Over the years, bass drumming has gone through many stages. Gene Krupa and Buddy Rich amazed the masses with their hand speed, but little attention was paid to their kick foot. Jazz drummers like Ed Shaughnessy began using double bass drum set ups in the 40's and 50's and rock drummers like Ginger Baker, Keith Moon and Carmine Appice made the double bass drum setup popular.
The creation of the "slave pedal" allowed drummers to have 2 beaters hitting one bass drum, allowing for smaller setups without sacrificing the double bass ability. The use of the double bass is predominant in heavy metal, death metal and punk music. There are 3 predominant playing styles for the bass drum pedal.
The first is the "heel-toe" technique. The technique allows a drummer to play two strokes in a single motion. It consists of two parts. First, the foot is suspended above the footboard of the pedal and the first of the two notes is played with the ball of the foot. Then, the foot snaps forward, the heel comes up and the toes complete the second stroke. This technique allows for rudiments to be played with the feet, as well as increased speed.
The second is the slide technique, in which the pedal is struck around the middle area with the ball of the foot. As the drum produces a sound, the toe is slid up the pedal. After the first stroke, the pedal will naturally bounce back, hit the toe as it slides upwards, and rebound for a second strike.
Of course, many drummers like simply using the flat foot technique, which simply applies the majority of the foot to the pedal, and only the heel is elevated slightly off the pedal. This method utilizes more muscle groups than either of the other 2 methods. It also relies more on repetition and less on "technique".
The great thing about double bass drumming and the various techniques is that there is no right answer and no wrong answer. It is all about personal preference. If you tallied up the most amazing drummers in the world, you would be able to find each technique in use. What works for one drummer doesn't always work for another drummer - this led to all of these inventions and techniques being created.