When Kyra Oliver heads out for her morning run, she usually opts for a paved route. But once or twice a week, the San Diegan heads toward the beach instead, where she watches the sun rise and listens to the waves crash as the miles tick by. Running on the sand helps Oliver clear her mind, but it also supplements her training for marathons and 50-mile trail races.
“It works different muscles and requires a different focus for me,” Oliver tells Runner’s World. “If I’m on the packed sand by the water, I can set a nice pace and do short pickups. Running where [the sand is] looser can be a good strength workout that simulates variances I might find on the trail.”
Oliver’s right: Opting for a soft surface like sand is a smart way to add diversity to your regular training routine. “By putting in mileage on the sand, you’ll put less stress on your weight-bearing joints, such as your hips, knees, and ankles, which can help decrease the risk of impact-associated injuries like stress fractures,” says Erika Lee Sperl, a kinesiologist and high-performance sport consultant for Orreco, a sports and data analytics company in Los Angeles that helps elite athletes optimize performance.
Research backs that up. Studies have shown that running on the beach, especially on soft, dry sand that’s typically found farther from the water’s edge will likely lower your odds of impact-associated overuse injuries. In a small 2017 study published in the European Journal of Sport Science, for example, women who ran on soft sand experienced less muscle damage and inflammation than those who ran on grass. And a 2014 study published in the Journal of Sports Sciences found that the soft surface even reduced muscle soreness and fatigue.
“With every foot strike, there is almost four times less impact force on soft sand versus firm ground like grass,” says Martyn Binnie, Ph.D., a physiologist at the Western Australian Institute of Sport and coauthor of the latter study. “This is a good thing for reducing load through the body.”
Sand is a great option when you need a lower-impact session but still want a hard workout. But there’s a flip side to every coin; while running on soft sand makes you less likely to suffer an impact injury, the chances of other injuries (like a sprained ankle or tendinopathy) rise, says Armin Tehrany, M.D., an orthopedic surgeon and founder of Manhattan Orthopedic Care in New York City. An uneven surface and constantly shifting ground are to blame, he explains, but as long as you exercise caution, those are two factors that can also enhance your workout.
“You’ll have to work harder [to stay balanced], and as a result, you will get a better workout if you spend the same amount of time on sand,” he says.
In fact, a 2013 study published in the Journal of Strength and Conditioning Research found that running on sand forces your body to work at least 10 percent harder than it does on grass. Again, soft, loose sand is where you’ll score the most benefits, says Binnie, who conducted the study, but even firm, packed-down sand can boost your performance.
“Firm sand near the water is still about 5 to 10 percent softer than grass,” he explains.“[But] if you want the big benefits, you need to aim for the soft stuff.”
So what exactly makes sand so special? When you run on firm ground, Binnie says, less elastic energy, which is stored in your tendons, is absorbed, so you don’t have to work quite as hard. Sand doesn’t extend that courtesy. Instead, it absorbs that energy, meaning you have to generate more force with your muscles. Proof: A study published in The Journal of Experimental Biology found that running on sand actually requires 1.6 times as much energy expenditure as running on a firmer surface.
Couple that with the fact that your hip- and knee-stabilizing muscles are working nearly twice as hard, according to a study published in the European Journal of Applied Physiology, and you’ve got a recipe for a higher heart rate and blood lactate threshold, says Binnie. Translation: Your cardiovascular training gets a boost without the added stress of having to run faster or farther. Those aren’t the only benefits you’ll gain, either.
“Running, especially on the road or a treadmill, is a very uni-planar, repetitive exercise, which can lead to muscular imbalances. Often the common weakest links for runners are the glutes, hamstrings, hips, and ankles,” Sperl says. “By running on sand and challenging your stability, you’ll start to build strength in these areas, which can carry over to performance benefits on the road.”
Binnie notes that because of the different technique and range of motion used on sand to combat the “slip” element, the joint angles around the hip, knee, and ankle are similar to those normally seen during faster running speeds on firm ground. So, theoretically, he says that if you wanted to improve your road running time, then incorporating sand running into your training, specifically early in the season, can help augment training adaptations. That’s why each expert suggests adding a sand run into your routine on a regular basis if you have access. If not, take your runs to the beach on vacation.
You should, of course, be smart about it. Ease into any new training technique slowly to minimize soreness and reduce injury risk. Always warm up and focus on the posterior chain (calves, hammies, glutes), which is activated more on the sand, Sperl says. Go slower than you think you have to. Sand is harder to run on, so Binnie suggests giving your body two weeks to adjust before increasing time and intensity. Tehrany suggests also aiming for time, not distance. That way, you’ll net a more challenging workout in the same number of minutes than you would on pavement. And always focus on your form. Sperl points out that the instability of sand will force you to shift forward naturally.
To go barefoot or not is a big question, and Sperl says the answer is often based on preference and where you’re running. When staying close to the water, most runners wear shoes to protect their feet from crushed seashells or small rocks, while those in softer areas usually go barefoot so sand doesn’t fill their shoes.
But Tehrany says to think twice before ditching your shoes. Keeping them on makes an ankle and foot injury less likely because the shoes act as an ankle stabilizer and provide elevated heel and arch support that your feet are used to, he explains. How often you hit the sand—and in which way—depends on your personal fitness and goals. Sperl, for example, turns to sand for added resistance during short interval speed sessions, whereas Binnie suggests doing long, slow runs on the beach when you’re not gearing up for a road race.
“The greatest difference in energy cost between sand and firm surfaces occurs at slower running speeds, as you spend more time in contact with the surface during foot strike,” he explains.
So while doing those slower runs on the sand means you’re likely not moving any faster, you’ll be getting a better overall workout. And what runner doesn’t want that?
Tips for Beach Running
Check the Tides: A low tide creates the most level, hard-packed surface for running. As the water ebbs, it leaves hardening sand behind that’s still forgiving—similar to a soft trail—underfoot. Ideally, you want to run at the lowest tide of the day, or an hour or two around the lowest point, and stay close to the water’s edge without getting your feet wet. In beach communities, local newspapers print high and low tide times each day, and there are a couple online resources for tide charts, such as the one found here: tidesandcurrents.noaa.gov.
Check Your Knees: Some beaches have more slanted surfaces than others, but even the most level beaches, at the lowest tides, have some slant to them. And generally speaking, the higher the tide, the more angled the sand. Running on an angled surface can wreak havoc on your knees and hips. Make sure you run both directions on the beach, to allow both legs to manage the unevenness. If you feel any knee or hip pain, stick to the roads or level trails.
Gear Up: Sunscreen is a must, to protect yourself from the reflective rays coming off the water as well as the rays from directly overhead. Sunglasses and a hat or visor are also helpful in keeping you comfortable and focused on your run. Since it’s sometimes inevitable that sand will get in your shoes, wear socks that ward off blisters. If your sock and shoe combo still isn’t abating the rub, consider a lubricant like Sportslick or BodyGlide for long runs, especially long runs where your feet might get wet and sandy.
Get a Workout in the Deep Sand: Even if you can’t get down to the beach at low tide for the hard-packed sand, running in deep sand once in a while is a great kick in the butt. Sand, like soft snow, gives with every step, so your leg muscles will feel the burn.
Take Advantage of Where you Are: Nothing caps off a great beach run better than a jump in the ocean (and thank goodness for quick-dry gear). A soak in the sea won’t give you the same recovery benefits as an ice bath—unless you’re running on a beach in Maine in the winter—but it will undoubtedly leave you refreshed.
[Originally reported by Runner’s World.]