and quadruples were small. King conjectured that slowing their approach into the jumps were due to skaters' "confidence and a feeling of control and timing for the jump", rather than any difference in how they executed them. Vertical takeoff velocity, however, was higher for both quadruple and triple toe loops, resulting in "higher jumps and more time in the air to complete the extra revolution for the quadruple toe-loop". As Tanya Lewis of Scientific American puts it, executing quadruple jumps, which as of 2022, has become more common in both male and female single skating competitions, requires "exquisite strength, speed and grace". For example, a skater could successfully complete a jump by making small changes to their arm position partway through the rotation, and a small bend in the hips and knees allows a skater "to land with a lower center of mass than they started with, perhaps seeking out a few precious degrees of rotation and a better body position for landing". When they execute a toe jump, they must use their skate's toe pick to complete a pole-vaulting-type motion off the ice, which along with extra horizontal speed, helps them store more energy in their leg. As they rotate over their leg, their horizontal motion converts into tangential velocity. King, who believes quintuple jumps are mathematically possible, says that in order to execute more rotations, they could improve their rotational momentum as they execute their footwork or approach into their takeoff, creating torque about the rotating axis as they come off the ice. She also says that if skaters can increase their rotational momentum while "still exploding upward" they can rotate faster and increase the number of revolutions they perform. Sports writer Dvora Meyers, reporting on Russian coaching techniques, says female skaters executing more quadruple jumps in competition use what experts call pre-rotation, or the practice of twisting their upper bodies before they take off from the ice, which allows them to complete four revolutions before landing. Meyers also says the technique depends on the skater's being small, light, and young, and that it puts more strain on the back because they do not use as much leg strength. As a skater ages and goes through puberty, however, they tend to not be able to execute quadruple jumps because "the technique wasn't sound to start with". They also tend to retire before the age of 18 due to