High-Impact Exercise Is Actually Good for Your Bones
From yoga and pilates to aerobics and boot-camp classes, the exercise industry loves to tout the “low-impact” nature of workout routines. But while low-impact exercise certainly has its place, you might be doing yourself a disservice by avoiding high-impact activities. It might seem counterintuitive, but high-impact exercise helps build stronger bones. Here’s how.
Everyone knows that you need to stress your muscles to make them get stronger. What you might not know is that the same is true of your bones. After all, your skeleton is as much a living part of your body as your muscles are, and it changes and adapts in response to everything you do. That’s obvious when you break a bone and it heals over time; it’s less obvious when an athletic kid grows up to be a senior with strong bones.
A perfect illustration of how impact is linked to sturdy bones comes from a study published in 2012 by researchers at the University of Bristol and Manchester Metropolitan University. The team combed through data in the Avon Longitudinal Study of Parents and Children (ALSPAC), which tracked the health of 14,500 families over two decades. Importantly, portions of that study had participants go about their everyday activities while wearing an activity tracker with an accelerometer, which analyzes g forces (a measure of impact).
The team honed in on accelerometer and bone mass data from more than 700 teenagers in the study and found that those who experienced impacts of 4.2 g or greater had significantly stronger hip bones. That’s comparable to the force you’d feel around a tight turn on a rollercoaster. To achieve that kind of force, you’d need to jump onto and down from a box at least 15 inches (38 centimeters) high or run at a pace of 10 minutes per mile (about 6 minutes per kilometer) or faster. Even though the teens rarely experienced those impacts, just the fact that they experienced them at all appeared to be enough to strengthen their bones.
We also have direct evidence from athletes who withstand most of their impact with only one limb: tennis players. When researchers from the UK and Germany performed bone-density scans on the right and left arms of 50 youth tennis players, they found that the bones of each athlete’s racket arm was around 20 percent wider and contained 40 percent more bone mineral than their other arm. You can also compare the bones of athletes whose sports require high and low levels of impact: a study of 255 young women found that while those who did high-impact sports like volleyball, hurdling, and soccer had a bone mineral density up to 29 percent higher than their nonathletic counterparts, those who did low-impact sports like cycling, swimming, and cross-country skiing had about the same bone density as people who didn’t exercise.