When Bart was first seen in Run, he had short blond hair, wore a red hoodie, yellow cargo pants, red running shoes, and was constantly seen with his red-lightning bolted backpack. He is currently 5'11" and weighs 175 lbs.
Impulse in Doomsday
Added by SuperBlahBlah
When he returned in Justice he had curly brown hair and his facial features matured. He still continued to wear his primary costume colors of red and yellow.
When he was last seen in Doomsday, Bart looked slightly older and he still wore a red and yellow combination of clothing and had shorter hair than in Justice.
As Impulse, Bart wears a costume slightly similar to Oliver's Green Arrow outfit. His costume includes a red vest with a hood that has yellow lightning designs on it with a lightning bolt on the back. Underneath that he wears a long-sleeved dark red shirt with a pair of dark red jeans, a dark red belt and red shoes. He also wears a red cuff around each wrist and a pair of red sunglasses
When I'm asleep, I'm just as slow as everyone else. - Bart Allen, Run
At first, Bart was impulsive, irreverent, and unconcerned with laws or property. Whenever possible, Bart financed an extravagant lifestyle with stolen goods and credit cards as he hates to sleep outside. Now Bart is more concerned with people's well-being. He also seems to have an obnoxious sense of humor and is very flirtatious towards women, especially Chloe.
When Bart was young, he was in an accident involving a bright flash of light. In turn, he realized he could move at incredible speeds having improved super fast reflexes.
Bart escapes from Clark
Added by Babygogeta
Bart running on water
Added by NatDuv
Super speed: Bart can run, exercise, or move his body at overwhelming speeds; he can run and sprint at superhuman speeds. Bart Allen can run at near lightspeed, so he can run on water, pass through objects and is as fast as Clark Kent. (Run, Justice, Doomsday) In fact, based on the outcome of Clark Kent's past attempts to "catch" him, it is likely that Bart's top speed relative to Clark, is at least comparable to Clark's top speed relative to the average human, and possibly even faster.
Super Stamina: Bart can run and exercise for long periods of time without getting too tired. However, this endurance is not unlimited, and running too long can overtax his body. (Justice)
Intangibility: According to Toyman's files, Bart can move fast enough to pass through solid objects.
Super Metabolism: Bart can consume vast quantities of food without gaining weight. This is because he burns off the food considerably faster then normal people due to the speed he runs, meaning he also needs to eat more then other people to keep himself from being fatigued. (Justice)
Also, when he uses his ability too long, his nose begins to bleed and when he is severely depleted of energy and is unable to use his super speed which is shown in the episode Justice. He is also shown to have a supercharged metabolism that requires an abnormally high caloric intake shown again in Justice.