The Latest Endurance Performance Research From The Boston Marathon
I get excited every time I see a Boston Marathon research paper that looks into performance variables linked to marathon finish time. This is one, and the results are important for all runners.
The study team consisted of top physicians from Boston area medical teams that treat runners, members of the Boston Marathon Medical Team, and other international marathon experts.
They sought an answer to this key question: How do runners perform in the Boston Marathon if they have been consuming too few daily calories in training. This is known as Low Energy Availability (LEA).
In the researchers’ own terms: “This is the first large study conducted at a mass-endurance event linking athletic performance and medical risk to self-reported problematic LEA.”
Some marathon runners deliberately follow a weight-loss diet in training because they believe that lower body weight will make them faster on race day.
Of course, everyone wants to run their best when they get to Boston.
Results: A survey of 1,030 Boston entrants found that 42.5 percent of female runners and 17.6 percent of males reported a calorie intake that would be considered LEA. Compared to similar participants of the same body size and training, those with LEA “had much slower times on race day,” said first author Kristin Whitney.
In addition, the LEA runners were 1.99 times more likely to require race-day medical attention, and 2.86 times more likely to experience “a major medical encounter” on Boston Marathon day.
Therefore: “Our novel findings support the negative athletic performance outcomes and increased medical risks associated with LEA-I in both female and male marathon athletes.” More at British J of Sports Medicine with free full text.
The authors also found that LEA runners were more likely to miss training days due to illness or injuries to bone and soft tissue.
A paper at The FASEB Journal (free full text) reported on a crossover experiment in which well trained female runners reduced their caloric intake by more than 50% over a 2-week period.
Result: Time to exhaustion on a treadmill test was reduced by 18.9% after 2 weeks on the low-cal diet. During that time, subjects lost 4.1% of their body mass. Strangely, a number of exercise measures didn’t change, including glycogen supply and “muscle 02 utilization.”
The researchers were left wondering “whether LEA per se affects aspects of training quality/recovery.” Or if there was something else going on.
Run This Amount Each Week To “Feel Your Best”
“Subjective vitality” isn’t something you hear every day in discussions of optimal health. And your doctor doesn’t mention it during your annual checkup.
But you know you want it, because it’s a general measure of your energy, vigor, and “aliveness.” Sign me up; I’ll take another spoonful.
Here, researchers wondered if the amount of running we do each week is related to our subjective vitality. They looked at both the total number of workouts, and the length of each workout.
Result: Subjective vitality didn’t differ between the sexes, and also was not different among age groups. Good. It was greater “with weekly training frequency up to 5 days/week.” It also increased in relation to longer workouts before reaching a top level at 90 to 120 minutes per workout.
Conclusion: “There is a dose–response relationship between both weekly training frequency and training session duration, and mental health benefits in recreational runners.”
It appears that you reach maximal subjective vitality with 5 runs a week at a pace comfortable enough that you can hold it for 90 minutes. That’s 450 minutes in total--considerably more than the minimal federal guidelines for aerobic fitness--75 to 150 minutes/week. More at J of Functional Morphology & Kinesiology with free full text.
Here’s The #1 Hard Workout For Optimal Recovery
This is a great study that investigated how different “exercise patterns” affect recovery after a workout. Basically, it’s a test of interval training vs more moderate, continuous training. The goal is to achieve X amount of positive training-impact with the least amount of post-workout recovery strain.
The subjects were healthy active females and males from 18-39. They each did three treadmill workouts on separate days.
All workouts were designed to include 30 minutes of running at about 90 percent of tempo pace. That’s a hard session, but not a killer.
One day they did their 30 minutes continuously; one day they did 5 x 6-minute intervals with 2-minute recoveries; and one day they did 15 x 2-minute intervals with 2-minute recoveries. The researchers wanted to know how the three similar but different workouts would affect the heart’s recovery process.
To do this, they measured the runners heart rate recovery, heart rate variability, blood lactate, and blood pressure during and after the workouts.
Result: Heart rates recovered faster after the 2-minute intervals, which also produced the lowest blood lactate levels. Also heart rate variability (a measure of nervous system recovery) was better after the 2-minute intervals.
Conclusion: “Exercise pattern influences the physiologic response to exercise.” Moreover, higher frequency intervals like 15 x 2-minutes can “expedite post-exercise recovery while maintaining total work performed.” More at Medicine & Science in Sports & Exercise.
How To Heal (And Prevent) Shin Splints
Here, researchers conducted a randomized, controlled trial with 40 runners who had been suffering from shin splints for at least a month. None of the subjects was overweight, which eliminated a factor that might otherwise have contributed to shin splints.
Two groups “received a selected physical therapy exercise program for 8 weeks.” The experimental group also received “additional functional hip abductor strength training.”
This included exercises like the single-leg bridge and lateral step ups. (Short YouTube videos here, single-leg bridge; and here, step ups.)
Result: After 8 weeks, the group that did the hip abductor exercises had “significantly improved reductions in contralateral pelvic drop angle and dynamic knee valgus.”
Conclusion: This targeted hip strengthening reduced “muscle weakness and movement dysfunction” and lower chances of a shin-splints recurrence. More at J of Orthopedic Research & Surgery with free full text.
Can You Change Your Muscle Fiber Type?
Most runners know whether they’re the fast, sprinter type or the more enduring marathon type. They might also find themselves more muscular or more at the scrawny end of the scale.
The first are said to have an endomorph body type, while the latter are termed ectomorphs. Endomorphs are more likely to have a predominance of fast-twitch muscle fibers, while ectomorphs have more slow-twitch fibers--good for long distance events like marathons.
The big question has always been: If you have predominantly one type of fiber, can you train to increase the other type? Say, you’re a quick 400-meter runner, bolstered by your fast-twitch fibers. You decide you want to enter a marathon. Can you train in a certain manner to increase your slow-twitch fibers and thereby increase your marathon endurance?
It used to be thought that this was near impossible. But no longer. Alex Hutchinson reviewed the latest research in his column at Outside Run. He concluded: “Fiber type isn’t destiny, and it doesn’t have to determine your athletic goals.” That’s the good news.
But we still have lots to learn. Especially: How to determine your exact muscle-fiber ratio, and what specific training you should do to maximize changes.
By chance, a newly-published study uncovered a Chinese herb that might change fast-twitch fibers to the more fatigue-resistant slow-twitch fibers. The herb is Salvia miltiorrhiza (red sage). It yields a compound named Sodium Danshensu.
The study concludes: “Sodium Danshensu promotes muscle fiber transformation from the glycolytic type to the oxidative type.” More at Frontiers in Pharmacology with free full text.
The Problem With Standing Desks
Standing desks and treadmill desks enjoyed their 15 minutes of fame a decade ago. They seemed an easy solution to the too-much-sitting problem that faced many of us for long periods of time each day, mainly at work.
If you stood up at your desk, the theory went, you would at least be engaging muscles that might burn a few calories and release healthy enzymes. And if you actually moved by walking slowly at your treadmill desk, that could have bigger and more positive effects.
Since then, research and personal experience have added some clouds of reality to the early thinking. I tried a “walking desk” and found it disorienting. I’m sure I could have adopted, but it wasn’t going to be easy.
Instead, I used a standing desk for several years. Then I got tired of it--literally tired. I’m back to sitting at my computer now, and making sure to get up for some pushups and stair climbing every 30 minutes or so.
Recently a new study of 83,000 individuals has concluded that a standing does little/nothing to fight heart disease. In fact, too much standing could lead to circulatory issues like varicose veins, orthostatic hypotension, and other blood-flow concerns. Sitting more than 10 hours a day is particularly “deleterious.”
Why don’t standing desks work better? Because you aren’t moving. You need to move to stimulate your muscles and ultimately your health.
Walking at a treadmill desk? That’s probably fine. It just requires an investment and an adjustment period. More at International J of Epidemiology with free full text
Older Runners Can Help Change Social Norms
A recent paper presented at the Georgia Sociological Association will strike a chord with many runners past 50. And, I suspect, younger runners as well.
It’s titled “Running past Fifty: The Habit and Joy of Movement.” It asks the basic question: Why do some runners keep running into older age and slower performances?
After all, as University of Georgia professor James Dowd writes: “The reality of aging is clearly evident. Older runners are slower, less vigorous, and without the striking beauty of the young.”
Across the population at large, older individuals are viewed as “nice but incompetent.” In particular, they don’t do weird things like running 5Ks, half marathons, and marathons. Most choose the rocking chair and TV.
Dowd finds two principal reasons to explain persistent, older runners: 1) Running has become a habit for them, and thus a “foundational part of their identity;” and 2) Running brings them “joy and a sense of profound well-being.”
Joy and profound well-being? Who doesn’t want that as the biological clock ticks past 50, 60, 70, and beyond?
Dowd bases his findings on long interviews with 61 runners over the age of 50. Reviewing the interview transcripts, he quickly noted that “the joy of running derives from the actual movement of one’s body, but also from the opportunity of joining with friends on practice runs or at races.” This is the social component so often mentioned in healthy-aging articles.
There is also “the pure pleasure of being in nature,” whether a forest trail or “a bosky suburban neighborhood filled with the ambient sound of birds and the rustling of leaves.” I appreciate Dowd’s observation that you don’t have to live next to a state park to appreciate the natural environment.
I’ve always believed in running out my front door rather than driving to some special location. But once out the door, I quickly steer to the greenest, most serene streets and neighborhoods.
Ultimately, Dowd wonders if older runners can change the national narrative on aging and loss of health/vigor. He acknowledges that this won’t come easily. Yet he concludes with several powerful, lyrical sentences.
“The common struggle of runners to finish the course creates the seedbed for a generative impulse that, like the flow of water in a creek, will gradually but surely change the shape of that creek. Unwittingly or not, runners are agents of positive social change.” More at Research Gate with free full text.
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