It's easy to think that all the best training ideas come from the world of running. But distance running is part of a wider universe of athletics, so why not borrow from the toolboxes of other sports that require some combo of endurance, speed, and strength? "If all you do is run, you're failing to develop all of your muscles and limiting your range of motion," says Dennis Barker, coach for Team USA Minnesota, an elite distance-running program. These workouts taken from the training plans of other sports will lead you to better fitness, sharper speed, and a stronger body.

BORROW FROM BOXING: ROPE "RUNS"
"Fast feet are as important as fast hands for boxers, so they've jumped rope for centuries to develop this skill," says Ross Enamait, a boxing trainer in Vernon, Connecticut (rosstraining.com). "Jumping rope also helps runners be light on their feet." Quick jumping helps increase stride frequency and leads to greater muscle endurance, aerobic conditioning, and power, says Enamait.
THE WORKOUT
Jumping rope can challenge even the conditioned runner, so start conservatively with six stints lasting 30 to 60 seconds each. Run in place, focusing on high knees. Rest 30 to 60 seconds between each round. Build up to three minutes.

Shoes & Gear
Cyclists practice their "spin"—similar to a runner's turnover—to hone their cardiovascular fitness. "The optimal cadence for both cycling and running is 90 to 100 revolutions per minute," says Terry Martin, a running, swimming, and triathlon coach in San Diego (multi-sports.com). (A "revolution" for runners means right-foot-left-foot-right foot.) Because of this similarity, Martin recommends runners use spinning intervals to reinforce brisk leg turnover and get a rigorous cardio workout without the impact stress on your joints.
THE WORKOUT
Pedal easy for 15 minutes. Shift into a slightly harder gear and spin for two minutes at 95 to 100 rpm (count how many times your right knee comes up in 10 seconds and multiply by six). Then pedal at 80 to 90 rpm in an easier gear for two minutes. Repeat five to 10 times. "These intervals should feel as challenging as running 400s on the track at 5-K race pace," says Martin.

BORROW FROM GOLF: CORE STRENGTHENING
"A strong golf swing requires a stable, powerful transfer of energy from legs to arms through the core," says Kat Brown, a collegiate golfer turned personal trainer at the Harvard University Recreation Department. Runners who adopt a golfer's focus on developing strong glutes, hips, abs, and lower back can strengthen weak muscles, which can translate into fewer injuries, says Brown.
THE WORKOUT
Do 12 to 15 reps of the following: Bird dog On hands and knees, extend right arm forward and left leg back until parallel to floor. Hold. Return to start position. Extend opposite arm and leg. That's one rep. Russian twists Holding a three-to five-pound medicine ball, lie on back, knees bent. Lift torso 45 degrees from floor. Twist torso right then left for one rep. (Do it without a ball by extending arms forward, clasping hands, then twisting.) Treadmill Walking Workouts With hands on hips, balance on left leg. Bend forward and lift right leg behind you, keeping it straight. Hold for two counts. Return to start. Repeat, then switch legs.

Treadmill Walking Workouts
Upper-body exercises help swimmers develop the strength and endurance necessary to push and pull through water's resistance lap after lap. "Whether you run or swim, building upper-body strength helps you hold your form even when you tire in the latter part of a workout or race," says Martin. Sure, you run with your lower half, but "the legs follow what the arms do," she says.
THE WORKOUT
Hold a pair of light dumbbells and stand with your right leg forward. Very slowly, swing arms as if running. Pump 20 times. Rest one minute, and then switch legs and repeat.