If you’ve always wanted to run for 24 hours straight, does Back on My Feet have a race for you! The Philly-based nonprofit uses running to help homeless people across the country get, well, back on their feet. This weekend the group hosts its eighth annual Stroehmann Back on My Feet in24 Philadelphia Race Challenge.

The race is around the Schuylkill, in four parts: the 24-hour ultra marathon, timed and distance relays, a 5K, and a midnight glow in the dark loop. (An ultra marathon is a run longer than 26 miles.)

Eight hundred runners will be participating, including 200 ultra marathoners and Back on My Feet members and alumni.

The ultra marathon and the relay challenge kick off Saturday at 10 a.m. at the Schuylkill River Running Loop (Lloyd Hall, 1 Boathouse Row). Or come out at midnight for the 8.4-mile glow in the dark race.

On Sunday at 8 a.m., the 5K runners get their turn.