Post By: Sensei Kris
Push-ups are one of those exercises that we all know we should do, but don't always want to do them. But they're important, and for many reasons besides being a requirement for each of the belt ranks! In the last few years I've learned and discovered a lot about doing these things over and over and over. As recently as three years ago, I still couldn't really do full-length push-ups due to a shoulder injury sustained when I got T-boned by an SUV while riding my bicycle home from the office. But those days are behind me.
Up front, though, let's acknowledge that many of us have learned how to cheat at push-ups, by sticking our rear ends way up in the air or just barely bending our arms at all. And while that might let you keep up with the pace of the class, it's only really cheating one person - you. So the first step in this 12-step program is to admit you have a problem with push-ups and to commit to doing them correctly. Because cheating yourself just means that you will never develop the muscles and coordination to do the technique correctly.
From a physics perspective, there are really two things to look at in the motion of performing a push-up: force and work. So I did a little physics to calculate the way the force you are applying changes at different points during the push-up, and guess what? Just like the cheaters have always known and avoided, the hardest part - the maximum force you have to apply - happens at the start when you're closest to the ground. If you do a full-length push-up, with your back and legs perfectly aligned, and you start as close to the ground as possible, you are lifting about 62.5% of your body weight at the start of the push-up. So if you weigh 120 pounds, you're basically doing a 75 pound bench press. But this force drops off as you extend your arms and change the angle your body makes with the ground. At maximum arm extension, this force is approximately 58% of your body weight, so that 120 pound person is only doing a 70 pound bench press. Not a lot of difference, but over the course of many push-ups, it adds up. I also looked at how the distance between your legs changes the forces. And it turns out that the force does decrease as you spread your legs, but even at a 60-degree angle, you still have about 94% of the maximum force possible.
In terms of work, which is a measure of the amount of energy you use to lift your body against the force of earth's gravity, the results are a little more interesting. Doing a half-push-up uses less than 40% of the energy required to do a full push-up. So if you are only bending your arms half-way, you are really losing out on training. Doing 10 all-the-way-to-the-ground pushups burns as much energy as doing 26 half-pushups! That's a big difference. And spreading your legs actually lets you burn a few more calories, so long as you don't spread them too far (don't put your feet farther apart than your arm span.)
And speaking of calories, if you go to FatBurn.com and use their free tool for calculating calories burned during exercise, you find that a minute of moderately paced push-ups burns about 11 calories for a person my size (basically 0.61 calories per 10 pounds of body weight.) So it's not just about the mechanics, but how fast you do them.
Finally, there are some easy modifications to make to help you work toward your next push-up mile mark. We all know about the modified position, doing push-ups from your knees. But you can do full length in a variety of ways. To make them easier without sacrificing form, change the level of your head slightly by positioning your hands on chairs or a low wall or windowsill. When that gets easy, try doing them from much lower - like the edge of the aiki mat. Then go to where you head and hands are even. On the other hand, if you are finding full length pushups easy, but don't want to just do another 100 of them, try raising your feet higher than your hands. These techniques are easy if you do them outside on the hill - all you need is to reposition your body to make it easier or harder.
Don't forget to always keep your back straight and your rear end down. Work toward being able to do 10 perfect form pushups. Then go for 20. Or pick up the pace. Lately, my routine for pushups is to do a set of 50, rest and stretch my arms for a minute or less, do a set of 40, rest, set of 30, rest, set of 20, rest, and a set of 10 (that's 150 total). When that gets easy, I'll shift to sets of 55, 45, 35, 25, 15, and 5. And then work up. And when I'm close to the next mark, I'll use my hand and foot positions to help me transition to the new goal.
The bottom line is simple. It's up to you to keep yourself honest and to get the most out of every training session. If you are going to train, get the most out of the time you're putting in. We're all too busy to waste time by training at less than 100%.
|Photo By: Ken Smith|