I'm a 5'6, 120 lb female who also enjoys running and had to take the same precautions. . .until one day I got bored of exercising alone and decided to get a pet. I chose a scrawny, mangy "Lab mix" puppy from the shelter with crooked teeth and was told "she'll only get to 50 lbs." A year later she blossomed into a 75 lb Rottweiler with a fearsome-looking underbite (she's actually very sweet and friendly, but she looks TERRIFYING.) Haven't worried about my safety since!