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