August 31, 2023

A new dimension in marathon training could yield the key to success

Exercise physiologists have been picking apart the marathon for a long time, and have almost unanimously agreed that there are three keys to top performance. They are: 1) high vo2 max; 2) high running economy; and 3) high fractional use of vo2 max (similar to high lactate threshold).

Now British endurance expert Andy Jones, who has worked with everyone from Paula Radcliffe to Eliud Kipchoge, is formally proposing a “fourth dimension” to marathon performance. He’s calling it “resilience.” Others have used terms like “durability” or “muscle fatigue resistance.”

They’re all talking about the same thing, and it’s not the way your body performs when you are fresh and primed for a hard run on a laboratory treadmill. Instead, resilience is the way your body performs after 20 miles of bone/muscle/cardio crunching road race effort. It’s the factor that often determines who wins a marathon, and who doesn’t.

We don’t know much about resilience because little laboratory data has been gathered. For one thing, you’d have to pay subjects a lot to undergo the torturous testing. Also, it would take a lot of laboratory time, effort, and equipment (ie, $$$ again).

Some of the barriers are being overcome by lightweight digital devices and ingestible micro sensors that can monitor internal conditions. Still, it’s a long road ahead. 

Anyway, that’s the backdrop to Jones’s paper, “The fourth dimension: physiological resilience as an independent determinant of endurance exercise performance.” The paper explores “key variables that are not static but subject to deterioration during endurance performance.”

As marathon runners, we mainly want to know how we can improve our resilience. Jones has several ideas. You gotta wear super shoes, of course. We see that in the way top marathon runners are now running negative split races. At London last April, Kelvin Kiptum ran 61:40 for the first 13.1 miles, and 59:45 for the second half to finish in 2:01:25. In addition, the more carbs you can consume on the road, the longer you’re likely to remain fueled and efficient.

Jones also believes that “age and/or consistent, long-term, perhaps high volume, training may play an important role.” Studies of runners like Paula Radcliffe and Eliud Kipchoge have shown that they can improve steadily over a decade or more if they continue their high-level training.

Other possible resilience enhancers: “regular training in a fasted and/or glycogen-depleted state (through, for example, twice-daily training or overnight carbohydrate restriction).” And: “endurance training sessions where the speed is held constant at close to race effort or progressively increases with time (as practiced by, for example, Eliud Kipchoge).”

This is just a beginning list. More is sure to come as “resilience” receives more investigation and research. More at The J of Physiology with free full text.

Should you consider carrying extra weights while running?

I still own a pair of ankle weights that I bought in my adolescent running years. I thought the weights would make my run training more difficult, and that the increased training effort would stimulate improved race-day efforts. At the time, I pretty much believed in the “more is better” approach to running.

My brief experiment didn’t end well. I can’t say it’s because the weights failed me; I stopped using them because it was no damn fun. They made my running clunky and uncomfortable, so I relegated them to the basement cobwebs.

However, others are still testing the idea. When running biomechanists added 1 kilogram (2.2 pounds) to each foot of runner-subjects, they observed “only moderate kinematic” changes in movement patterns. Things were quite different at the joints though, where maximum joint forces increased as much as 40% for knee extension and 50% for joint power of hip generation, both in the late swing phase of running.

Conclusion: “These changes have implications for people who run with added mass on their legs for sport/strength.” I’d say the implications include: Be very, very careful not to overdo it. In fact, I’ll never again try my ankle weights for actual running. Maybe for the bike, elliptical, or StairMaster. But not on the road. More at Applied Ergonomics.

A little extra weight is easier to carry on the upper body than on the lower legs, and ultra runners often find it helpful. After all, they might have to go it solo for several hours between refreshment checkpoints. Meaning: They have to carry their own fluids and fuels.

To give this crowd some useful data, researchers recently tested runners on a laboratory treadmill while carrying nothing, 5 kg (11 pounds) or 10 kg (22 lbs) in a weighted vest.

They found that the 22-lb pack had an overall negative effect, as it increased ground contact time. On the other hand, the 5-lb pack seemed to hit a sweet sport. It didn’t alter runners' basic biomechanics, yet managed to increase leg stiffness--generally thought to be a good finding linked to better running economy. 

Conclusion: Running with “an additional load equivalent to +5% body weight” yields “improved running performance.” But more isn’t better. In fact, adding another 5% of body weight turned things around and produced a negative result. More at Sensors.

A simple (proven) way to find your max fat-burning zone

Most of the time we runners don’t worry much about max fat burn. You don’t win races that way, or hit your goals. But there are still situations where max fat burning might become interesting. Maybe if you’d like to lose some body fat. Or if you want to try one of those training regimens aimed at teaching your body to spare glycogen during loooong efforts.

If so, the big question becomes: Where the heck is my max fat burning zone? That’s the answer we get from this systematic review and meta regression paper that delved into 64 previously published reports on max-fat-burning.

Result: Assuming that you have a body-fat percentage under 35%, your max fat burn will occur when you are exercising in the range from 57 to 64% of your max heart rate. Sixty percent seems like a nice round number that should be close. When you run or exercise at a higher heart rate, your body begins to use carbohydrates as the preferred fuel source. 

Biological sex did not appear to influence the results, and heart rate was more effective at determining max fat burn than percent of vo2 max. That’s good, because heart rate is much easier for individuals to monitor. More at Sports Medicine.

SHORT STUFF you don’t want to miss

>>> 9 reasons why runners should improve their ankle strength

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

NOTE: If you were a subscriber to the complete, full-text version of RLRH for $4/month, you would also have received new articles on:

# Why a 10-day training “week” could be better than 7 days.

# 10 steps to a faster marathon

# How to choose the best overall diet for athletic performance

# How you can “engineer happiness” on the run

# “Active recovery” improves performance in your next workout

# 6 fixes for common training errors

# More evidence on sodium bicarbonate for greater endurance

# A motivational “No Fear” quote from Born to Run author, Christopher McDougall

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