What Causes Running Injuries?

Navicular drop from Physiopedia

Recently we have seen more runners coming to see us in our clinics. A few are preparing for the Berlin marathon next month while others are preparing for ultras and the local Stan Chart marathon later in the year. What was common is their lack of gluteus medius strength, sudden increase in training load, change in running shoes amd not enough recovery.

How did my observation compare to a published research on factors associated with running related injuries? This group of researchers aimed to identify factors associated with running related injuries and also to evaluate their potential in injury screening.

274 recreational runners were recruited for their study. At baseline, running technique, clinical measures (strength, range of motion (ROM), foot position), impact loading, injury and training history were collected. These runners were followed up fortnightly for 1 year.

49 runners dropped out leaving 225 (84 females, 141 males) for the final analysis. 52 percent experienced a running related injury. Calf strain (15 percent), Achilles tendon injury (11 percent) and plantar fasciitis (9 percent) made up the largest proportion of injuries.

After adjusting for age, weekly mileage and sex, the following factors were statistically significant and associated with increased likelihood of injury. Previous injuries in the past year, less navicular drop, weaker hamstrings and measures of running technique (knee, hip and pelvis kinematics) were associated with increased likelihood of injury.

There were significant associations between running injuries and hip and knee kinematics like contralateral (opposite side) pelvic drop and increased knee inward rotation. All of which I have written about before in a previous post.

I was surprised that the calf constituted the highest proportion of injuries. I (falsely) assumed the knee would be the most common site of injury. Perhaps popularity in adopting forefoot and midfoot running styles (which takes load away from the knees but transfer them to the calf, ankle and Achilles) compared to heel striking which loads the knee more. 

Another study found shin splints and stress fractures followed by Achilles tendon injuries to be the most common diagnosis in recreational runners (Mulvad et al 2018).

Only the navicular drop test (not strength, ROM, foot positioning among the clinical measurements) was associated with injury. The navicular drop is a measurement of how much the navicular bone moves from a neutral sitting position to standing. The larger the movement, the larger the collapse of the arch of the foot. 

The researches found that the less navicular drop, the higher the chances of injury, a navicular drop <10mm increased injury odds by 2 times. Values of the navicular drop test in this study would place the uninjured runners in the "pronated" foot category and the injured runners in the "neutral" foot category.  

The researchers explained that uninjured runners may have a more flexible foot with increased capacity to absorb loads. This supports emerging evidence that flat feet may be protective in nature as compared to previous views that flat feet needs 'support'. 

One of my often copied Shoe Lists update

For years, podiatrists, coaches and shoe salesmen have looked at your foot type (to see if you have normal, low or high arches) (pictured above), then recommended that you have stability, motion control and cushioned shoes respectively. The rationale being that if you had high arches, you did not pronate enough and needed softer, well cushioned shoes while if you had low arches, you tend to overpronate and needed sturdy motion control shoes to control that overpronation. Runners with normal arches needed neutral shoes and were prescribed stability shoes. This method was deeply rooted in athletic circles and widely accepted. Time to bin that permanently.

 Also relate this to wearing orthotics. Patients are to told that orthotics help prevent the arch from "collapsing". This study shows that if the arch does not collapse (or drop) more than 10 mm,  you are twice as likely to get a running injury. Something to mull over for runners who have been told to wear orthotics. We (sports doctors, physiotherapists, podiatrists etc) MUST definitely reconsider running injury prevention and treatment techniques aimed at correcting 'overpronation' since there is no association between foot eversion (pronation) and running injuries in this study.

Previous injuries less than a year ago was a strong predictor of getting injured again. This may indicate that some runners have not regained original tissue strength or they have alterations in technique that increase their vulnerability to injury. 

References

Dillon S, Burke A, Whyte EF et al (2023). Running Towards Injury? A Prospective Investigation Of Factors Associated With Running Injuries. PLoS One. 18(8): e0288814. DOI: 10.1371/journal.pone.0288814

Mulvad B, Nielsen R, Ling M et al (2018). Diagnoses And Time To Recovery Among Recreational Runners In The RUN CLEVER Trial. PLoS One. 13(10). pmd:30312310. DOI: 10.1371/journal.pone.0204742

No Need To Treat Your Child's Flat Feet

My young patient (only 6 years young then) was told he had flat feet, pronated 'too much' and needed orthotics. He was prescribed the pair of ankle foot orthoses pictured below. His parents ended up a few thousand dollars poorer and they were told to bring him back for more appointments. 

I could not begin to imagine the trauma this child had to go through mentally and physically, having had to wear those *orthotics (picture below) whenever he went out.

Parents with children who have flat feet please take note. This latest Cochrane Review (just published on 14/1/22) states that "in the absence of pain, the use of high cost customised foot orthoses (CFO) for healthy children (from 11 months to 19 years old) with flexible flat feet has NO supporting evidence, and draws very limited conclusions about foot orthoses for treating paediatric flat feet". 

Review articles from the Cochrane Database of Systematic Reviews are highly respected and trusted. Google it if you like.

Not just costly CFO's, less expensive prefabricated (off the shelf) foot orthoses are not needed as well.

This Cochrane review also suggests that there is no further need to research asymptomatic flat feet in healthy children. It is better to focus on other paediatric conditions instead. 

Parents, now you know, do not waste your time and hard earned money on orthotics for your children. Don't worry too much about their shoes too. Email me if you want a copy of the article.

Reference

Evans AM, Rome K, Carroll M et al (2022). Foot Orthoses For Treating Paediatric Flat Feet. Cochrane Database of Systematic Reviews. Issue 1. Art No: CD006311. DOI: 10.1002/14651858.CD006311.pub3. Accessed 18 January 2022

*in my opinion, the orthotics look like they will do a better job limiting ankle movement with the stiff upright medial (inner) and lateral (outer) sections

Towel Scrunching Exercises For Your Feet?

Have you ever been asked to do foot strengthening exercises? A patient who saw me this week was asked to do foot strengthening exercises by another health professional who saw him recently. This included some towel scrunching exercises for his "collapsed arches" so as to strengthen the muscles supporting his arches. 

My patient was quickly bored and I told him just walking in minimalist footwear would be just as effective as doing strengthening exercises for the foot.

We know from published evidence that weakness in our intrinsic foot muscles can lead to a variety of load related injuries. And supportive footwear can contribute to intrinsic foot muscle weakness since these muscles tend to switch off (since they aren't absorbing forces and controlling foot movement) while walking and running.

Researches randomly assigned runners into three different groups. One group wore minimialist shoes (Vivo Barefoot), another group did foot strengthening exercises and the third was a control group. All groups maintained their running mileage throughout the study.

The minimialist footwear group increased their walking step count weekly while the foot exercise group did progressive resistance exercises at least 5 days per week.

Foot muscle strength and size were measured via ultrasound at the start of the study, week 4 and at the end of  the study (week 8). Researchers found all foot muscle sizes and strength had increased significantly in both the minimalist footwear and foot strengthening exercise group. There were no changes in the control group.

The researchers concluded that walking in minimialist shoes is just as effective as doing strengthening exercises for your feet. It is definitely way more convenient changing footwear rather than doing specific foot exercises. This may result in better compliance with patients.

So definitely don't throw away your Vibrams or barefoot style/ minimialist type shoes. They are definitely still useful. Vibram ended up with a bad reputation after they were sued. 

However, I feel minimalist type shoes were unfairly criticized as the evidence for barefoot or minimalist type shoes are actually sound provided your running technique is correct. 

*Much less impact if technique is correct-see below

If you walk with barefoot style/ minimalist type shoes instead or running (to strengthen your intrinsic foot muscles) there will be a much lower risk of injury.

Definitely still useful. And much less boring than doing towel scrunches.

Reference

Ridge S, Olsen M et al (2019). Walking In Minimalist Shoes Is Effective For Strengthening Foot Muscles. 51(1): 104-113. DOI: 10.1249/MSS.0000000000001751.

Liberman DE, Venkadesan M et al (2010). Foot Strike Patterns And Collision Forces In Habitually Barefoot Versus Shod Runners. Nature. Jan 463(7280): 531-535.

*Using results of Daniel Liberman's study, runners who land correctly in their running technique will have benefits as impact is a LOT less (even less than heel striking with cushioned running shoes). If you land wrongly (with barefoot style shoes), the impact is 7 times greater thus greatly increasing the chance of injury. See picture above.

Do High Tech Running Shoes Work?

All you readers out there be ready for some shocking news from a study published in the latest issue of the British Journal Of Sports Medicine. I think all the shoe companies out there will not be too impressed with this paper with regards to their technical running shoes.

The researchers reviewed results since 1950 from controlled clinical trials and systematic reviews (the two highest levels in terms of quality with regards to research papers).

Their aim - to investigate if running shoes with highly cushioned heels or pronation controlled systems depending on the wearers foot type had any effect on running injury rates, risk of osteoarthritis, overall well being and of course running performance.

First let's review some background information. American Frank Shorter won the marathon Olympic gold medal on September 10, 1972. It is believed that his victory ushered the start of the American running boom where millions of Americans took up running leading to a huge surge in running shoes being sold. This of course led to an explosion of a vast shoe industry.

Since the 1980's, the heels of running shoes are heavily cushioned and/or have features to control subtalar joint (also known as talocalcaneal joint; where the talus meet the calcaneus) motion. Prescribing such shoes along with orthotics are considered the gold standard for injury prevention. Depending on your foot type, overpronators, mild pronators and supinators are prescribed motion control, stability and cushioned shoes respectively.

The use of cushioning in running shoes are based on the following assumptions (1) impact forces while running is a significant cause of injury. (2) running on hard surfaces causes high impact forces. (3) a cushioned shoe reduces impact forces. (4) cushioning itself to cause injury is minimal.

Evidenced based facts (1) weak evidence to show that running on hard surfaces increases impact forces or injury rates. (2) weak or poor evidence to show that cushioning reduces impact forces or injury rates. (3) diminished proprioception (joint position sense) is a significant side effect of heavily cushioned shoes. (4) reduced ability to monitor impact and foot position carries a significant risk of harm.

Assumptions based on the use of pronation control systems (or motion control shoes) (1) helps to normalize subtalar joint motion in the foot. (2) overpronation linked to overuse injuries. (3) limiting pronation will minimize this risk of overuse injuries. (4) montion control shoes are effective in reducing injuries via this approach.

The evidenced based facts (1) subtalar joint motion or foot types are not consistently associated with runners' injury rates. (2) both motion control and cushioning shoes are relatively ineffective and unreliable in changing subtalar joint motion. (3) both motion control and cushioning shoes causes both small and inconsistent changes in subtalar joint alignment.

In addition it is suggested by shoe companies that raising the heel of a running shoe can minimize Achilles tendon strain and thus reduce Achilles tendon injuries. However the researchers found mixed results with this. In fact since the introduction of shoes with cushioned heels and pronation controlled systems, there has been in increase in Achilles tendon injuries rather a reduction.

Evidence also shows that foot placement on ground with the heel elevated causes the foot to be in a position of poor proprioception (or joint position sense). Read increase in injury as a result. Current levels of heel height in running shoes also been noted to increase pronation.

The researchers found no proof that high-tech running shoes reduce running injury rates, risk of osteoarthritis and overall well being. What about improving running performance? None as well!

The researchers mentioned that sports medicine professionals and not advertising was to blame for this myth regarding high tech running shoes. Why you may wonder? Sports Medicine Australia (SMA), the New Zealand Society of Podiatrists (PNZ) and the International Federation of Sports Medicine (FIMS) all have been endorsing shoes by ASICS despite no credible evidence was the reason given by the researchers. Also mentioned, these footwear recommendations made by SMA, PNZ and FIMS are as part of sponsorship arrangements with ASICS.

Well, here you go, not quite what you expected I'm sure. In my next post, I will discuss what we at Physio and Sports Solutions have been doing with regards to running for the past two years. Yes, we have actually not done what others have been doing with regards to running and running shoe selection. Now we have the evidence to back us up as well. Stay tuned.

Please email me if you want this article.

Reference
CE Richards, PJ Magnin and R Callister. (2009). Is Your Prescription Of Distance Running Shoe Evidenced Based. British Journal Of Sports Medicine. 43(3) pg 159-162.