May 4, 2023

Pooping for performance (Yes, there’s a scientific study)

This article falls into one of my favorite categories: “Didn’t see it coming.” Also: “I knew it felt good, I but didn’t know why.”

Researchers tested a group of elite triathletes after “rectal defecation” (pooping) vs no rectal defecation. A good poop decreased systolic blood pressure, increased blood supply in the prefrontal brain, and increased “sub navel oxygen consumption” (oxygen pickup of the leg muscles, a good thing.) Most importantly: “Pre-exercise defecation significantly improved high-intensity endurance performance.”

Conclusion: “This study demonstrated a performance enhancing effect of defecation for elite triathletes.” I think race directors might have to increase their Porta Potty orders. More at J of the International Society of Sports Nutrition (free full text).

Do super shoes change the 180 strides/minute rule?

There’s a modest history of researchers counting stride rates here and there--at elite road races, elite track races, and among recreational marathon runners. They often evaluate footstrike at the same time--forefoot vs midfoot vs rearfoot--although they don’t always use the same definition of these three.

But the running world has turned upside down since the last of these studies was performed. Now everyone’s wearing super shoes. So how does that change things?

To find out, a Spanish team measured foot strike and cadence of runners in the Tokyo Men’s Olympic Marathon in the summer of 2021. About 69% of the runners used a midfoot strike, while 31% landed on their rearfoot, and only 10% on the forefoot.

The low forefoot result made sense to the investigators as they termed it “the most demanding landing technique,” thus not preferable for 26.2 miles. “We can conclude that midfoot striking is the most favorable technique for long distance road events.”

They found that the average stride frequency of the top 8 finishers was 185/minute, while the three medalists averaged 188/min. These results were largely similar to previous study outcomes. Impressively, the Olympic runners maintained their stride frequency across the full marathon distance.

The study provided specific reference to Eliud Kipchoge’s stride rate. Kipchoge ran the second half of the Olympic Marathon about 2 minutes faster than the first half, but he barely changed stride rate at all. Therefore, he got faster by increasing his stride length. In the beginning, middle, and end of the marathon, his stride rate per minute was: 186, 185, 187. More at PrePrints.org (free full text).

How an expert carbo loads: Bagels, bagels, bagels; then graham crackers

Marathon runner and sports nutritionist Meghann Featherstone ran a personal record on the Boston course several weeks ago in her fourth effort there. Here’s how she carbo loaded beforehand, presented in such exhausting detail that you’ll be glad you don’t have to run a marathon after reading her story.

But you might also be convinced to redouble your nutritional focus before your next marathon. More at Featherstone Nutrition.

A hot debate: Should every runner try the marathon?

Here’s an intriguing question that many runners have found themselves facing. The Forum questioner says he/she is happy and healthy running half marathons. But of course it’s impossible not to think about the marathon distance. Is the full 26.2 worth trying? 

Some respondents argue, essentially: If it ain’t broke, don’t fix it. That is, if you’re happy doing what you're doing (nothing longer than a half marathon), there’s no reason to change your habit. Makes sense, right? Hard to argue against this perspective.

Of course, some do. And I like what they say: “Marathons aren’t the only game in town, but I can tell you they are very rewarding, and bring something different to the table.” Also: “You should definitely continue to do things in running that scare you a little or that you’re uncomfortable with.” 

This is one reason ultra running has grown so popular. Many runners are curious, adventurous, and willing to explore the unknown and challenge themselves--all excellent qualities. More at Reddit/Advanced Running.

 

3 ways to strengthen tendons and ligaments

All runners are worried about Achilles tendon injuries, because you can’t go far or fast without a healthy Achilles. Other lower leg tendons are also important: the iliotibial band, the patella tendon, the tendons up high on your hamstring, and down low (peroneal) in your foot.

This article discusses three ways to strengthen these tendons, making them more resistant to injury: with eccentric exercises, plyometrics, and isometric contractions. I had never thought much of using isometric work to begin an injury-recovery plan. Sounds smart. 

Once you feel your muscle has regained good health, you can move on to plyometrics and eccentric strength training. Both have the potential to actually improve performance. More at Training Peaks.

Drink these 3 fluids to live longer

What are the best fluids to drink on a daily basis when you’re not exercising? The author of a big new study has a direct answer for that. “Based on our study I would rank black coffee, unsweetened tea and plain water higher than low-fat milk, fruit juice or artificially sweetened beverages,” he told CNN.“Sugar-sweetened beverages like colas, fruit juices that are high in sugar and whole fat milk that’s high in saturated fat are known risk factors for developing type 2 diabetes and premature cardiovascular disease.”

Of course, you’ll need sugar in your beverages when running, especially marathon-like distances. When you exercise, the body’s biochemistry changes in dramatic ways, and that which is bad while you’re watching TV--sugar--suddenly becomes an essential ingredient that fuels performance.

In the paper behind the CNN report, researchers followed more than 15,000 adults with diabetes for 18.5 years to see how their beverage-consumption affected their development of heart disease and death rates. They found the following hazard ratios for high consumption vs low consumption: 1.20 sugar sweetened beverages, 1.20 full fat milk, 0.98 fruit juice, 0.96 artificially sweetened beverages, 0.88 low fat milk, 0.79 tea, 0.77 plain water, and 0.74 coffee. The ratios were similar for the development of cardiovascular disease.

Also, replacing sugary beverages, artificially sweetened beverages, or full fat milk with coffee, tea, or plain water “was consistently associated with lower all cause mortality.” More at British Medical Journal (free full text).

Females (especially) take note: A plant-based diet could increase bone injuries

The relationship between eating disorders and possible bone injuries has become one of the most investigated and most important in endurance sports. It started decades ago with the Female Athlete Triad and has more recently turned to male eating disorders, especially in sports where low weight might confer a performance advantage such as running and cycling. 

A big question: Do females have greater risk than males? Here are several recent studies that increase our understanding of bones and vigorous exercise.

This “critically appraised” review of the topic found “low-moderate evidence” of a link between eating disorders and bone injuries in female athletes. Less is known about males. More at J of Sport Rehabilitation.

“Bone stress injuries have plagued the military for over 150 years,” afflicting up to 10 percent of new recruits. The primary risk factor is “too much training, too soon.” Women have about twice the bone injuries of men. Good nutrition can help but also “exposure to stress, sleep loss, and medication is likely harmful to bone.” More at J of Science & Medicine in Sport (free full text).

A study of 16,000+ U.S. adults from 2005 to 2018 found “hidden dangers” to a plant-based diet on bone health. Specifically, plant-based diets, which are often recommended for their potential health and environmental benefits, are “associated with decreased bone mineral density in a nationally representative population of U.S. adults.” The most protective foods are: vegetables, refined grains [yeah, I don’t get it either; but that’s what they reported], animal fat, eggs, and meat. More at Nutrients

Here’s a super deep dive into sacral bone stress injuries in runners with specific advice on training and diet errors that might be causative factors. As well as solid, healthy guidance on getting back onto the road. More at Pogo Physio.

Lastly, a group of world-renowned exercise nutritionists have concluded that consuming sufficient carbs, even more than total calories, is the key to maintaining strong bones in endurance exercisers. In a 6-day study with elite race walkers on a low-calorie diet, they found that: “Carbohydrate may be key for maintaining bone formation during prolonged exercise, but both overall energy and carbohydrate are necessary to support bone formation at rest and limit exercise-related bone resorption.” More at J of Bone & Mineral Research (free full text).

What’s the truth about exercise and improved brain function?

When he’s got time left over from his work at Outside Online, Toronto’s Alex Hutchinson occasionally writes newspaper articles. Here he looks at some recent reports that have cast doubt over one of our fondest beliefs--that exercise is as good for the brain as it is for the eyebrows-down.

One rigorous review found only “negligible” evidence that exercise produces cognitive benefits. On the other hand, another high-quality review used Mendelian randomization to find “significant associations” between moderate and vigorous exercise (like running) and “increased cognitive functioning.” [Mendelian randomization is a statistical technique that edges close to cause-and-effect by using the known genetic makeup of subjects.] The paper observed no evidence of the same from “average physical activity,” ie, vacuuming the house, mowing the lawn, etc. More at The Globe & Mail.

If you’re a marathon runner, you might be doing good work for your hippocampus--the part of your brain responsible for regulation of stress, and also spatial navigation. At least that was the finding that popped out from MRI imaging of 73 marathon runners vs 52 healthy, matched controls. The marathoners seemed to have “a hippocampal volumetric reserve that protects against age-related hippocampal deterioration.” More at Medicine & Science in Sport & Exercise.

SHORT STUFF you don’t want to miss

>>> Run for the future: More and more shoes and running fitness apparel are made from recycled and sustainable materials.

>>> Nothing special: Muscle injuries (and concussions) are more prevalent in high schoolers who specialize in a particular sport and/or spend more than 8 months per year in one sport.

>>> Outdoors vs treadmill: Running outdoors provides “greater feelings of revitalization and positive engagement, decreases in tension, confusion and anger and depression, and increased energy.”

GREAT QUOTES make great training partners.

“The secret of getting ahead is getting started.”

--Mark Twain

That’s it for now. Thanks for reading. See you next week. Amby

April 27, 2023

Surprising training methods of the world’s fittest 75-yr-old

(Disclosure: I wrote the below-linked article.) In a recent lab test, Hans Smeets broke the unofficial world record for the highest vo2 max by a 75 year old. His score was roughly equivalent to that of a young man in his mid 20s. And Smeets isn’t just a lab rat. He has won dozens of world championships in his age group, excelling in particular in the 800 meters and 1500 meters.

How can an old guy be so fit? Smeets admits that probably 50% of his success comes from good genetics. The other 50%, according to exercise physiologist Bas van Hooren, is Smeets’s consistent training through the last several decades. Surprisingly, much of this training has been slow. Smeets says he often walks up several of the biggest hills on training routes near his home. 

“Speed training produces more damage,” notes Van Hooren. “By doing higher volumes of easy training, masters athletes might gain positive adaptations with less damage and need for recovery.”

More at Outside Online.

The 6 worst foods you can eat (and the 5 best)

A big new Harvard study delved into the likely causes of diabetes, a major global health concern of the present and future, particularly as more people gain access to more processed foods, sugar, and fats. I use the word “cause” loosely as these sorts of observational diet studies can’t actually prove cause and effect. That said, I don’t think many doubt the conclusions of this paper.

It gathered data from 184 countries and pinned increasing rates of diabetes squarely on “suboptimal diet.” In particular, certain “bad foods” (my usage, not from the paper) were a major problem. The six worst of these: refined rice and wheat, processed meats, unprocessed red meat, sugar sweetened beverages, potatoes, and fruit juice.

It’s particularly important to limit these foods because they contribute 60.8% to the diabetes burden.  And you can only reduce your diabetes risk by 39.2% by consuming “good foods” (my usage). The best of these: whole grains, yogurt, fruits, non-starchy vegetables, and nuts and seeds. 

More at CNN.com and free full text of the journal report at Nature.

What shoe company won the Boston Marathon?

Or could I have prevented my post-Boston soreness by racing in a different shoes? (I wore a pair of Saucony supershoes.) 

Everyone’s talking about the fact that the top 3 male finishers at Boston wore Adidas shoes, not Nikes. Meanwhile, the female winner wore shoes from “On,” a company that has enjoyed big market success due to the street appeal of its shoes, and has also sponsored a visible elite team. However, its earlier running shoes were a bit clunky. Apparently that has changed.

Now comes the question: Have other brands caught or even surpassed Nike, the leader since its stealth introduction of super shoes in 2016? Here’s a shoe count from Outside Online. It tallies who wore what among the top 25 male and female runners at Boston. The podium looked like this: Adidas--16; Nike--14; Asics--8.

A British newspaper story drew fascinating comments from England’s 42-year-old elite marathoner Chris Thompson, and runner-biomechanist Geoff Burns. Thompson said he’s hearing about runners logging 160+ miles a week in training, because the super-foams provide dramatic recovery-benefits. “There’s no shying away from it: super shoes have a huge impact on performance,” says Thompson, who pegs that impact at 4 minutes for an elite male marathoner.

Burns says the benefit is relatively more for slower runners. Why? Because the fast folks encounter greater wind resistance, which subtracts from any performance gain. Slower runners don’t face much wind resistance, so they don’t have to subtract anything from their shoe-enhanced boost. More at The Guardian.

Not for women only (but mostly)

More research is beginning to focus on women-only subject groups, as women may react differently than men to exercise and other stressors. For example, it’s fairly well established that women runners have twice (or more) the risk of bone stress injuries. What to do?

This study measured the effect of strength training on bone mineral density (BMD) of college-age female runners. When the runners added 16 weeks of strength training to their typical training program, they increased their total body BMD. This could lead to a decrease in bone injuries. More at The J of Sports Medicine & Physical Fitness (free full text).

Another paper looked at ways female runners change their stride, through an “internal focus” or an “external focus.” The goal was to lower impact forces of each stride when the foot hits the surface. Result: Participants were most successful at lowering impact forces when they employed an external focus, such as looking around at their surroundings. The researchers hypothesized that this approach worked better because it helped maintain a relaxed running form, which lowers impact forces. More at J of Sport Rehabilitation.

Speaking of forces, females apparently run with less pain and greater efficiency when they restrict breast movement. Researchers asked 13 recreational women runners (average age 37, average cup size “C”) to perform 3 separate treadmill running trials in a lab. The women ran with: 1) no bra; 2) a low-support bra; or 3) a high support bra.

Subjects ran most comfortably and efficiently with high-support, which increased their knee “stiffness” (usually associated with higher running economy) while decreasing their “knee joint excursions,” or bending. The authors stated that their paper emphasized “the importance of proper breast support in female runners.” More at Frontiers in Sports & Active Living (free full text).

How to get the most from interval training

Interval training is well-established as a valuable method for endurance runners. It may also be a bit dangerous, injury-wise, because you can get overly fatigued in a hard interval session. And that could be the trigger leading to injury.

So here the investigators performed a systematic review of studies to see if interval training (IT) might affect running-form biomechanics in a way that would increase injury risk. They found 9 papers where: “(1) participants were experienced runners, (2) the training sessions included IT, (3) the studies evaluated the acute effects of the IT training sessions (4) and the studies evaluated kinematics parameters as outcome measure.”

Result: The rest period (the “interval”) between fast repeats turned out to be a significant factor. Specifically, when doing fast repeats of 200 meters to 1000 meters, the runners need longer recovery periods (2 to 3 minutes) to prevent the kind of muscle fatigue and bad running form that could produce an injury. For longer, slower repeats greater than 1000 meters, recoveries can last just a minute or 2. 

Conclusion: “Coaches and athletes must consider the relative intensity and recovery periods of IT, and the type of IT, to prevent excessive fatigue which can negatively affect running kinematics.” This is true because “ IT sessions performed at high intensity lead to significant acute changes in running kinematics, whereas medium intensity IT did not cause acute kinematic changes.” More at Gait & Posture  (free full text).

Two great ways to boost running economy (with a slight edge to plyometrics)

We’d all like to improve our running economy for the same reason we’d like to get more miles/gallon from the car we drive: It makes life better, more efficient. Some past studies have shown that strength training and plyometric exercises can improve running economy, so in this new paper the authors pitted one against the other.

Thirty-one male recreational runners were divided into two groups. One spent 8 weeks doing its normal modest running, plus 40 to 80 minutes per week (in a gradually increasing amount) of dynamic strength training. The second group did the same, only with plyometric training. 

The dynamic strength exercises included hill running, squats, step jumps, and the like. The plyometrics included downhill running, drop jumps, hopping, and the like.

Result: Both groups improved their running economy about 2 percent on average, with a slight edge for the plyometrics. Surprisingly, the improvements occurred “with minimal to no changes in running biomechanics” such as stride frequency or contact time. 

In other words, plyometrics and dynamic strength exercises both improve running economy, but it’s hard to say exactly how they do this. The authors speculate that the mechanism is better “neuromuscular adaptation.” More at Sports Biomechanics (free full text).

Downhill running benefits keep adding up

My legs have mostly recovered from this year’s bashing in the Boston Marathon. But the post-Boston recovery process is never fun, so I’ve resolved to do more downhill training next year, guided in part by some new research. 

The first study reported the results of 10 downhill training sessions undertaken over a 4-week period with several days of rest between sessions. The workouts got longer (from 15 minutes to 30 minutes) and harder during the 4 weeks, but were maintained at “moderate and tolerable running speeds.”

After four weeks, the subjects exhibited “Rapid neuromuscular adaptations of the knee extensors” of a “magnitude typically seen after a period of very high-intensity eccentric resistance training.” However the short training period and/or modest running intensity were not enough to boost aerobic capacity.

The investigators nonetheless believe that downhill-run training can increase “physical performance in athletic populations by providing a safe and effective alternative method (to resistance training) for inducing strength gains.” Also, since downhill running produced positive neural adaptations without adding muscle mass (weight), it could be particularly helpful for distance runners. More at European J of Applied Physiology (free full text). Here’s an infographic summarizing the results.

Another paper examined changes in biomechanics that occur after a 30-minute downhill run. It increased contact time (duty factor) and decreased flight time, which aren’t optimal for efficient running. Also, subjects reported an increase in muscle pain and perceived exertion. However, when the same downhill run was repeated 3-weeks later, with no special training in between, these biomechanical changes were much less pronounced. Now the subjects were more efficient while also reporting less pain and effort. 

This improvement is called a “repeated bout effect.” The paper showed that just one session of downhill running produced positive outcomes 3 weeks later. You don’t have to do a lot of downhill training, because a little bit goes a long way. More at European J of Sport Science (free full text).

Here’s a magazine article from Runner’s Tribe with tips to improve your downhill running. It emphasizes a short stride and high stride frequency. Here’s more of the same from a Swiss-based mountain runner. Finally, here’s a great article from HIIT Science that explains both the cons and pros of downhill training.

What happens when you train on a treadmill that tilts side to side?

Imagine running on a treadmill that rolls side to side like a ship in a wavy sea. You probably wouldn’t enjoy that, but it’s close to what trail runners face in their favorite environments. Likewise, the treadmill utilized in this experiment could tilt 7 degrees to each side, and the tilt could change every 1 to 3 seconds.  

Researchers put 20 high fit runners on this treadmill to see how it affected their oxygen consumption and muscle activation from 8 lower limb muscles. I would have expected some big changes, but that’s not what was found. Apparently our bodies are well tuned for running across Earth’s many undulations. Of course, uphill slope and running speed do make a big difference. More at International J of Environmental Research & Public Health.

SHORT STUFF you don’t want to miss

>>> Get in the zone: How to find the right heart-rate training zones for different workouts.

>>> The eyes have it: Exercise produces molecular changes that “may confer protection against retinal degeneration.” (free full text).

>>> Good carbs, bad carbs: What’s wrong with carbohydrates? Nothing. If you choose the right ones.

GREAT QUOTES make great training partners

"You have to forget your last marathon before you try another. Your mind can't know what's coming."

--Frank Shorter