That treadmill load (700 lbs treadmill, 300 lb person, weight distribution 2/3 to one end) will be 200 psi, on concrete which is good for at least 2500 psi. The psf on the footprint drops to 1000 lbs/(3' x 7') or about 50 psf. Also, note that at 250 lbs per leg, the effective point load is roughly the same as a 250 lb person standing on one foot. These are VERY small loads.
ASCE 7-10 for "Recreational uses - Gymnasiums" seems to be the logical choice, at 100 psf. At 100 psf, the unreduced load accounts for a sudden loading/impact premium of 100%, over the ENTIRE floor area.
Remember that parking garages are designed for 40 psf, even though the wheel loads can be upwards of 1000-1500 lbs each, and the point load design criteria is 3000 lbs., specified for jacking load (see the footnotes to the table.) The design of the slab for point/small area loads if you desire or need to do so is far different from designing an entire floor for such a high load.