I find that the best leverage for removing stubborn pedals is to straddle the rear wheel, put your shoulder on the saddle, have the pedal to be removed in the forward position, align the pedal wrench with the crank arms (within 20 degrees if possible), and hold the opposite pedal for leverage. A rag in the wrench hand can let you apply more leverage without undue pain. A nice long pedal wrench is essential (not all pedals can take an allen). Don't forget to grease the threads when installing pedals so they will come off easier next time.