Jeff Galloway, the Olympian and pioneer of the run walk training method, has died at the age of 80.

Runner’s World reported that Galloway died Wednesday from complications related to a stroke and brain bleeding.

Galloway became a key figure in the American running boom of the 1960s and 1970s.

After qualifying as what he once described as an “unlikely Olympian,” he devoted his life to promoting the sport and encouraging everyday people to run.

He is best known for developing the run walk method, also called the Galloway Method or “Jeffing,” which encourages runners to include walking intervals during training and races.

The approach helped thousands of beginners complete marathons and long distance races.

Over more than five decades, Galloway founded running stores, training groups, camps and travel programs.

He also helped create major races, wrote best selling training books and became one of the sport’s most in demand speakers.

In later years, he embraced podcasts and social media to continue teaching new generations of runnres.