Personal Trainer #1: "I see you here all the time, and you always look like you're having a great time, jammin' to the music, it's fun to see, makes you feel good!"
Personal Trainer #2, a few days later: "I just wanted to say: I'm so glad to see you doing that, dancing like that, because I do it too! There was this one time I was on rollerblades and I loved the song that came up so much that I just started doing.. you know..." twists her fingers. "Twirls, and I didn't even realize it until someone in a passing car honked at me and then I got so embarrassed! You forget that other people are out there!"
Apparently, the jaguar-dance/skip/bounce on the treadmill has been noticed. And while the trainers are right that I do it for pleasure... I'm also advancing the music to get to those high-energy songs on purpose, and it's not to dance. It's to save my muscles and joints.
I'm not kidding. Observe, three-second graphics! That orange ball is your center of gravity.
Running for efficiency for me is a very specific body form (see left). It means you hold yourself loose and upright and keep the center of your gravity very close to the center of your hips. You pick up your feet as little as possible, keep your elbows close to your sides—no exuberant swinging—and try to minimize all extraneous movement up, down or side to side. The point of that isn't to run fast... it's to conserve energy so you can run long.
If I move like this (and it requires concentration to do so), I can jog a long time without stopping to rest. And that's great except for one small problem: half the time when I'm running, what gives out first isn't my aerobic capacity... it's my muscles. My heart will be cheerfully keeping time, shouting, "THIS IS GREAT! WE COULD GO ANOTHER MILE!" but the muscles in my thighs and calves are seized up, screaming, "IF YOU PUT YOUR FOOT DOWN ONE MORE TIME I AM GOING TO GO OUT AND YOU WON'T BE WALKING FOR A MONTH!"
And I can't do that. Not just because it's obviously a bad thing to be injured, but because the more my muscles limit my work-out, the less I'll be able to push myself and increase my body's capacity.
My unexpected discovery was that dancing, skipping, jumping or weaving shifts the work from the efficiency-running set of muscles to a completely different set, letting me stretch and rest the first group while maintaining the intensity of the work-out.
When you dance, skip or even just walk jauntily (see left), you swing your hips and the center of your gravity starts shifting from one side of your body to the other (sometimes forward toward your belly and back to your back, if you're exceptionally good at shimmying). Doing that hits more of the muscles along the sides of your legs, stretches/crunches your abs and diaphragm, and gives your calves a rest, particularly if (like me) you dance landing on the balls of your feet instead of the heel.
Additionally, a good hip-swing forces your shoulders to compensate, which means the stretch goes all the way up your body. Running for efficiency means keeping the body in a small, highly defined box; dancing usually involves wide movements of your arms and body, which limbers and loosens them, and engages more muscle groups synergistically. It's like the difference (for me) between doing free weights and using a machine; the machine is very specific in its target, working and exhausting a specific muscle or muscle group quickly, while the free weights are engaging a lot more muscles at the cost of doing so less efficiently.
I find the only way I've been able to keep going with the daily run is by constantly shifting my activity type to alternately stretch, rest or contract different muscle groups. Another good way to do that I got accidentally from stahlhelm... setting a really high incline will force a great calf stretch if you walk up it. So once I'm up on the treadmill, I'm doing any one of three or four things to make it possible for me to target my actual goal—increasing my aerobic capacity—and then I'll work my heart until my muscles start complaining again.
I have never. Ever. Put the knowledge I got out of massage therapy to such aggressive use in my life. It's an intensely mental exercise; I see other people on the treadmills around me simultaneously watching TV, ignoring a book and checking their cellphones while listening to music and I have no idea how they can do that. It takes every neuron in my head to shepherd my body from minute 0 to minute 30 successfully. It's incredibly hard mental work, but it means that when I step off the treadmill, I'm okay; not sore, not limping, not injured, and able to do it again the next day without a problem.
It makes me think of gamers who make spreadsheets just to maximize their characters' performance. I'm doing the same thing, but with my real body.
Anyway. A month and a half ago, I could run 2 minutes consecutively and it took me 22 minutes to run a mile. Now I can run 23 minutes consecutively and I've got my mile time down to 14:20. Getting there...!
(I'd also like to stress: my education gives me a leg up on working these things out, but you don't have to have fancy book-learning to do it; you just have to listen to your body and notice where you're getting sore when you're doing which activities. It can be done!)