An international team of physicists has identified the ultimate technique for using playground swings, and I’m happy to report that you may have been doing things right all your life.
In their paper “Initial phase and frequency modulation of playground swings,” published in the journal Physical Review E, Chiaki Hirata and four other physicists from Japan and Australia compared different mathematical models and real-world swing data collected from volunteers to determine the most efficient way to swing. mode, as follows:
At the beginning of the swing exercise, when your momentum is low, keep leaning back as the swing moves forward beyond the balance point (i.e., when the chain is vertical).
Once you do get going, the best point to start leaning backward is much earlier – at the highest point of the backward swing, just before you start moving forward.
To be fair, the focus of the Hirata et al. study was not to determine the optimal swing efficiency on the playground, but to provide a more realistic model for the field of swing physics research (the real thing, I assure you). The paper compares their own swing model with a “fixed frequency” swing model and a “square wave” model and finds that the combination of the two produces results that are closer to real-world swings.
How do you know how to swing a club?
If you read the above and think, “No shit. I’ve been swinging like this since second grade,” it might be valuable to consider how you learned to swing in the first place. Using a playground swing (or “dynamically coupled oscillator,” according to science) is hard to describe precisely, and how we can swing so easily is quite mysterious.
To paraphrase this paper: it’s relatively simple to choose the right time to shift your center of gravity during a swing cycle, but the window gets shorter each time the swing goes back and forth to gain momentum. Their example shows a 7 millisecond change per cycle – a very short reaction time – but as kids, we somehow manage to master the swing quickly without having to think about it.
The explanation the scientists propose is that our bodies adapt to the centrifugal forces at work, and that during the swing we subtly change our movements in response to the forces acting on us without really being aware of it. Imagine trying to describe exactly how to swing to someone who is not on or has never seen a playground: “Like, when you think it’s time to lean back, you lean back-“
The paper suggests further research into using virtual reality swings to eliminate the variables of physical feedback, assuming that without momentum and other forces guiding our movements, we would have a hard time achieving high-speed swings. I, for one, eagerly await these breakthroughs in the new frontiers of swing-based experimental physics.
