A new study conducted by physicists has revealed the best technique for maximizing swing height on a playground. The researchers found that the key is to lean back at specific moments during the swing’s motion. Children seem to intuitively understand this concept, even without knowledge of the underlying physics.
The team, led by Chiaki Hirata at Jumonji University in Japan, developed equations to describe the swing’s motion while taking into account the swinger’s ability to lean forward or backward. They then solved these equations for different swing sizes and sequences of upper body movements. Through their calculations, they identified the combination of movements that allows the swing to reach the highest altitude from one oscillation to the next.
According to the findings, when the swing’s arc is small at the beginning, the swinger should lean their upper body backward as the swing moves forward at the bottom of the arc. As the swing gains height, the swinger should start leaning back earlier, when the swing is at the furthest point of the backswing.
To validate their model, the researchers built a swing in the lab and enlisted 10 college students to test it. These students had previous experience with swings but were not taught any specific techniques for maximizing swing height. The researchers attached markers to both the swing and the participants to track their motions and recorded the swinging using a camera. Analysis of the footage revealed that the students’ movements aligned with the rules derived from the mathematical model.
Chiaki Hirata highlights the remarkable ability of swingers to adjust their body position quickly. The researchers speculate that this may be an unconscious response to a centrifugal-like force pushing them back. To investigate further, the team plans to conduct experiments using virtual reality swings, where such forces can be manipulated.
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