Over the last few years, getting physical—tennis, weightlifting, massage, acupuncture—has been the main way I’ve kept my life worth living. Of these bodywork practices, tennis has been the most important to me. It’s the way I get out of my head, discharge stress, feel my anger, transpose it from my psyche into a little yellow ball that I then get to smack as hard as I can.

I love my friends whom I play tennis with, but on the court I love beating them. I relish in watching the ball skim a few inches above the net and land a few inches from the baseline and just enough to either side of their bodies that they can’t reach it. This doesn’t happen every point, of course—my friends often beat me, and I often miss even easy shots—but when it does, it’s like an orgasm: this fantastic release of pent-up energy, all my frustration at the world expelled from arm to racket to ball and into the ground near my opponent’s feet.

I am a cloud, and there is a charge built up inside me, and when I hit a good shot, that’s lightning.

Well, last week, as I reached for a forehand, I plopped my right foot down, felt a “pop” in my calf, and could no longer move. My friend/opponent helped me hobble to the car. I’ve been hobbling ever since.

For the first two days I thought: this will be annoying, but not that bad. Like having a cold; a brief period of being stuck mostly in the house. But, really, it has been bad. I’ve felt unexpectedly emotionally affected by my setback. I know it’s just been a week, and I know I’m being a baby, but without the ability to partake in my usual physical modes of emotional release, I’ve begun to feel pent-up. If I am a cloud, then I am becoming one with too much charge. I need a discharge.

Or, to use another metaphor: think of yourself as a cup. At the bottom, you are filled with the energy of the inherent stressfulness of life—conflicts with family and friends, your job, that annoying guy who cut you off in traffic. Atop that, add in your traumas—the things that keep you up at night, the things that add unnecessary weight to all the inherent stresses of life, make them triggering, make them expand in volume.

On a good day, my cup is perhaps 80 percent full. I am stressed, but I can handle it. The day progresses. On a bad day, perhaps one in which something triggers my PTSD, my cup overflows: I cry over the proverbial spilled milk not because I am sad about the milk but because my cup was already nearly full, and the milk was more than my mind could handle—it was too busy dealing with processing my traumas while also dealing with the stress of any normal day.

The reason physical activity has become so important to me, especially since experiencing some major psychic traumas years ago, is because it has been an effective way to reduce what’s in my cup. Whatever the particular mix of liquid I was dealing with on a given day, physical activity acted as a siphon, removing perhaps 10 to 30 percent of the load each day and sending it down the drain.

There are two problems with this strategy of emotional regulation though...