SICK OF IT: The same old routes
MIX IT UP: Throw in timed intervals and sporadic pace changes. Sprint for 20 seconds every time a red car passes you. Reverse directions on your favorite loop. Or do a one-way route—go as far as you can in one direction and arrange for someone to pick you up. Really need a change of scenery? Bring a GPS and draw something with your track. "You can get in a funk just doing the same thing every day," says Goucher. "Try something totally new."
SICK OF IT: Working out indoors
MIX IT UP: TV can help you pass the treadmill time in more ways than you think. Designate a buzzword and do a 30-second sprint every time you hear it. (If you're feeling strong, try "deficit" on CNN.) Or go hard during commercial breaks. If that doesn't work, add to the challenge. Unlike a stationary bike, mounting your ride on CycleOps Aluminum Rollers with Resistance ($360; cycleops.com) will have you focusing so much on balance that you won't even notice the clock.
SICK OF IT: Hard workouts
MIX IT UP: Stack your Shuffle with high-energy tunes. A team of British scientists recently demonstrated that the faster the pace of the music you listen to, the harder you go: a 10 percent increase in the tempo of a song led cyclists to exert 3.5 percent more power and cover 2.1 percent more distance in the same time. Start with runningmusicmix.com, which offers preset playlists of songs arranged by beats per minute. The Motion Traxx podcast releases free high-bpm mixes crafted for working out; Podrunner Intervals goes a step further and sets a soundtrack to your speed workouts, interspersing fast music with slow-paced breaks.
SICK OF IT: Early-morning training sessions
MIX IT UP: Buy the Brookstone Rise & Shine Natural Wake-Up Light ($100; brookstone.com). A progressively brightening light will trick your brain into producing more cortisol and adrenaline, which help you wake up. Schedule a buddy to meet you at least once a week—you'd bail on yourself, but you won't flake on a friend. "If you have to get out the door when it's zero degrees and still dark, you're more likely to do it if someone is waiting," Galloway says.
SICK OF IT: Everything about training
MIX IT UP: Turn workouts into playtime. Here are three fitness games that can help:
SIGN UP FOR A LOCAL HASH—an informal fun run in which you'll be asked to figure out the course on the fly, and finish with a beer (or several). Find a local group at gthhh.com.
SET UP A CHASE, with a weaker partner getting a head start proportionate to his ability. Or practice attacking: over a set distance, one partner surges and strikes to get away; the other tries to contain the attacks.
RACE YOURSELF. Garmin's line of sport-oriented GPS computers, such as the new Edge 800, for cyclists ($450; garmin.com), and the Forerunner 410, for runners ($325), let you to race against your past performances, a goal pace, or a track uploaded by a friend.