Possible or not?

Starting the day with exercise is real fun..and burning out those extra calories can sometimes be very painful !!
Gym has become some kind of necessity in urban people's life. Being an "uRban hopeless Crap" I start the day with Gyming and flexing my muscles with all those dumbles and benchpresses..
Today only i was kinda training in the Gym and just then current went off..It was not that extra special thing that happens..we ppl are used to it..

Just then i saw a person using the mechanical treadmill and just next to him there was a person paddling the exercycle.Just got a crazy idea then..

Can that energy be used in making electricity?? I guess i read it somewhere in my physics textbook.." energy can be transformed from one type to another type" !!
So can the mechanical energy of the ppl burning out those calories be converted somehow into some usable form ..??I am not thinking Big.. may be it can fulfill the power requirements of the Gym,,