Fosbury continued to refine his technique, developing a curved, J-shaped approach run. This allowed him to increase his speed, while the final "curved" steps served to rotate his hips. As his speed increased, so did his elevation. Fosbury made little to no use of his arms at takeoff, failing to "pump" them upwards, keeping them down, close to his body: the next generation of floppers would add an arm pump. Fosbury's key discovery was the need to adjust his point of takeoff as the bar was raised. His flight through the air described a parabola: as the bar went up in height, he needed more "flight time" so that the top of his arc was achieved as his hips passed over the bar. To increase "flight time," Fosbury moved his takeoff farther and farther away from the bar (and the pit). Jumpers have a natural tendency to be drawn in closer to the bar and it requires mental discipline to move out, rather than in. By way of comparison, classic straddle jumpers plant their take-off foot in the same place every time, less than one foot away from a line parallel with the bar. Photographs of Fosbury attempting heights above show him taking off nearly out from the bar.