Off they go!

Thousands of energized bodies took off from outside the Miami-Dade Arena and traveled down Biscayne Boulevard more than an hour before sunrise Sunday for the 21st running of the Life Time Miami Marathon and Half Marathon.

The 26.2-mile full marathon and 13.1-mile half marathon event, with a combined field of 18,000 registrants, will proceed together along the same route until the half marathoners return to the finish down the street at Flagler and Biscayne near Bayfront Park.

The rest of the field will remain running the longer distance until they return to the same finish.

Conditions at the predawn 6 a.m. start: 74 degrees with 74-percent humidity and winds from the east at 13 miles an hour.

As usual, hundreds of spectators gathered on the stairs leading to the arena or lined Biscayne Boulevard hoisting hand-written signs for their favorite competitors. The Freedom Tower across the street was bathed in red lights, a few red flares went off and pictured on the massive LCD screen outside the arena were encouraging messages to the participants beginning their journeys with tiny steps until they could spread out.

The course heads toward Miami Beach over the MacArthur Causeway past lit-up cruise ships, down famous Ocean Drive through South Beach, past the Miami Beach Convention Center, over the Venetian Causeway and back into Miami where the half marathon finishes and full marathon continues into the Brickell and Coconut Grove areas before ending near a festive Bayfront Park.

The half-marathon winners are expected to cross the finish line a little over an hour after the start.

The marathon winners are expected to finish more than an hour after that – at about 8:10 or later for the men and 8:30 or later for the women.

This story will be updated as the winners in both events cross the finish, and also after the event ends in the afternoon.