I saw this and laughed-
Victoria’s Circuit, A Sports bra capable of powering an iPod during a normal workout-
Harnessing the untapped power of breast motion. - By Adrienne So - Slate Magazine
If you’ve ever watched roller derby chicks then you will know this is an idea worth exploring. 
I found this most notable-
This may be a start toward solving the energy crisis.
Wow..that’s an awesome little article. I’m already envious of women’s breasts, sigh…if I could charge my phone by jumping up and down a few times…let me tell ya. 
I suppose at least some of these girls in LA have a more..practical reason to get those implants.
LOL! Heh. When I was your age…we didn’t wear bras. 
Of course now I haveta stand on my hands to get 'em up where they use to be. J/K…kinda.
'60’s Hippy??
Not quite that old, old man.
'70’s…highschool/college…I wore the appropriate attire and had the requisite loooong hair. However, you’d be hard pressed to call me a hippy.
Bra less, mabbe…hippy notsamuch. Though I’m all for Peace and Love. 
How 'bout you, Jim, were you a hippy? Have ya exhaled yet?
It would be a simple matter of converting the mechanical stresses placed on the supporting members of the bra into piezoelectric energy.
Of course it would have zero practical utility unless you want to look like a Borg.
Maybe you should try this idea with a certain body part exclusive to men. Same idea right? There are two of them and they move around during exercise
I was just thinking the same thing! Just change out your athletic supporter for some boxers. Then all the guys could brag about how fast their iPods charge…
Totally!