When the werewolf sprints, it runs on all fours, and moves much faster than a horse. This is also useful for traveling great distances on foot.
If you kill a human you can 'Feed' on the corpse to regain some health and extend the duration of Beast Form. You will have increased speed, health, damage, and stamina. You will turn into a werewolf and friendly humans will attack you. To use your new ability, go to 'Magic', then 'Powers', then 'Beast Form'. After a few quests you are given the chance to become a werewolf. This is where the Companions are located. There should be a building that resembles a ship's hull. While standing on the steps looking at the doors to Dragonsreach, look to your right. Move through the town until you reach Dragonsreach, which is the castle. Leave your house and then go back in, the armor should appear on the mannequin and will still be in your inventory. Using the armor stand in your house in Solitude, place any piece of apparel on the mannequin then immediately take it back before exiting the menu.