Some people believe that runners should complete numerous sets and many repetitions with light resistance to enhance their endurance capacity. However, this is not our purpose in performing strength training. Remember that running is best for improving cardiovascular endurance, and that strength training is best for increasing musculoskeletal strength.

Generally, muscle strength is best developed by training with moderate weightloads (about 75 percent of maximum) for 8 to 12 repetitions per set. However, distance runners typically possess a higher percentage of slow-twitch muscle fibers, and therefore attain better results by training with about 12 to 16 repetitions per set. You should add 1 to 5 pounds more resistance whenever you complete 16 repetitions in good form. One set of each exercise is sufficient for strength development.

There is no reason to train with fast movement speeds, because training fast will not make you faster and training slow will not make you slower. Exercising with controlled movement speeds maximizes muscle tension and minimizes momentum for a better training effect. We recommend six-second repetitions, taking two seconds for each lifting movement and four seconds for each lowering movement.

Research supports three non-consecutive strength training sessions per week for best results, but fewer workouts can produce significant strength gains. Our recent studies have shown two weekly workouts to be 82 percent as effective and one weekly workout to be 69 percent as effective as three-day-per-week strength training.

Summary of Strength Training Guidelines

• Exercise all of the major muscle groups
• Perform 12 to 16 repetitions per set
• Add one to five pounds whenever 16 repetitions can be completed
• Perform one set of each exercise
• Use controlled movement speeds (six seconds per rep)
• Train one, two or three non-consecutive days per week

Recommended Strength Exercises For Runners
You may develop muscle strength with a variety of exercises using free-weights or machines. The following section presents recommended strength exercises for the major muscle groups.

Leg Muscles
Although barbell squats are the traditional leg exercise, most runners may do better to avoid placing a heavy barbell across their shoulders. Dumbbell squats are an acceptable alternative, but it may be difficult to hold enough weight to appropriately stress the large leg muscles.

Our recommendation is leg presses on a well-designed machine that offers a full movement range and good back support. It may be advisable to precede leg presses with leg extensions that target the quadriceps and leg curls that target the hamstrings. One set of each exercise is sufficient, but you may perform an additional set if you desire.

Upper Body Muscles
The typical exercises for the upper body are bench presses for the chest muscles, bent rows for the mid-upper back muscles, and overhead presses for the shoulder muscles. These are acceptable exercises, but are much safer when performed with dumbbells rather than barbells. For example, because there is no back support in a barbell bent row, the stress to the low-back area is 10 times the weight of the barbell. By using one dumbbell, and placing your other hand on a bench for back support, this exercise can be performed more safely and effectively.

If you have access to machines, we recommend chest crosses for the chest muscles, pullovers for the mid and upper back muscles, and lateral raises for the shoulder muscles. These machines require rotary movements that better isolate the target muscle groups. If you prefer linear movements that involve more muscle groups, well-designed chest press, seated row, and shoulder press machines provide combined training for the upper body and arm muscles.