Three words describe every one of REVEL’s marathon and half-marathon courses:

• FAST
• BEAUTIFUL
• DOWNHILL

Downhill running, especially FAST downhill running, can subject runners to higher stresses on the legs due to eccentric force, which is a major cause of delayed-onset muscle soreness, or "DOMS."

But with proper form and proper training, runners can curb the effects of eccentric force, and in turn lessen the severity of DOMS.

Sore legs are common for distance runners for a period of 1-3 days after a race. The pain, soreness, tenderness, loss of strength, and reduced range of motion are all familiar to runners after completing a marathon or half marathon.

Many runners will tell you that the worst soreness is not the day of, or even the day after a race, but is 2-3 days after the race. The culprit? Delayed-onset muscle soreness, or DOMS.

The common misconception that DOMS is caused by "lactic acid in the muscles" is completely wrong. DOMS in the leg muscles is caused by eccentric force, where the muscles are doing two things at once: (1) acting like “shock absorbers” to absorb the impact forces of landing on your foot, while at the same time (2) lengthening like a spring to propel the body forward. The end result is that the muscles are pulled in two different directions at the same time, which results in microscopic tearing of the muscle fibers. The muscle damage triggers an inflammatory response by the body, resulting in swelling, stiffness, and tenderness in the muscles. The good news is that most of the symptoms of DOMS, which fade in a few days, are a result of the body’s inflammatory response, not damage to the muscles themselves.

Eccentric force occurs while running on any surface, but it is much greater when running downhill. Some research indicates that the impact forces of running increase by more than 50% when running downhill, while the braking forces of every foot strike can increase by up to 75%. The reason is simple: the body’s momentum, added to the force of the body moving downward, dramatically increases on a downhill surface. Consequently, the leg muscles - especially the quadriceps – are subjected to repeated and high levels of eccentric force as they lengthen with every foot strike, while at the same time shorten as they absorb the impact.

For runners who are not accustomed to downhill running, the higher levels of eccentric force in a downhill race can cause two major issues: early fatigue in the race; and higher DOMS effects after the race.

First, the increased strain on the major running muscles can cause those muscles to fatigue more quickly in the race. The benefit of the downhill course – gravity – ultimately can become a liability for a runner who is not prepared for downhill racing. Instead of running fast and efficiently in the latter miles of the race, the unprepared runner is struggling with worn out muscles.

Second, the added stress from running downhill can dramatically increase the effects of DOMS typically associated with running marathons and half-marathons. Instead of a “normal” recovery time post-race, the ill-prepared runner might need a few more weeks of recovery after a hard downhill race.

But this does not mean that downhill races have to “hurt more” than any other races, or that downhill racing has to be intimidating for anyone. With proper training, and proper downhill running form in the race, all runners can take advantage of a favorable downhill course profile and experience remarkably fast results, lower the effects from DOMS, and resume running after normal recovery times.

The best way to reduce the effects of increased eccentric force in a downhill race is to train using what is known as “repeated bout effect.” This training effect occurs when a session of running downhill in a workout (a “bout”) provides a protective effect in subsequent workouts of the same nature. After recovering from normal muscle damage and soreness from a downhill session, runners can recover faster, and experience less DOMS, after subsequent workouts.

This doesn’t mean that the best way to build “downhill running ability” is to go out for a couple of downhill runs a few weeks before your race. The “repeated bout effect” regimen should follow a measured and meaningful schedule that allows time to recover and adapt from one session before the next one. Moreover, the intensity of the downhill workouts should be very light in the early sessions, and with short distances. Over time, the intensity and distance gradually increase. Meanwhile, ensuing workouts should take into consideration the need for short recovery from the downhill intensity. Your body will need a little extra time for the inflammation and repair process to take place before you attempt any other type of intensity in a “hard” run.

All totaled, a proper training schedule for a downhill race should incorporate two major elements to maximize the gains from a downhill course, while minimizing the effects of eccentric force: (1) repeated bout effect sessions over a number of weeks, with gradually increasing intensity and distance; and (2) regular practice of using proper downhill form. With both of these training elements in your training regimen, you should be well prepared for any downhill race.