Toe Spring And Plantar Fasciitis

Ever wonder why so many people other than runners are getting plantar fasciitis? It may be because of the amount of 'toe spring' in your shoes.

You may have already noticed this in your running (or other) shoes, most of them seem to have 'toe spring'. Toe spring is how much the front of the shoe is curved upwards. This curve allows your foot to roll off the front of your foot more easily compared to wearing flatter soled shoes.

Hence, the toe spring allow your foot muscles to work less hard when you are walking or running. The more toe spring in the shoe, the less work your feet have to do.

However, this may lead to weaker foot muscles according to research (Sichting et al, 2020).Weaker intrinsic foot muscles may increase your chances of sustaining injuries like plantar fasciitis.

In the research which includes famed Harvard evolutionary biologist / barefoot running researcher, Daniel Lieberman, had subjects walk on a specially designed treadmill that had force plates and infrared cameras to measure how much power was put into each step.

The subjects walked barefoot in four different pairs of custom made sandals. The sandals had varying angles of toe spring from 10 to 40 degrees. These ranges of curvatures were designed to be similar to modern footwear.

Sandals were chosen as they allowed the researchers to see the exact motion of the subjects' feet as they walked. The different degrees of toe spring can be filmed to see how they affected their gait with special attention paid to the metatarsophalangeal (MTP) joints at the base of their toes. This is where the toe bones join to the foot bones.

The results showed that the more the shoes curved up front, the less propulsive force was generated with their MTP joints. This means that your intrinsic foot muscles are working less to maintain stability when you move making walking and running easier. However, it also decondition your foot muscles over time, making them weaker and not able to protect other structures in your foot.

Weaker intrinsic foot muscles make one more susceptible to conditions like plantar fasciitis as people rely on their plantar fascia to do what the intrinsic muscles normally do. This may also explain why people get injured if they transition too quickly minimalist type barefoot style running shoes.

Many of my patients who do not run with plantar fasciitis have been told to wear more 'supportive' and comfortable shoes while outside or even at home. This may be worse as their intrinsic foot muscles continue to weaken.

This is why shoes with more toe spring are popular because they are more comfortable and prevent your feet from tiring. This is great in a race and it may be why most racing shoes have a lot of toe spring (see picture below).

More research needs to be done with toe spring and foot injuries as other elements of footwear like stiffer soles and amount of cushioning can impact how our intrinsic foot muscles work.

So what should a runner do? Some physiotherapists and podiatrists often suggest doing intrinsic foot exercises like towel scrunching or pulling your toes toward your heel.

I suggest going barefoot more often. Either at the beach, or when you're at the playground with your kids. In Singapore we are generally barefoot while we're at home. That's better than wearing shoes with lots of toe spring at home. 

While training, look for running shoes with little or no toe spring when you train. 

For my patients who have plantar fasciitis, I tell them to wear flat slippers like Havaianas to minimize the effect of toe spring and for their intrinsic foot muscles to get stronger. 

That is totally different from what some other physiotherapists or podiatrists may suggest. Of course, I also treat plantar fasciitis differently from them.

Reference

Sichting F, Holowka NB, Hansen OB and Lieberman DE (2020). Effect Of The Upward Curvature Of Toe Springs On Walking Humans. Sci Reports 10, 14643. DOI: 10.1038/s441598-020-71247-9.

Asics Metaracer Tokyo - a racing shoe with lots of toe spring

Are You Choosing Running Shoes Based On Comfort?

Picture by Oyvind Solstad from Flickr

Don't we all love shoes that are comfortable? Especially when it comes to our running shoes. As runners, we all love that ahhhh sensation of our first steps in an exceptionally soft and comfy shoe. I couldn't believe how soft an Adidas NMD (not really running shoe though) felt when I first slipped it on. 

A more comfortable (or cushioned) shoe is usually preferred by new runners or for runners who are prone to injury and want extra protection and support.

The shoe companies know that subjective comfort is an essential factor in sport shoe development since this definitely helps them sell shoes. This comfort paradigm is based on an assumption that perceived comfort will lead to a path of least resistance (while running) and potentially reduce injury and improve running economy. (Luo et al 2009; Mundermann et al, 2001).

We've definitely been sold on advertisements selling us the softest, bounciest and energy return shoes that propel us forward and saves us energy and prevent injuries.

One study showed reduced oxygen consumption levels during running at submaximal speed while running in shoes that were rated subjectively as most comfortable (Luo et al, 2009). This may support the fact that running economy improves due to reduction of muscle activation (which decreases oxygen consumption or metabolic demand). 

Another study on military personnel showed some evidence supporting the use of comfortable shoe inserts (or orthotics) reduced injury rates of the foot, ankle, hip, knee and lower back compared to a control group.  However, two studies are not credible enough to know what actually helps and what are the mechanisms of reduction in oxygen consumption and preventing injuries. (Both studies count Professor of Biomechanics Benno Nigg, known for his work of running shoes as one of the authors).

In this latest paper I read, the authors aimed to investigate how shoes of differing comfort affects differences in oxygen demand along with potential mechanisms associated with injury risk. 

Fifteen male runners who ran at least 20 km per week with treadmill experience were recruited for the study. Testing includes an incremental lactate threshold test, a comfort assessment and treadmill running trials for biomechanical and physiological assessments. 

The researchers did not find any decrease in oxygen consumption in the most preferred shoe. Potential biomechanical contributors to changes in oxygen consumption (or metabolic demand) showed some differences in stride rate between the most preferred and least preferred shoe. Personally, it was interesting for me to note that stride frequency was actually lower in the most preferred (or comfortable) shoe compared to the least preferred (or least comfortable).

Based on the findings of this study, previous suggestions (derived from two other studies) regarding positive effects of enhanced footwear comfort during running cannot be supported. Neither on running economy nor on preventing injuries.

Should we then choose our running shoes based on comfort alone? This study suggest maybe not since the most comfortable shoes were not better or worse off with regards to oxygen consumption and not enough data to show any real change on injury risk.

Comfort is just one of many factors when we choose running shoes (compared to the more common foot type option like overpronators, supinators etc). Of course I definitely would not suggest running in shoes that are uncomfortable. 

I'm also feeling appalled that only 15 male runners (and no female  runners) were selected for the study. Remember I write previously how difficult it is to recruit runners to participate in a running research.

Athletes will want shoes that give them absolute efficiency that helps that run faster while your average runner would want the least discomfort while running to get fit.  

Of course there are some runners that will choose based on colour! *facepalm*

References

Lindorfer J, Kroll J and Schwameder H (2019). Does Enhanced Footwear Comfort Affect Oxygen And Running Biomechanics? Eur J Sport Sci. 20(4): 468-476. DOI : 10.1080/17461391.2019.164028

Luo, G, Stergiou P et al (2009). Improved Footwear Comfort Reduces Oxygen Consumption During Running. Footwear Sci. 1(1): 25-29. DOI: 10.1080/194242809002993001

Mundermann A, Stefanyshyn DJ and Nigg BM et al (2001). Relationship Between Footwear Comfort of Shoe Inserts and Anthropometric And Sensory Factors. Med Sci Sport Ex. 33(11): 1939-1945. DOI: 10.1097/00005768-200111000-00021.

Notes on the shoes in this study provided by Adidas

Five different shoes based on criteria previously reported in another study (Luo et al, 2009) were provided for this study. The shoe conditions showed variations in total mass (80 grams), heel lift (3.7mm), forefoot cushioning, rearfoot cushioning forefoot bending and rearfoot bending. The shoes in this study includes a standard neutral running shoe, shoes equipped with non standardized features like carbon fiber plates for increased longitudinal bending stiffness, exaggerated arch support and a cross training shoe.

One interesting point was that the researchers glued lead to the heel counters of the shoes that were lighter (since shoe mass influences oxygen consumption by about 1% per 100 grams of additional mass).

Physical Activity Decreases Your Risk Of Colorectal Cancer

Group ride on 090219 - definitely miss those rides

I was very active in primary school. Other than swimming occasionally and playing police and thief (running), I also played football, basketball, table tennis and badminton. It was only in secondary school that I started to be more serious with cross country running and athletics.

How about you? Try to recall what you were doing as a teenager. A recent study suggest that how active you were back then and and how you've maintained it till now is important when gauging your risk of colorectal cancer.

Physical activity during adolescence helps lower risk of colorectal cancer. If you have been able to continue daily moderate physical exercise well into adulthood, the results are even better.

The study showed that those who did at least an hour of physical activity daily from 12 to 22 years had a reduced risk of adenoma (polyps or a benign tumor formed from glandular tissue) by 7 percent compared to those who were less active. (Polyps are considered a precursor of colorectal cancer).

Those who started physical activity as adults reduced risk by 9 percent. However, those are were active as teens and continued being active for at least an hour as adults reduced their adenoma risk by 24 percent!

The researchers analysed the data of 28,250 female subjects aged 25 to 42. Physical activity, nutrition, hormones were among some of the data studied.

The researchers suggest that being physically active reduces the risk of colorectal cancer since it helps weight management and control and thereby affects insulin resistance and inflammation as they are involved in promotion and progression of cancer.

I would be very interested if the researchers measured how intense or hard the physical activities were. And how often were these higher intensity sessions and whether they made any difference.

However, this study did not analyse that. The authors did mentioned that previous studies have shown that moderate to vigorous activities were associated with lower bowel, breast and endometrium cancers.

Take home message is that there is a cumulative effect of physical activity as we grow older. Even if you have been inactive as a child, it is not too late to start now. And the longer you maintain that physical activity, the better off you'll be.


Reference

Rezande L, Lee DH, Keum N et al, (2019). Physical Activity During Adolescence And Risk Of Colorectal Adenoma Later In Life: Results From The Nurses' Health Study II. Br J Cancer. 121: 86-94. DOI: 10.1038/s41416-019-0454-1.

Picture above taken yesterday by Dennis Thong. I still try to be as active as possible daily with at least one complete rest day a week.

You should too.

What is More Helpful Than Electrolytes In Preventing Muscle Cramps?

I don't believe this. Many athletes still do not know what causes muscle cramps. In a survey of 344 endurance athletes published last year, 75 percent believed that taking extra sodium would help prevent their muscles cramping (McCubbin et al, 2019).

The usual and common theories for muscle cramps are loss of electrolytes (sodium, potassium and magnesium) and dehydration (fluid). Suggestions to combat cramps are to eat more bananas, take more salt/ sodium, magnesium supplementation, drink Gatorade etc. None of which will really help.

Having written on muscle cramps a few times, I'm most interested when new research suggests alternative ways to beat muscle cramping.

The researchers (Martinez-Navarro et al, 2020) recruited 98 runners running the Valencia marathon of which 84 (72 males, 12 females) completed the study (all pre and post race testing). 

20 runners suffered muscle cramps during or immediately after the race. Blood and urine tests showed no differences in dehydration and electrolyte levels before, during and after the race for the runners that cramped versus those that did not.

What the researchers found was a big difference in creatine kinase and lactate dehydrogenase which are both markers of muscle damage. These markers were significantly elevated immediately post race and 24 hours in those runners who had cramps.

There was also no difference when the runners did their last training run prior to the race nor any sign of elevated muscle damage in pre race tests. Hence, the runners who cramped did not have any muscle damage (from not tapering/ resting or backing off from training). 

Almost all the training variables between the two groups were similar. Weekly mileage, previous marathons ran, etc were all similar save one variable. 48 percent of those who did not suffer from cramps did regular lower body strength training compared to 25 percent of those who cramped.

This adds more weight to my previous post that muscle cramps are more likely to occur in muscles that are tired/ fatigued to the point of damage.

I would like to add that dehydration and electrolyte depletion can hasten muscular fatigue which then causes muscle cramping.

If you're still struggling with muscle cramps, it's definitely worth giving lower limb strength training a shot and for it's other benefits as well. 

Another researcher (Del Cosco et al, 2013)who wrote about muscle damage causing one to slow down at the end of marathons suggested lower limb exercises up to 80 percent maximum weight you can lift to protect your legs from damage.

References 

Del Cosco J,  Fernandez D, Abian-Vicen J et al (2013). Running Pace Decrease During A Marathon Is Positivively Related To Blood Markers Of Muscle Damage. PLoS One. 8(2): e57602. DOI: 10.1371/journal.pone.0057602

Martinez-Navarro I, Montoya-Vieco A et al (2020). Muscle Cramping In The Marathon: Dehydration And Electrolyte Depletion Vs Muscle Damage. J Stren Cond Res. DOI: 10.1519/JSC.0000000000003713.

McCubbin AJ, Cox GR et al (2019). Sodium Intake Beliefs, Information Sources, And Intended Practices Of Endurance Athletes Before And During Exercise. Int J Sp Nutr Ex Metab. 29(4): 371-381. DOI: 10.1123/jisnem.2018-0270.