There are now a wealth of sensors that can be integrated into garments, with the potential to turn your clothes into monitoring platforms or all the way through to smart attire. To help those intrepid enough to embark on such an adventure there is an excellent article from Kate Hartman on Make, that is both comprehensive and accessible. I certainly will be pointing my fashion design students at this. The page is here
An example below shows how to wire up a force sensor, as a resistive divider, to a lilypad and detect when a step is made.