IT'S A COMMON misconception that speed is entirely based on the genes your parents provided you. True, your ratio of fast- to slow-twitch muscle fibers defines your maximum potential, but most of us are slow only because we're rusty. "It's a muscle memory thing," says Donald Chu, director of performance enhancement at Stanford University. "If you don't practice speed, it will desert you." To avoid that, you need plyometrics—jump training—which is the most proven way to refresh your muscle memory.
"Plyometrics teach your muscles how to go from responding pliantly, like a tomato, to elastically, like a superball," says Jimmy Radcliffe, co-author of High-Powered Plyometrics. This month, to give yourself more bounce to the ounce, you'll begin endurance workouts on Monday and Friday with a ten-minute plyometric workout (see "Upward Bound"). Starting with basic movements (jumping up to a box and stepping down) and progressing to more complex moves (dropping off a bench, landing, and then jumping straight up), you'll relearn the movement required to, say, avoid slamming into a tree while carving a backcountry glade. For sports that require upper-body quickness, such as kayaking, medicine-ball drills—chest passes and overhead throws—will provide plyometric action for your arms and torso. "Whether you're a climber or a skier or a mountain biker," says Stanford's Chu, "plyometrics will help you get out of unexpected situations fast."
As your quickness improves, you'll also need to develop your "reserve speed," says Peter Twist, a National Hockey League conditioning coach and founder of Twist Conditioning. "The kind of speed you get in third or fourth gear." How? Practice high-intensity, Zone-4 intervals, then chip away at the length of your recovery times. On Wednesdays, sometime toward the end of your endurance workout, launch into a full sprint for 30 seconds. Resume running or cycling, and when your heart rate returns to Zone 2 on the heart-rate scale, do another 30-second sprint. Start with three repetitions and work up to six or eight by week 16 (see "Plug Yourself In"). Next month you'll reduce the recovery time between sprints. The drill develops your reserve capacity for speed by reestablishing the neurological pathways needed to turn on the afterburners when you're fatigued.
Combined, sprints and plyometrics will get you off the starting line quicker and give you overdrive power to finish a race strong. And trust us, your muscles will remember—you can't blame mom and dad forever.