out in the gym. You may be physically stronger coming into the season, but your arm hasn’t experienced the unique forces of throwing for months. Even players who continue throwing during the off-season often see a rapid increase in throwing volume and intensity once preseason begins. Your arm simply needs time to adapt to the demands of throwing.
The Gym and Throwing Work Together
By all means, continue to work out in the gym. Lift heavy weights, build strength, build power, and incorporate your lower body and core to really get the most out of your throwing. But don’t expect the gym to completely prepare your arm for game demands. A gradual throwing progression is what teaches your arm to tolerate the unique demands of throwing.
The gym builds the qualities that support throwing. Throwing builds the specific adaptations required to throw.
