Parenting is a pretty full-time gig. Finding time to do anything for yourself can seem almost impossible, never mind exercising. But if your kids are little, then you don't need to worry because running after them is a full-time workout in itself. Bending down to pick up the constant trail of litter they leave behind them are the only squats you'll need. Here are some hilariously relatable tweets from parents about the harsh realities of fitness (or lack thereof) once kids come along.