Years of studying elite runners in freeze frame video clips have revealed certain truths about optimal form. Both sprinters and distance runners alike can benefit from exercises that duplicate the distinct joint and limb movements, as well as the range of motion, of these athletes.

Try the following exercises using resistance tubing secured to a stationary object such as a post, or secure them with an Active Cord attachment, available at most sporting goods stores. (Resistance tubing comes in varying degrees of tension; be sure to try several in-store before purchasing.) The resulting strength, flexibility and muscle memory will improve your running form, stride length and explosiveness, which will mean faster race times.

Each of the exercises below is preceded by a few words about form. In addition to these tips, avoid rotating your torso or shoulders as you run. This, in turn, will keep your hips square so that your pushoff forces you directly forward.

To run well, great ankle joint extension is necessary, as this increases the power of your pushoff. The more you can extend, the better. During running, keep the knee slightly bent in the pushoff leg to maximize horizontal force. A perfectly straight leg results in more of a leap and is a waste of force.

Heel Raise

Secure the tubing under the balls of your feet. Fasten the ends to an Active Belt around your waist or to a post, or have someone assist you by holding the ends. Stand on the balls of your feet and lower your heels until you feel a stretch in your Achilles tendon (there is no need to push the heel beyond the point where you first feel the stretch).

Rise up as high as possible and hold for one to two seconds. Perform 10 repetitions. This exercise is best achieved standing on a stable board two to four inches from the ground.

Forward thigh drive increases stride length and the power of your pushoff. Hip flexors, located in the front of the hip are largely responsible for this, and you can benefit from strengthening them.

Hip Joint Flexion

Inhale and hold your breath as you drive your thigh forward. Keep your knee bent so that your shin remains parallel to the ground until your thigh is past vertical position. Do not drive the thigh all the way parallel to the ground, as this will teach you to drive your thigh upward rather than forward when running. Therefore, it's also best to add an additional cord for more resistance than to rely on a greater stretch of the tubing as you become stronger.

Turning over, such that your feet are in contact with the ground more often, provides more force-generation, allowing you to go faster. Cutting short your time in the air, however, reduces the extent to which you are using that generated force.

Therefore, during flight phase, do not drop your thigh as it reaches its highest point and the forward leg begins to straighten. Only after straightening should the leg come back and down. Aim to land with your landing leg close to the body's center of mass--for distance runners, this means only slightly in front of you. For sprinters, your leg should be more or less directly underneath you.

Combined with a full-foot or even ball-of-foot landing, this running technique will generate the least amount of braking force at the point of contact and keep you moving fast. The greater the angle between your legs midflight, the faster the results. The best sprinters open this angle up to as much as 165 degrees; distance runners employ a slower and more economical form, which means a maximum angle of about 100 degrees.

Hip Joint Extension

Attach the tubing to a high stationary object. Stand in front of it and attach the free end to your ankle. Stand with your leg raised, thigh slightly below parallel.

To begin, straighten your leg and pull down until your foot touches the ground beside your other leg. Perform this action vigorously for 10 repetitions. As you become conditioned, try balancing yourself (instead of holding on to a wall or stable object) to achieve even greater results.

Lunge

The down position of the lunge duplicates the airborne position in sprinting. This exercise will also stretch the hip flexors. With your feet hip-width apart, step forward with a very long stride. Upon landing, slowly lower your upper body straight down. Shift your weight backward and extend your forward leg. Return to your standing position and repeat with the other leg for 10 repetitions each.

In addition to the lower body workouts discussed here, there are a variety of lower-back, abdominal and upper body exercises that will increase your strength and improve your form. Coupling these sport-specific exercises with regular speed work will give you even more dramatic improvements in running speed.

Adapted from Explosive Running by Michael Yessis, PhD, Contemporary Books, Chicago, IL, 2000, 173 pp. $17.95.

? American Running Association, Running & FitNews 2003, Vol. 21, No. 5, p.2