A trio of Massachusetts ultrarunners who broke through the 100-mile barrier for the first time in 2019 closed out the year by doing so again — only this time they passed on the trails and tackled the distance on the mind-numbing terrain of a treadmill.

David Shanahan, Philip Petschek and Marie Gryszowka all completed 100 miles or more as part of the Dreadmill 48-Hour Endurance Challenge. The format of the event allowed runners to choose a 48-hour time period of their choosing in December to complete as many miles as possible on a treadmill. They were required to document their efforts by taking a photo of the proof of distance each time the treadmill stopped, with a timestamp validating when the mileage was completed.

Runners could choose to run 100 miles, or they could select a 48-hour race with unlimited mileage.

Shanahan opted for the 100-mile option. The 39-year-old from Auburn, Mass., logged his first two 100-milers this year with 100.7 miles at the Notchview Ultra 72-Hour race and 100.23 miles at the Beebe Farm 48-Hour event. Shanahan took on the Dreadmill challenge and finished 100 miles in 44:51:00. Of the 33 runners who took on the 100-mile option, 28 finished the distance, led by 46-year-old John Cash of Washington, Mo., who finished in 14:35:24. Ellen Cottom, 45, of Portsmouth, Fla., was the fastest female, finishing 100 miles in 21:29:00.

Both Petschek and Gryszowka took part in the 48-hour event. Of the 42 participants in that event, 28 completed 100 miles or more. Chad Wolf, 30, of Cincinnati, Ohio, led all runners with 174.01 miles. His closest competitor, 61-year-old Davy Crockett of Saratoga Springs, Utah, finished with 164.1 miles. Teri Lemke, 59, of Loudonville, Ohio, finished seventh overall and covered more miles than any other woman with 120.97 miles.

Petschek, 58, of North Andover, Mass., finished 18th overall with 102.59 miles. It was his second 100-plus-mile performance ever, the first coming in the Notchview 72-hour race in July when he ran 104.5 miles. Gryszowka, 35, of Spencer, Mass., also finished her first 100-miler at Notchview, logging 114 miles in 72 hours. She completed an even 100 miles on the Dreadmill, tying for 25th place overall.

Two more New England residents took part in the 48-hour event but did not hit 100 miles. Bennjamin Griffin, 33, of Pittsfield, Mass., completed 55.5 miles during the two-day event while 49-year-old Michael Crutchley of North Stonington, Conn., completed 31.17 miles.