More about muscles

I am following up on my post about pushups, which made at least two readers say "huh???" Let's see if I can be a little clearer this time around.

You already know that you can accomplish very similar actions using different combinations of muscles. Maybe you've taken voice lessons, and learned that inhalation is much more complicated than you ever suspected. If you use your diaphragm, you can inhale a larger volume of air with less neck tension. This is great for vocal quality and long-term vocal health. But lots of us have to practice for a long time if we want to move our diaphragms and keep our shoulders still when we inhale.

One of the reasons that training programs for runners include recovery runs is that we use our muscles in different ways on different days, even if we're completing the same action. When you run on fatigued legs, you engage different groups of muscle fibers. This process of learning to recruit a wider array of muscle fibers makes you a stronger, more fatigue-resistant runner over time.

When you do a pushup, you can engage different muscles to different extents. You can't do a pushup with zero trunk engagement; you can't do a pushup with zero arm engagement. But your pecs can do more or less of the work, depending on the signals they get from your brain. I don't have EMG results to show that I'm getting more pec activation when I think deliberately about using my pecs, but I know I can do a whole lot more reps with a whole lot less effort when I consciously call on the patterns of movement I learned while bench-pressing.

The next time you're sitting at a desk, try this: hold your arms close to your body, and push yourself away from the desk. Next, imagine that you are a smuggler, and you have a valuable golden orb tucked into each armpit. Squeeze your chest and your arms together tightly so that your hidden cargo doesn't go crashing to the floor, and hold that position while you push yourself away from the desk again. For me, there's a huge difference in the amount of oomph I can generate. Option A is mostly arms, option B is mostly pecs, and pecs exist precisely so you can push heavy things effectively.

Tell me if that makes more sense, please.