From a Wall Street Journal article by Jen Murphy:

Gravel riding is more jarring than road riding so strength and mobility really come into play. “Your upper body takes much more of a beating,” Mr. Wilwerding says. “Especially when you’re riding bumpy terrain for eight hours.” With the help of a coach, he has trained to participate in five century rides—three road, two gravel—this summer. His next ride, the SBT GRVL, takes place Aug. 18 and covers 141 miles and about 9,000 feet of climbing in Steamboat Springs, Colo. “I’m in the best shape of my life outside of my collegiate swimming career,” he says.

When Doug Wilwerding wanted to mix up his long-distance cycling routine two years ago, he considered mountain biking. Then 54 years old, he was deterred by the potential for injury from dodging rocks and roots while flying downhill. Instead, he took up gravel riding, a relatively new sport where you ride on unpaved roads, including dirt, gravel and mixed-surface terrain.

Read more by clicking on the link below:

https://www.wsj.com/articles/a-cyclist-turns-to-gravel-to-stay-fit-11562497260