Runners preparing to participate in the annual Shape Up Somerville Recreation Road Race this year may need a tad more training. The fifth annual race sponsored by the city is being held Sunday, April 13, and the course will be extended from its 2.7-mile length of years past to a full 5 kilometers, which is 3.1 miles. A 1-mile fun run for children will also be held at 10:30 a.m., followed by the 5K at 11. Registration is open to all community members for a fee of $5 for children under the age of 10, and $20 for adults. The fee includes a T-shirt, refreshments, and a celebration after the race. Registrations can be submitted online at www.somervilleyouthrecf.org or by visiting City Hall or the Recreation Department at 19 Walnut St. for an application.