Stock photography, photos: A man trail running in winter Stock photos of A man running in the back country in winter in the Sierra mountains of California.. Photograph: © William Stevenson Click for a larger image and more information Keywords associated with this stock photo: Running, runner, run, training, back country, action, active, effort, energy, liveliness, speed, determination, momentum, motivation, strength, aerobic, desire, adventure, freedom, man, male, winter, snow, mountains, California, vertical, snowy, cold, Outdoor, outdoors, outside, sports, sporting, sport, exercise, physical, fitness, outdoorsman, sportsman, adult, young, adventure, adventuring, twenties, 20, s, 30, thirties, one, 1, person