If you've been doing the same strength-training exercises for months, your muscles may be in a holding pattern.
"To add distance or increase speed, your cross-training efforts need to push your limits," says Michael Silverman, a physical therapist at the Sports Rehabilitation and Performance Center at New York City's Hospital for Special Surgery.
These tweaks will help you develop new power for your run.
(Looking for new exercise moves to try? These Workouts Borrowed From Other Sports will make cross-training fun.)
More: Strength Training to Improve Running Economy
Planks
Tweak: Add Leg Swing
Holding a plank position—resting your weight on your forearms and toes, with abs pulled in—lift your right toes off the ground and swing your right leg to the side, toward your hips. Return to the start position and perform on the other side. Do 15 reps on each leg; rest and repeat twice.
How Fit Are You? Find out with these four self-tests of your overall fitness.
More: 6 Power-Training Exercises for Runners
Leg Lift
Tweak: Add Arm Swing
Stand with arms out in front of you. Extend your right leg in front of you and slowly lower yourself into a squat position. Pause, then slowly push yourself up to standing. Do this exercise in front of a mirror, checking that your knee doesn't turn inward. Do 15 reps and switch legs. Do three sets of 15 reps on each leg.
(Plus: Try these 4 Moves for a Stronger Upper Body, too.)