In the late 1980s the coach of a high school women's cross-country and track team agreed to bring his runners to our Nautilus facility during the off-seasons for supervised strength exercise. They trained three days per week, performing one set of 12 different exercises that addressed all of their major muscle groups. This well-disciplined group of about 25 women moved quickly between the machines and completed the strength training circuit in about 25 minutes.
I would like to say that the strength exercise was responsible for the four consecutive New England cross-country championships won by George Rose's harriers. I cannot draw that conclusion, but I can certainly state that the strength training did not hurt. In fact, I believe that the strength training was effective for preventing a lot of hurts normally experienced by distance runners. During the four years they did the strength exercises, the cross-country runners had only one injury. There were no shin splints, stress fractures, knee problems or hip injuries, so common among women distance runners. The one injury was a broken ankle that occurred when a runner stepped in a hole on a poorly groomed course.
The point of this true story is that strength exercise may not directly improve running ability, but it may greatly reduce injury potential thereby enabling athletes to run more consistently. In fact, we observed similar results with two other cross-country and track teams in the years following.
Unfortunately as the coaches moved on, these successful strength training programs were largely discontinued. Sad to say, many distance coaches and runners have the mistaken impression that strength exercise is counter-productive for better running. When questioned further, many indicate that strength training will increase bodyweight, decrease flexibility and interfere with running form.
Fortunately, most successful distance runners have ectomorphic physiques that resist gains in bodyweight. The two to four pounds of muscle that may be added through strength training is like putting more cylinders in your automobile engine. That is, the overall weight gain is minor, but the greater power output is highly desirable.
With respect to joint flexibility, no studies have shown sensible strength training to decrease range of motion, and several have demonstrated significant improvements in movement parameters. This is especially true when you combine strength training with stretching exercises. For example, in one of our research studies with adult athletes, a combined strengthening and stretching program resulted in a four-pound muscle gain, a three-pound fat loss, a 56 percent increase in muscle strength, and a 24 percent increase in joint flexibility 1. By the way, the subjects' movement speed in the selected performance skill increased by six percent.
But what about running form? Just look at sprinters and shorter distance runners. Most of these athletes strength train regularly and their times keep getting faster and faster. Running speed is the interaction of stride length and stride rate, and strength training appears to be advantageous for both of these abilities.
During the latter stages of a race when your leg muscles are fatigued and your arm action keeps you moving, the benefits of more upper body strength may be better appreciated. Another aspect of cross-country and road running where greater strength makes a difference is hills, both up and down. Obviously, stronger muscles provide more power for running up inclines. Just as important, they also offer better shock absorption, and therefore more injury protection, when running down declines.