Have you ever heard that running on a flat treadmill is like running downhill? Here’s why: When we’re airborne in midstride, neither foot is in contact with the treadmill—no problem there. But as soon as the leading foot makes contact, the backward motion of the treadmill grabs the heel and—more quickly than road running—draws the forefoot onto the belt. This accelerated motion actually mimics running slightly downhill. It requires a higher level of anterior shin muscle strength, which is why many people get shin splints on treadmills (an easy way to avoid this is to increase the incline a few degrees). Read on to learn more about how treadmills can affect your stride.
A few other treadmill truths:
1. Treadmill running pulls on the hip flexors at a predetermined belt speed and, through a neurologic “stretch reflex,” the flexors are activated at the same time. This inhibits the hip extensors (glutes), making it more difficult to fire them.
2. With the backward belt motion, the knee is drawn into extension more than in road running, mildly stretching the hamstrings. That same “stretch reflex” will inhibit and weaken the quadriceps.
3. The moving belt has a tendency to encourage more ankle dorsiflexion. This promotes a heel strike and initiates a stretch reflex in the calf, increasing risk for Achilles injuries, calf shortness and other biomechanical faults.
4. The treadmill naturally draws the leg backward, as opposed to the gluteal muscles doing this job, and causes a faster forward swing on the recovering leg. (Want to feel this effect? Speed up your treadmill.) This can cause more hip flexor recruitment, which can again inhibit proper gluteal function. If your core isn’t sufficiently engaged, these overactive hip flexors will draw the pelvis forward, increasing the arch in your spine. Can you say back pain?
Use treadmills with awareness, and find a speed and incline where you feel as though you are slightly pushing the belt backward instead of the belt pulling you backward. This may be enough to stay healthy and injury-free.
The Gait Guys are Drs. Shawn Allen and Ivo Waerlop (Thegaitguys.com).