USS Biomechanics Director Australian Kieren Perkins ' remarkable distance swims have several characteristics that seem to be important to fast distance swimming. One of them is that he is still able to maintain very similar body position from the beginning to the end of the race. Although his stroke rate increases, his body position is similar.
Body roll allows swimmers to utilize the trunk muscles in the generation of stroke propulsion.
Additionally, it may also have streamlining benefits. The left arm is able to create significantly higher propulsive forces due to a more streamlined entry into the water and a stronger insweep phase. During the last 100m, there is evidence of fatigue in the pulling patterns. There is, however, a maintenance and even a slight improvement of propelling efficiency. Possibly toward the end of the race, neuromuscular, learned patterns are the dominant factors in his technique.