For Runners, Soft Ground Can Be Hard on the Body

Hirofumi Tanaka, an exercise physiologist at the University of Texas at Austin, bristles when he sees dirt paths carved out of the grass along paved bicycling or running routes. The paths are created by runners who think softer ground protects them from injuries.

Dr. Tanaka, a runner, once tried it himself. He was recovering from a knee injury, and an orthopedist told him to stay away from hard surfaces, like asphalt roads, and run instead on softer surfaces, like grass or dirt. So he ran on a dirt path runners had beaten into the grass along an asphalt bike path.


The result? “I twisted my ankle and aggravated my injury while running on the softer and irregular surface,” he said.


In the aftermath of his accident, Dr. Tanaka said he could not find any scientific evidence that a softer surface is beneficial to runners, nor could other experts he asked. In fact, it makes just as much sense to reason that runners are more likely to get injured on soft surfaces, which often are irregular, than on smooth, hard ones, he said.


His experience makes me wonder. Is there a good reason why many runners think a soft surface is gentler on their feet and limbs? Or is this another example of a frequent error we all make, trusting what seems like common sense and never asking if the conventional wisdom is correct?


Perhaps a runner who, like me, strikes the ground with her forefoot instead of her heel, might risk more injuries on softer ground. After all, every time I push off on a soft surface, I twist my foot.


Exercise researchers say there are no rigorous gold-standard studies in which large numbers of people were assigned to run on soft or hard surfaces, then followed to compare injury rates.


There’s a good reason for that, said Stuart J. Warden, director of the Indiana Center for Translational Musculoskeletal Research at Indiana University. It’s too hard to recruit large numbers of people willing to be randomly assigned to one surface or another for their runs.


“I think the reason people haven’t answered that question is that it is not an easy question to answer,” Dr. Warden said.


When Dr. Willem van Mechelen, head of public and occupational health at VU University Medical Center in Amsterdam, searched for published studies on running injuries and how to prevent them, he, too, concluded that there were no good studies that directly support running on softer ground. “Significantly not associated with running injuries seem age, gender, body mass index, running hills, running on hard surfaces, participation in other sports, time of the year and time of the day,” Dr. van Mechelen concluded.


So what is going on? It seems obvious that the forces on your legs and feet are different depending on whether you run on soft packed dirt or on hard concrete. Why aren’t injury rates affected?


An answer that many accept comes from studies that addressed the question indirectly. In several of them, study subjects ran on plates that measured the force with which they struck the ground. Instead of varying the hardness of the ground, the researchers varied the cushioning of the shoes. More cushioning approximated running on softer ground.


Over and over again, studies like these found that the body automatically adjusts to different surfaces — at least, as mimicked by cushioning in shoes — to keep forces constant when foot strikes plate.


That finding makes sense, Dr. Warden said. If you jump from a table to the floor, you automatically bend your knees when you land. If you jump on a trampoline, you can keep your knees stiff when you land. Something similar happens when you run on different surfaces.


“If you run on a hard surface, your body decreases its stiffness,” Dr. Warden said. “Your knees and hips flex more. On a soft surface, your legs stiffen.” Running on a soft surface “is basically a different activity,” he said.


But those studies did not actually measure forces inside the body, Dr. van Mechelen noted. Instead, they used biomechanical modeling to estimate those forces.

“It is models, so God knows whether it is true,” Dr. van Mechelen said. “But to me it doesn’t seem far-fetched.”


Dr. Warden said some people adapt quicker than others to running surfaces, and he advised that anyone wanting to change from a soft to a hard surface, or vice versa, play it safe and make the change gradually.


Changing your running surface, Dr. Warden said, “is much like increasing your mileage, changing your shoes or some other aspect of your training program.” Abrupt changes can be risky.


But with no evidence that softer surfaces prevent injuries, there is no reason to run on softer ground unless you like to, Dr. Warden and other experts said. Dr. van Mechelen tells runners to get a pair of comfortable shoes and run on whatever surface they prefer.


Dr. van Mechelen, a runner himself, says his favorite surface is asphalt. Mine is too.


My coach, Tom Fleming, never suggested soft surfaces and never thought they prevented injuries. And, he said, there’s a good reason to run on asphalt, at least if you want to compete.


“Most road races are on hard roadways,” he told me. “So let’s get used to them.”


A version of this article appeared in print on July 19, 2011, on page D5 of the New York edition with the headline: For Runners, Soft Ground Can Be Hard on the Body..

Trail Running

By Leigh Brown Perkins
Her Sports + Fitness

When she trained for her third Tour du Mont Blanc ultra marathon last summer, Chlo Lanthier-Brandner never was spotted running the roads near her home in Whistler, British Columbia. She was always deep in the woods, blazing up and down old logging trails.

"All of my runs are on trails," Lanthier-Brandner says. "I forget I'm running."

Elite runners are not the only ones lured by trails. More than 5.7 million Americans consider themselves avid trail runners, an increase of 36 percent in the last five years, according to the Outdoor Industry Association. Another 37 million runners hit the trails a few times a year.
Nancy Hobbs, founder of the All-American Trail Running Association and co-author of The Ultimate Guide to Trail Running, explains the growing interest in trail running this way: "There's a real spiritual component to being on the trail. It provides a great physical challenge but in a serene, forgiving environment."

Trail running makes demands on a wider range of muscles than road running, without the repetition injuries of pounding pavement. Ankles, hips, inner and outer thighs and core muscles are engaged for balance. Trails more fully engage the quads, increasing leg strength. Taking on ascents and descents builds stamina, and difficult climbs sharpen mental focus.

Trail-Running Tips

Follow these tips for happy trails wherever you run.

1. Run tall. Running, especially uphill, can be exhausting, but if you bend under the effort it's more difficult for the lungs to do their thing. On the uphill, keep an eye at the crest or a few yards ahead, not at your feet. If you're gasping, slow down and pump your arms a little, or if you need to, walk, while keeping your posture tall. Even elite runners will walk a steep hill.


2. Shorten your stride on the way up. And plant your entire foot; climbing on your toes kills your calf muscles. Jump over obstacles. Stepping up on unsteady rocks and roots is not only tiring, it can be hazardous.

3. Be loose on the downhill. Stop braking and allow yourself to fly a little, throwing your arms to the side. But don't flail. If you lose control, slalom from side to side like a skier. Don't lean back or dig in your heels to brake (a guaranteed butt slide). Instead, land quickly and lightly.

4. Plot your moves. View the trail like a chessboard. Plan your steps around bumps, dips, soft sand and fallen trees yards before you reach them.

5. Focus on time, not distance. Don't expect to match your road PR. "Out-and-back routes are great because you can cover the same distance a little bit faster on the way back," Lanthier-Brandner says.

6. Diminish your risks. Run in pairs or let someone know where you're going and when you'll be back. Take plenty of fuel and fluid, a lightweight jacket and a cell phone, which won't always get a signal in the mountains, but might. Uphill runners yield to downhill runners. Yell "trail" well in advance of passing another runner or hiker.

7. Find your balance. Slippery downhills let you know what your legs are made of. Build them up between trail runs with weighted squats and lunges, and build your balance using wobble boards (check out www.performbetter.com for balance gear).

8. Keep your bearings. Things look different coming back than going. Pause to look around when two or more paths diverge from the one you're on. Look at trail signs and identify rocks, trees or landmarks on the horizon.
9. Leave no trace. Even in races, trail runners stow empty wrappers and wouldn't dream of dropping cups like road racers. Stay on marked trails, don't cut switchbacks and go through, not around, puddles to prevent erosion.

10. Feel like a kid again. Crank it on the downhill, hoot and holler, jump into a stream. "Trail running is a chance to get down and dirty, to grab hold of our authentic selves," says trail running coach and sports psychologist Terri Schneider. It'll make all those miles during freezing winters on the treadmill so worth it.

Trail Gear

Essential gear for a trail runner doesn't have to be anything fancier than a crusty pair of trail shoes, an old race tee and socks that will never be white again. But a few other purchases will get you running wild.

Shoes. Your favorite brand of road shoe won't necessarily manufacture a good trail runner, or a trail runner that works best for you. Trail running shoes sit lower than road shoes, with a harder midsole to take the impact of the trail. They provide greater ankle support to prevent rolling and more lateral support and flexibility for uneven terrain. They have sturdier, stickier treads. Runners who face stream-crossings or mud should wear trail shoes with drainage holes, waterproof uppers and laces that won't stretch when wet.

Apparel. Trail runners take layering seriously since weather at altitude can change instantly. When the temperature begins to cool, start layering with a running tank, then a long-sleeve tee, both made of a wicking fabric. A breathable, hooded jacket is vital. In warmer weather, stick with loose, wicking shorts. In cold weather opt for snag-proof tights.

Gloves. Wipeouts happen. Lightweight gloves protect hands from gravel burns, stray brambles and chilly air.

Socks. Find what works for you: wool blends, layered micro fiber, toe socks. If you blister, turn them inside out. Go with gray, brown or black.

Sunglasses. Since trails often lead from dark forests to brilliant glades, sunglasses make sense. Even on all-shade trails, glasses protect eyes from branches and clear lenses keep debris from contacts. Lanthier-Brandner recommends orange lenses, which work well in all light, or shades with interchangeable lenses.

Hydro packs. Dehydration happens quickly at altitude so carry water. Hydration packs are necessary for longer runs; bottle belts for shorter trails. Buy packs that are sized for women, with lots of pockets to stash energy gels, bars and a cell phone.

How to Reduce Your Added Sugar Intake

from the Nutrition Diva

by Monica Reinagel, M.S., L.D./N.

A few weeks ago, I wrote an article explaining how eating too much sugar affects your body. As a guideline, I suggested trying to limit your intake of added sugar to 50 grams a day. Since then, I’ve got a lot of questions from readers about how to implement this guideline. So, today, a follow-up to my original article, with answers to your questions about limiting added sugars.

Why Should You Limit Added Sugar?

As I explained in my original article, although a little bit of sugar is OK for most people, eating too much sugar can undermine your health in a lot of ways. Sugar can add excess calories to your diet, crowd out more nutritious foods, and otherwise contribute to aging, weight gain, and disease.

How Much Sugar is Too Much?

The World Health Organization recommends that you limit your intake of added sugar to 50 grams a day, and this was the guideline that I mentioned in my original article. For the average adult, fifty grams of sugar works out to about 10% of their total calorie intake.

Some people would set that limit a lot lower—in fact, the American Heart Association recommends just 25 grams of added sugar a day.

Of course, you could try to eliminate 100% of the added sugar from your diet. But that strikes me as unnecessarily austere. If you’re basically healthy and you have a reasonably nutritious diet and active lifestyle, I don’t think a zero tolerance policy is necessary.

Honestly, because so many of today’s health problems stem directly from excess sugar consumption, I think any reduction would be a step in the right direction. And because the typical American is currently consuming about 100 grams of added sugar a day, cutting that intake in half seems like a good place to start. 

What Counts as an “Added Sugar”?

Whether your goal is to eat only 25 grams of added sugar a day or 50, you need to know what counts as an “added sugar.” You’ll be relieved to know that the sugar in fruit is not considered to be an added sugar. Fruit is relatively high in sugar, of course, but also contains other desirable nutrients. And although it is possible to consume an excessive amount of sugar by eating lots and lots of fruit, this is generally not where the problem lies for most people.

To keep your diet in balance, aim for two to four servings of fruit a day, preferably whole, fresh fruit rather than juice. But you don’t have to count the sugar in fruit toward your added sugar total.   You also don’t have to count the naturally occurring sugars found in dairy products like milk or unsweetened yogurt.

Here’s what does count: Any sugar that you use in your own cooking or add at the table, plus any sugar in processed or prepared foods or beverages counts as an added sugar.

Do Natural Sugars Count as Added Sugar?

When counting added sugars, no distinction is made between “natural” sugars like maple syrup, honey, agave nectar, or fruit juice concentrate, and refined sugar or high fructose corn syrup. All concentrated sweeteners are counted as added sugar, regardless of whether they are liquid or granular, organic, raw, natural, or refined.   That doesn’t mean that natural or organic sugars don’t offer any advantages. It just means that you don’t get to consume more of them just because they are natural.

How to Reduce Your Added Sugar Intake

The next step is to figure out where all that added sugar is coming from.   According to the American Cancer Society, almost half of the sugar in the typical diet comes from sweetened beverages. That would include soda and other soft drinks, sweetened teas and juice drinks, and sport drinks like Gatorade (although it wouldn’t include artificially sweetened beverages).

Another quarter of the added sugar in the typical diet comes from sweet treats like candy, cookies, cakes, ice cream, and sweetened breakfast cereal. And the remaining 25% or so of the sugar in our diet comes from the sugar that we use in cooking, add at the table, or stir into our coffee, plus all the sugar that’s hidden in processed and packaged foods like crackers, salad dressings, spaghetti sauce, and just about everything else.

How to Spot Added Sugar in Packaged Foods

Trading that afternoon cola for an unsweetened iced tea could cut 50 grams of added sugar out of your diet in a single swipe!

To see how much sugar is in packaged foods and beverages, take a look at the Nutrition Facts label, which tells you how many grams of sugar is in each serving. For most foods, all of the sugar on the label is “added sugar.” Quick and Dirty Tip: Be sure to check how many servings are in the package. Often a package that seems like a single serving actually contains two or three servings. If you eat or drink the whole thing, you’d need to multiply the grams of sugar per serving by the number of servings you consume.

Sometimes, however, the sugar listed on the Nutrition Facts label is a combination of added sugar and natural sugar from fruit or milk—and that can be a little trickier to calculate.   You may have to do a little sleuthing around. For example, an 8-ounce carton of low-fat milk contains 12 grams of sugar. That’s all naturally occurring milk sugar (or lactose) and you wouldn’t have to count that toward your added sugar limit. An 8-ounce container of chocolate milk, on the other hand, contains 30 grams of sugar. If 12 grams of that are accounted for by lactose, you can estimate that the remaining 18 grams is added sugar.

Likewise, you can compare a jar of unsweetened applesauce with a jar of sweetened applesauce to see how much of the sugar is added and how much is natural sugar from the apples. Unless a product contains a substantial amount of whole fruit or dairy, however, I’d count all of the sugar in a packaged food as added sugar.

How Much Sugar Are You Eating?

Why not spend a couple of days tracking your added sugar intake? Check the labels of all packaged foods that you eat. Don’t worry about the naturally occurring sugar in fresh fruit or unsweetened dairy products but make sure to count any sugar that you put in your coffee or honey that you drizzle over your oatmeal. If you eat out, you can often get detailed nutrition information on restaurant websites or on websites like nutritiondata.com.

If you’re taking in more sugar than you mean to—or want to—take a look at where the sugar in your diet comes from and you might see some obvious ways to cut back. For example, just trading that afternoon cola for an unsweetened iced tea could cut 50 grams of added sugar out of your diet in a single swipe! (And for a reminder of why you might want to, see my article, “How Sugar Affects Your Body”)

Why Do You Feel Like Puking During Races?

Updated: Jul 26th 2011 by Matt Fitzgerald


A new study suggests carbs are not the main culprit.


Written by: Matt Fitzgerald


Symptoms of gastrointestinal distress, including nausea and flatulence, are relatively common during endurance races such as marathons and Ironman triathlons. Athletes commonly assume that GI distress is caused by overconsumption of carbohydrate (sports drinks, gels, and so forth). However, a new study published in the journal Medicine & Science in Sports & Exercise suggests that this is not the case.


Researchers at four European universities recruited 221 athletes who participated collectively in two Ironman triathlons, one Ironman 70.3 event, a long cycling time trial, a cycling stage race, and a marathon and invited them to fill out questionnaires after completing their events. The athletes were asked to recall their nutrition intake during their individual races and rate the severity of 12 different symptoms of GI distress on a 0-9 scale.


Analyzing the data on nutrition intake, the researchers determined the average rate of carbohydrate intake in each type of race. Triathletes consumed the most carbs, at rates of 62 to 71 grams per hour in the three races included. Cyclists consumed somewhat less carbohydrate (53 g/h), while marathon runners took in the least—just 35 g/h.


Serious GI symptoms were reported in 31 percent of Ironman triathletes, 14 percent of Ironman 70.3 racers, 7 percent of cycling stage-race participants, 4 percent of cycling time-trial competitors, and 4 percent of marathoners. As you can see, there was a clear correlation between the average rate of carbohydrate intake in each type of race and the risk of serious GI symptoms.


Before we blame race GI problems entirely on overconsumption of carbohydrate, however, we need to dig a little deeper. If carbs were truly the main culprit then we would expect to see that, within each type of race, those athletes who consumed the most carbs had the highest risk for GI distress. But this association was not seen in runners, cyclists, or Ironman 70.3 racers. Only Ironman racers faced a greater risk of GI distress when they consumed more carbs.


It also bears noting that the rate of serious GI symptoms was more than twice as high in Ironman racers than in Ironman 70.3 competitors despite the fact that the rates of carbohydrate intake were the same. It’s interesting as well that the rates of GI distress were the same in marathon runners and cycling stage racers despite the fact that the cyclists consumed 50 percent more carbs, on average.


These numbers suggest that the particular nature of the race contributes to the risk of GI distress more than the rate of carbohydrate intake does. It seems likely that the risk of GI distress in the two Ironman events was more than two times greater than in any other race simply because it lasted twice as long as any other race for most participants. I think you’d find that the risk of all kinds of things—heat illness, bonking, etc.—was more than two times greater in the Ironman. It’s just more stressful all around.


Yet the incidence of GI distress in an Ironman 70.3 was twice as high as the risk in a cycling stage race despite taking no longer to complete. This tells us that not only the length of a race but also the transition from cycling to running contributes to the risk of GI distress. It would be very interesting to know exactly when symptoms of GI distress most commonly appeared in the triathlons studied. I’d be willing to bet it was within the first 10K of the marathon start.


There’s a reason the runners in this study reported consuming only 35 grams of carbohydrate per hour while racing a marathon, whereas cyclists reported taking in 53 g/h. The GI system cannot tolerate as much nutrition consumption during running as it can on the bike. In triathlons, racers commonly consume carbs at a rate that is tolerable on the bike, only to find that the amount or concentration of calories in their guts becomes intolerable once they start running.


Besides the particular nature of the stress that a given type of race doles out, there is another factor that also appears to be more important than the rate of carb intake in relation to the risk of GI distress: past history of such problems. The researchers found that the correlation between past GI problems in races and GI problems in the races included in this study was stronger than the correlation between the rate of carbohydrate intake in the studied races and GI distress. In other words, athletes with a history of GI problems tended to have GI problems in these races even at lower levels of carb intake, while those without such histories tended not to have problems even at higher rates of carb intake.


A final note: Even though higher rates of carb intake were linked to higher risk of GI issues in Ironman races, those athletes who consumed the most carbs also tended to finish the race faster! Just because you experience some nausea and flatulence during an Ironman does not automatically mean your race is ruined. More often than not, these things are just a price you pay for doing an Ironman and for taking in enough fuel to finish with the quickest time possible–and they’re a price worth paying.


About the Author:
Matt Fitzgerald is a senior editor at Competitor Group, with regular contributions to competitor.com, Triathlete, Inside Triathlon and Competitor. Matt has written 17 books, and counting, including Brain Training For Runners and Racing Weight.