Backward running is a less natural motion, but can be accomplished with some speed with practice. It is better to start out backward walking (also called retropedaling) which is relatively easy, and speeding up. Like normal running, running up and down hills backwards will add an additional degree of difficulty.
Running backwards up a hill is not very dangerous. It will always be at a lower speed due to the enhanced difficulty, and if one trips there is less of a distance towards the ground and it is easier to absorb the impact with the arms and buttocks so that the head is not as likely to hit.
Running backwards down a hill is more dangerous, and it is advised that someone learn how to drop into a backward roll before attempting it, to deal with any resulting tripping or loss of balance in the prone movement. Although the distance to the ground is greater running downhill backwards, the incline makes it much easier to perform rolls in downhill running, than when running level ground, so it can be done more instinctively. This applies to backward running and the backroll as it does to front running and the front roll.
Turning the head around while running can generally eliminate the visual impediment, although it is awkward, limits speed, and may result in neck strain.
Practicing tumbling and exerting force in a backwards direction with the arms through various exercises like crab walking or planches may aid in stopping damage or injury from falls or stopping falls.
While downhill backward running is essentially the reverse of uphill running, and uphill backward running of downhill running, they are different in that the fibres would fire differently due to differences in the isotonic motions. The former is an eccentric version of a concentric movement, and the latter is a concentric version of an eccentric movement. Both concentric and eccentric movements have advantages in training, which is why most weight lifters perform both for set times.
With all forms there is an obvious backward lean relative to normal running's forward lean, which can shift the stress of the other muscle fibres a small degree.
Other advantages to backward running are a reduction in fear related to the movement, a form of exercise that is naturally more reserved, gains in balance, and the general enjoyment resulting from entertaining activities like these. Due to constantly having to look behind oneself, or sometimes keeping the eyes fixed, people can learn to run with more neck mobility or without a straight look ahead. This can stress the neck muscles which can be dangerous if done too aggressively, but in the long term could lead to adaptations in them.
Backward running adds another dimension to running, and when complimented by sidestepping in both directions (with and without crossovers front and behind intermittantly) covers the essential dimensions of human movement on the two-dimensional plane. Diagonal movement as well as curving running (as is done on long race tracks like 200m+ in the Olympics) are additional forms of running.
Backwards running allows referees in sports such as football or rugby to continuously observe an area of play without interfering with play.