Runners must touch the yellow gate as they leave for each loop. When they complete a loop, they must touch the gate again to officially finish. Once touched, they can go to their crew and recover.

Grant Park was flooded with a sea of runners Sunday morning — many donning festive green accessories — for the annual Shamrock Shuffle 8K race.

The Bay Area's Ninja Loop was founded by ultrarunners in San Francisco and stretches for 12 miles in the Marin Headlands.

Extra loop for runners Runners using the Bath Half as training for the London Marathon, are being offered the chance to do an extra loop of the course, taking the overall distance up to 18.5 miles.