Removing thresholds can be problematic, especially if you plan to reuse them. Remove thresholds either before or after the old flooring is removed depending on which is easier. For example, a threshold to a sheet vinyl floor typically must be removed before the flooring. A threshold to a carpet can be removed before or after the carpet depending on the adjacent flooring material. As with removing molding, start by carefully breaking any seals between the threshold and the adjacent flooring. Then insert a putty knife to lift nails or remove screws attaching the threshold. Even if you don’t plan to reuse the threshold, attempt to keep it intact as a possible pattern for a future threshold.
If that old refrigerator or other major appliance is just too big for you to move, hire a local mover to do the job for you. The cost will probably be less than a visit to the doctor. Alternately, ask a friend or relative with furniture moving experience to help. Also, make sure you use an appliance dolly with straps or a large two-wheel freight dolly. Make sure the straps go under any coils on the rear of a refrigerator or freezer as they can easily be damaged.