June 23, 2022

THIS WEEK: To run your best marathon, max out on in-race carbs. 11 key mental skills for top performance. All you need to know about hydration. Concurrent training: two for the price of one. New molecule boosts weight loss. Women run faster with “high support” bras. How to prevent shin splints. And more.

Aim for MAX carb intake (from any source) for best endurance

A team of world class researchers has for the first time shown that it doesn’t matter where you get your carbs--drinks, gels, blocks, bars--as long as you get plenty. In fact, they recommend aiming for 100 to 120 grams per hour (400 to 480 calories). That’s really high, but also in line with other recent studies that have runners aiming to take on more fuel on the race course.

Here, subjects cycled for 3 hours, and then performed a high intensity test to exhaustion. The study design was a randomized, cross-over trial. Despite the high-carb intake, subjects reported “minimal symptoms of gastrointestinal distress.”

While the researchers found no significant differences between the carb sources, they seemed impressed by new semi-solid foods (chews, or blocks) that don’t have the same issues as prior bars with fiber, protein, and fats. They also noted high oxidation rates (a good thing) with a “mixed” routine that included one drink, one gel, and one chew per hour. This strategy “reflects the real-world fueling practices of elite endurance athletes.” Each provided 30 grams of carbohydrate in a formulation of 1:0.8 of maltodextrin or glucose to fructose.

Importantly, subjects carbo-loaded the day before testing and had a high carb meal three hours before beginning their exercise test at 10 am. This mimics the advice given to endurance athletes before a competition, and differs from tests on subjects who report to the lab in a fasted condition.

A cautionary note: Subjects were cyclists, not runners. Runners are known to have more problems with GI distress than cyclists, due to the increased “sloshing” that results with running. So, practice first. More at J of Applied Physiology.

11 key mental skills for elite performance

Distance running success is contingent on a number of things including a high vo2 max and high mental skills or toughness. Who hasn’t finished a race and thought, “Damn, I could have run so much better if only I was tougher or smarter at point XYZ.” 

Which is good reason to read Alex Hutchinson’s Outside Online column on “11 Mental Skills That Make an Athlete Elite.” After all, there must be one or seven that you could perform better yourself. We all have days when we’d like more Motivation. And if Eliud Kipchoge would be willing to share some of his Self Confidence, that would be swell too.

Bonus: The mental skills we develop in sports likely have strong “carry over” value in other areas of life. As the researchers note: “By reaching their full psychological potential, athletes increase the likelihood of achieving success in High Performance sport and building a strong foundation for realizing other feats in society.” More at J of Applied Sport Physiology.

What you need to know about hydration

My mail box got flooded (pun intended) this week with press releases from companies noting that June 23 is “National Hydration Day.” Actually, I think every day should be national hydration day, but without the capital letters. It’s important and simple--not deserving the hysteria that companies bombard us with. 

For example, in Australia they don’t think much about hydration, says a new paper. They just drink when they sit down for meals. In the U.S. we tend to “target” a certain number, and focus on drinking around activities like sports. Result? Adults in both countries drink the same amount, and meet their daily needs. More at Frontiers in Sports & Active Living.

For runners, the rules of hydration are clear and basic. Drink when thirsty. Don’t worry about races and workouts up to 60 minutes; they don’t require a hydration plan. In longer events, drink steadily from the start, and limit your body weight loss to about 2 percent. Remember that foods supply about 20 percent of your daily water need. Stay healthy, and maintain your body weight from day to day.

Concurrent training: two for the price of one

Runners tend to run a lot, and gym rats tend to lift a lot, but you can combine the two with good results. This is called “concurrent training.” You don’t actually do both at the same time; you have to decide which comes first. For runners, the evidence supports doing your aerobic work first, then adding some strength exercises. 

A new systematic review and meta analysis finds that concurrent training “does not compromise muscle hypertrophy and maximal strength development.”  Here’s a deep dive into the research. Here’s the paper itself at Sports Medicine. Another article has a very simple, clear Table to show your options, plus additional supportive details. More at Tonal.

New molecule--Lac-Phe--appears to boost weight loss efforts

It has long been known, as a general rule, that moderate exercise tends to stimulate appetite while hard exercise limits it. Now researchers have found a possible mechanism for this effect. It could be a previously unknown molecule that has been named “Lac-Phe”, as reported at the NY Times. The “Lac” comes from lactate, which has recently been associated with “greater suppression of the hunger hormone ghrelin and subjective appetite.” 

Much of the Lac-Phe research has been conducted in mice, but Lac-Phe has also turned up in race horse and human studies. Conclusion: “Lac-Phe reduces food intake without affecting movement or energy expenditure.” This seems to mean that any time you exercise at or beyond your lactate threshold, you probably decrease your appetite. More at Nature.

Elite cyclists train easy 90 percent of the time

I would have thought top-rank cyclists would train harder than top runners, since they get to sit smooth and comfy above fast-spinning tires (no pounding!) After all, the pounding effect of running is a big reason for our 80/20 training. On the other hand, cyclists often spend 5 to 6 hours/day on the road, and apparently that’s enough to push their “easy zone” effort up to 91 percent. That was the case in this paper that investigated the training of 3 cyclists who finished in the top 5 at the famous Giro d’Italia multistage race. They also tapered far less--only about 12% of total mileage--than the 40 to 60% recommended by most experts. More at Scandanavian J of Medicine & Science in Sports. 

This is different: Exercise increases knee size

We all like to reassure Auntie Sue that running won’t damage our knees, but frankly it’s not easy to explain. I often refer to stronger muscles and tendons--a good thing. But here’s another explanation. In a large Finnish study that used accelerometers to gain an objective measure of leg movement and intensity, those who exercised more had  larger tibiofemoral joint size. This bigger joint could then accommodate more stress across the joint, potentially reducing tissue strain and preventing knee problems.The researchers used a rare (but nice) word to describe this. They speculated that exercise enhances the knee’s “robusticity.” More at BMC Musculoskeletal Disorders.

High-support bra best for female running performance

The female breast in motion has been described as “a wobbling mass on a rigid torso” (not, ahem, by me.) Nevertheles, the point is well taken. Excess motion always detracts from efficient running. Here, researchers measured the oxygen consumption of 12 female runners while wearing a “low support” bra and a “high support” bra. High support wins the race. Conclusion: “Sports bra support alters the metabolic cost and economy of running.” More support limits motion, which makes you faster. More at ACSM Abstracts.

What causes shin splints, and how to prevent them

Shin splints and the more serious tibia stress fractures are common injuries among runners. This systematic review and meta analysis looked into ways that changing running technique and/or changing equipment could reduce tibial loading rates, and therefore injuries. Main findings: Risks are increased by running barefoot or in unfamiliar minimalist shoes, running faster, overstriding, and wearing motion-control shoes. Risks can be diminished by running on a treadmill or using “targeted biofeedback” to adjust stride. More at Sports Medicine.

SHORT STUFF you don’t want to miss

>>> Nike super shoes and Saucony racing flats produce similar changes: higher stride frequency, longer stride, better economy.

>>> For healthy feet, wear running shoes even when you’re not running, as they place “less burden on the overall foot.”

>>> Runners suffering sudden cardiac arrest at races will have “a high survival rate and favorable neurological outcomes” when they receive rapid chest compressions and defibrillation.

GREAT QUOTES make great training partners

"Every morning we are born again. What we do today is what matters most."--Buddha

That’s it for now. Thanks for reading. Stay well, and see you next week. Amby


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