NEW YORK (Reuters) - Man versus machines? In the realm of fitness at least man seems to be winning.

    Despite a gym floor bulging with weight-lifting equipment, fitness experts said the only thing people need to push, pull and lift is the weight of their own body.

    "If more people knew you could get a good physique using your body as a bar bell, they could take matters into their own hands," said Bret Contreras, author of "Bodyweight Strength Training Anatomy," a guide to bodyweight-only workouts aimed at everyone from the exercise-challenged to the personal trainer.