You're going along fine on a level surface,
running your heart out,
maintaining a stellar pace,
and generally feeling pretty great about your performance.
Then you reach a hill.
You trained for this by increasing the incline on the treadmill.
You crest the hill with a little less breath, but still feeling good.
You start downhill,
anticipating a chance to regain your breath and your speed,
but suddenly there's a hitch in your gait and panic sets in.
Why are you experiencing soreness and pain on what should be the easiest portion of your run?
Going downhill should be a breeze, but your pace is slowing as you try to ease up.
What the heck happened?
Runners are no stranger to aches and pains, and while running downhill definitely gives your cardiopulmonary system a break, it can place a lot of strain on your body as you try to maintain speed while also remaining upright.
This particular form of strain is known as eccentric loading, and it happens because muscle signals are at odds.
Your muscles have to stretch to reach the receding ground, but at the same time, they're trying to contract to combat the increased impact of added gravitational force.
The result is a number of aches and pains running down your legs.
What causes this soreness and what can you do to combat it?
It's no surprise that joint pain increases when running downhill.
You're basically falling and catching yourself with every step, and this creates a huge force of impact on your knee joints each time your foot hits the ground.
This happens when you run on a flat surface, too, but to a lesser extent. The good news is that your muscles will compensate to absorb much of the shock, but your joints could still feel significant soreness if you're not used to downhill running.
The real damage of running downhill is mainly to your quadriceps, which compensate the most, just as your calves and hamstrings are likely to feel the burn on the way up the hill.
When your foot makes impact with the ground, the force travels up your leg, impacting your knees. If not for the reaction of your muscles, this force would cause your joints to buckle.
Fortunately, however, your quads contract in response to the added impact, pulling up to protect your knees. The juxtaposition of your quad muscles simultaneously trying to stretch and contract is the source of eccentric loading, and also the soreness and even pain you experience as a result.
There is a silver lining, however, and it's called practice. Any time you know you're going into a race with significant downhill segments, you need to prepare by practicing hill runs leading up to race day.
It's going to hurt at first, and maybe quite a bit. The good news is that you'll heal up and your legs will come out stronger and better prepared to face hills in the future. You don't want to overdo it and really damage yourself, though, so intersperse hill runs with your regular running routine to strengthen quads and protect knee joints.
This doesn't technically qualify as soreness, so much as fatigue, and often, runners experience it equally running uphill, downhill, or on flat stretches. However, heavy or dead-feeling legs can definitely pose a problem. It tends to be caused by over-training.
There's not a lot you can do on race day if you discover your legs feel heavy and unable to perform to your usual standards.
If this is a frequent occurrence, however, you have options. While you can spend a few days in rest and recovery, you're going to suffer a setback and have to regain ground afterward.
A better solution is to switch to aerobic running. Take a break from your grueling hill-training schedule to go for a jog.
That's right, a laid-back jog around your neighborhood or your favorite running trail. Stay away from the strenuous and instead focus on warming the muscles and oxygenating the body.
Think of it as active recovery.
This allows your body to rest and recuperate without losing any ground, and if one aerobic run doesn't do the trick, substitute in 2 or 3 for your regular training.
This should be enough for your body to recover, reset, and return to your regularly scheduled training, at peak performance levels.