Barefoot or Shod? A Question of Faith & Science: Science Says It's Safe and Economic, Practitioners Say "It's Making Me Faster & Helped Me Get Rid of Nagging Injuries!"

Minimal or no shoes, trendy, healthy and performance enhancing?

Honestly, I am not even sure if it's a question of faith and science. I think for many people out there it is more a question of faith or science. Now some of you may think: "Well, of course, science says: It's bullocks. Faith says it's 'right' to run barefoot." Right? Wrong!  No, I don't want to tell you what to do. I want to tell you about the scientific evidence in favor of barefoot running. Evidence as it is presented in "Barefoot running survey: Evidence from the field" a recent paper by David Hryvnial, Jay Dicharry and Robert Wilder that's about to be published in one of the upcoming issues of the Journal of Sport and Health Science that's based on data from more than 500 runners (Hryvniak. 2014).

Not everyone will do his HIIT sprints barefoot, I think, but maybe minimally shod?

Never Train To Burn Calories!

Tabata = 14.2kcal /min ≠ Fat Loss

30s Intervals + 2:1 Work/Rec.

Making HIIT a Hit Part I/II

Making HIIT a Hit Part II/II

Triple Your Energy Exp.

Prior studies have found that barefoot running often changes biomechanics compared to shod running with a hypothesized relationship of decreased injuries. The study at hand, which reports the results of a survey of 509 runners and does therefore represent both the "faith" and "science" appears to confirm these findings, as the majority of respondents report benefits and/or no serious harm from transitioning to barefoot or minimal shoe running.

Figure 1: Impact of switching from shod to barefoot-running on performance (Hryvniak. 2014).

As the data in Figure 1 clearly confirms, 67% of the surveyed runners reported noticeable improvements, 19% even say their performance increased significantly.

There is evidence from controlled trials that running barefoot reduces the oxygen cost and thus the running economy (Hanson. 2011)

What does previous research say? Where barefoot and shod populations co-exist, as in Haiti, injury rates of the lower extremity are substantially higher in the shod population (Robbins. 1987). The same often-cited study by Robins & Hanna does also confirm that running-related chronic injuries to bone and connective tissue in the legs are rare in developing countries, where most people are habitually barefooted. Whether these associations are of correlative or causative nature, however, is hard to tell, because controlled trials are rare.

This, in turn, is in contrast to studies on running economy most of which shown that wearing shoes increases the energy cost of running (Burkett. 1985; Hanson. 2011, cf. figure to the left) - in other words, it made the runners run more efficiently.

What's even more intriguing, though, is the injury balance. While 64% of the runners report that they have not had any injury, foot injuries (reported by 20% of the participants) may have become slightly more common.

Figure 2: Barefoot runners don't run barefoot, all the time, but there is hardly a terrain they avoid.

Unlike the grassy fields, which are the most frequented running grounds, city streets and sidewalks are not exactly "safe" places to run are where the study participants run more than 50% of their weekly mileage. Against that background it's also surprising that the number of knee injuries, injuries of the hips, lower back and ankle decreased in spite of the absence of the highly advertised "buffers" professional running shoes are supposed to offer.

Figure 3: Answers to the question " Did you have Achilles or foot pain when you initially began the transition to barefoot" (Hryvniak. 2014)

Bottom line: Just like most of the more recent experimental evidence the quasi-anecdotal data from the 509 runners Hryvniak et al. surveyed for their latest paper suggest: Running barefoot is safe and effective.

And while it took 45% of the study participants some time to get used to the increased achilles tendon stress + foot pain, Hryvniak. et al. say that "those that did primarily experienced foot and ankle injuries indicating the need to progress slowly so that the new areas of loading can adap"t (Hryvniak. 2014). In conjunction with the reduction of previous injuries after starting barefoot running programs, the result of the survey at hand should thus provide an incentive to try and see how you fare without / with minimal shoes, as well - I mean, what do you have to lose?

References:

• Burkett, L. N., WENDY M. Kohrt, and R. I. C. H. A. R. D. Buchbinder. "Effects of shoes and foot orthotics on VO2 and selected frontal plane knee kinematics." Medicine and Science in Sports and Exercise 17.1 (1985): 158-163. 
• Hryvniak, David, Jay Dicharry, and Robert Wilder. "Barefoot running survey: Evidence from the field." Journal of Sport and Health Science (2014).
• Robbins, Steven E., and Adel M. Hanna. "Running-related injury prevention through barefoot adaptations." Medicine and Science in Sports and Exercise 19.2 (1987): 148-156.

Endurance Athletes Bath in Cortisol: Dose-Dependent Elevations in Hair Cortisol of Triathletes and Runners.

Image 1: There are two types of endurance exercise - the one that is healthy for obese diabetics and the one that chronically stresses and, in the worst case, eventually kills healthy but overambitious hobby athletes; the photo shows a collapsed runner at the 2007 London Marathon, where 22 of his comrades died
(source thisislondon.co.uk)

In view of the fact, that the series of blogposts on High Intensity Interval Training (HIIT) I made in the course of the last weeks were pretty popular, I thought it may also be of interest that there are interesting new results on the effects of resistance training which goes beyond the common "we took 12 obese sedentary post-menopausal women and had them ride a stationary bike for 45min three times a week" approaches, as well. One of these studies happens to come from a group of German scientists from the Universities of Dresden, Marburg and Hamburg (Kirschbaum. 2011); and the results underline my previous comments on the difference between endurance exercise as it is understood by the medical orthodoxy (and as I described it in the previous sentence) and endurance exercise as many hobby athletes and fitness enthusiasts define it. While the former is unquestionably beneficial for obese diabetics or anyone else who would otherwise sit on the couch watch TV and stuff himself with potato chips and ice-cream, 3x45 min of riding a bike probably won't improve the physical condition of a reasonable conditioned hobby athlete. Now, the Kirschbaum study shows quite convincingly that the opposite extreme, i.e. jogging / running and training loads way beyond 40km per week, comes with another certainly more annoying sting in the tail: chronic stress.

In their study, Clemens Kirschbaum et al. analyzed the hair samples of 304 amateur endurance athletes (long-distance runners, triathletes and cyclists; 190 females, 114 males,  mean age ~38 years) and 70  active control subjects (all recruited at local sport events or from friends and family of the authors ;-) and found on average +42% higher hair cortisol concentrations in the endurance athletes.

Figure 1: Relative increase in hair cortisol levels in endurance athletes compared to controls (Kirschbaum. 2011)

As figure 1 goes to show the increase and, more specifically, it's statistical significance largely depended on the type and the duration of exercise. While both cycling and 10k runs increased cortisol levels by about +36%, in this group there were too many "outlayers", i.e. persons with either much higher or much lower cortisol levels, for this increase to reach statistical significance (as defined by a p-value of p<0.05, meaning that chances that this observation happens to be mere coincidence are <5%). In the study participants who stated that they were running half-marathons, triathlons and marathons, on the other hand, the increases in cortisol (+36%, +48% and +66%) were statistically significant, and in case of the marathon runners even dead (consider this a "forerunner" of what may befall marathon junkies) certain.

Figure 2: Relative increase in hair cortisol levels of endurance runners in relation to average weekly training load in kilometers (calculation based on a regression with r=0.32, indicating a below average precision; Kirschbaum. 2011))

If we disregard any reservations concerning the general validity of hair analysis as long-term marker of cortisol levels (recent studies like Manenschijn. 2011 a.o. would suggest that they are valid), Kirschbaum et al. are thusly right to conclude that their data suggests ...

that repeated physical stress of intensive training and competitive races among endurance athletes is associated with elevated cortisol exposure over prolonged periods of time.

Even more important is their advice that, due to the possibly important implications of these findings, it would be necessary to study potentially detrimental effects on the somatic and mental health of the athletes in the future! Well, I probably don't have to tell you that the SuppVersity is going to be the place, where you will read about those studies first ;-)

Tired of Being Obese? Walk Like a Bodybuilder! Study Confirms Effectivity of Incline Treadmill-Walking

Are you obese or just generally concerned about your joint health? Forget jogging and ramp up your treadmill. According to the results of a study published in the latest issue of the Journal of the American College of Sports Medicine (MSSE. 2011) slow walking on an incline produces a similar metabolic workload as running while concomitantly reducing loading rates on lower extremities:

Metabolic rates were similar across trials and were moderate intensity (48.5-59.8% of VO2max). Walking slower uphill significantly reduced loading rates and lower extremity net muscle moments compared to faster level walking. Peak knee extension and adduction moments were reduced by ~ 19% and 26%, respectively, when subjects walked up a 6[degrees] incline at 0.75m/s vs. level walking at 1.50m/s.

So, ramp up your incline and walk, but please do me a favor and do not hold on to the handle in front of you, like some of the overweight mamas at my gym do. This will not only reduce the work-intensity and thus diminish the metabolic effect, it may as well ruin your back.

Edit: Dr. Rouse was kind enough to remind me that there is a world beyond the gym (cf. my Facebook page) and that just walking outside would be a better alternative - thanks Peter ;-)

One Year Aerobic Endurance Training Raises Fat Oxidation During Exercise But Not Resting Metabolic Rate

While doing aerobics on a regular basis is unquestionably healthy, it will not have the same beneficial effects on resting metabolic rate (RMR) as weight training. At least this is what a recent study (Scharhag-Rosenberger. 2010) suggests.

The German scientists observed previously untrained, but healthy subject, who jogged/walked 3 days a week for 45 minutes, over a whole year and recognized positive effects on body composition and rate of fat oxidation during exercise.

Relative contribution of fat and carbohydrate (CHO) oxidation to
RMR (pie chart: means, data: means ± SD, N = 17). (Scharhag-Rosenberger. 2010. Fig.3)

On the other hand cardiovascular exercise failed to provide beneficial effects on the subjects' resting metabolic rate. Thus, if you intend to lose weight and to keep it off, you should complemented your jogging/walking sessions by a concurrent strength training regime. The latter will increase RMR (due to an increase in energy consuming muscle mass) and thus facilitate weight loss and weight management especially after and in the course of a calorie restricted diet.