When Chris Clark, a little-known Alaskan runner, won the 2000 U.S. Women’s Olympic Marathon trials, she took the running world by storm. Within minutes of her victory, writers churned out stories about her 70-mile training weeks done exclusively on her basement treadmill. While the debate about treadmill running versus road running started in the 1950s, Clark’s victory put it back on the front page. Although some runners view treadmill running like the plague, others enjoy its convenience and safety. Regardless of personal preference and scientific differences, both treadmill running and road running benefit runners and boost cardiovascular fitness.
Benefits of Treadmill Running
Treadmill running benefits runners in several key ways. When snow swallows your favorite running path or when a heat wave crashes in, the treadmill works as a great alternative by making weather conditions irrelevant. Whether you head to the basement or to the local gym, treadmill running offers a safe and convenient training environment. For injury-prone runners, the smooth surface and extra shock absorption significantly reduce pounding and stress on the joints. Treadmill running also teaches runners the value of consistent pacing and forces them to remain mentally sharp as they fight through muscle fatigue in order to maintain training speed. In the same way, it teaches them to run easy on recovery days--if you set the pace and stick to it, you reduce the temptation to run too hard.
Benefits of Road Running
Road running jibes with the fundamental training principle of “specificity”--meaning your everyday training matches your training goals. If you plan on running a spring marathon or a fall cross-country race, you should run the majority of your miles outdoors. Road running compels you to adapt to shifting terrain, changing scenery, weather patterns and wind resistance. Because of the varying terrain and the ground contact, road running burns more calories and demands more energy from your leg muscles.
Wind Resistance and Oxygen Consumption
Many runners believe road running presents more challenges than treadmill running, and the scientific evidence explains why. Running outside forces runners to contend with the wind and to expend more energy as a result. Wind resistance alone increases a runner’s workload 2 to 10 percent; the faster you run, the more resistance you feel. Although indoor runners can compensate for wind resistance by setting the treadmill to a 1 percent incline, they cannot compensate for shifting terrain or changing scenery. In addition, road running causes runners to consume more oxygen (largely due to wind resistance and changing terrain), making outdoor running slightly more difficult than treadmill running.
Conflicting data over the precise biomechanical differences between treadmill and road running keeps the debate alive, but the data shows that differences do exist. Depending on a runner’s experience, stride length either increases or decreases on the treadmill compared to road running. One study showed more experienced runners increased their stride lengths while newer runners shortened their strides. Meanwhile, runners almost universally experience increased “support time” on the treadmill. Support time refers to the amount of time the support leg spends on the ground. The most economical runners keep this support time to a minimum to maximize efficiency. However, running on a moving belt increases support time because the legs must constantly reposition and stabilize the body. Along these lines, treadmill running may alter your running form. Some runners lean forward less on the treadmill than outdoors, and some unconsciously change their arm swing.
Psychological considerations depend on the individual runner. Some runners cannot tolerate running “in place” on a treadmill. They crave the psychological cues of progress: passing other runners, rolling over different surfaces and hitting specific landmarks. These runners generally embrace fighting through adverse weather conditions. Others simply view road running as the purest form of the sport. Of course, some runners focus better on the treadmill and measure progress with every mile they click off; they enjoy the safety, convenience and mental challenge of treadmill running.