Association Between Running Shoe Characteristics and Lower Extremity Injuries in United Stated Military Academy Cadets.
Helton GL, Cameron KL, Zifchock RA, Miller E, Goss DL, Song J, Neary MT. Am J Sports Med. 2019 Sept. https://doi.org/10.1177/0363546519870534 [Epub ahead of print]
Text Freely Available
Cadets wearing exercise shoes with a mild-to-moderate rigidity experienced fewer exercise-related injuries when compared to minimal rigidity. Likewise, shoes with a mild to moderate heel height reduced the risk of injury compared to minimal heel heights.
Running is a popular form of physical activity and is the primary form of endurance training among United States military personnel. Running accounts for 50% of all exercise- and sports-related injuries in the Army. It is important for healthcare providers to identify modifiable risk factors for running-related musculoskeletal injuries – such as shoe characteristics – to help prevent these injuries. Specifically, heel height, which provides cushion, and torsional stiffness, which provides flexibility or motion control, are two shoe characteristics that have received little attention regarding the risk of injury. Therefore, the researchers evaluated the relationship between lower extremity injuries and shoes’ heel height or torsional stiffness in U.S. Military Academy Cadets enrolled in basic training. The researchers tested 827 cadets during their first week of basic training and followed them for 9 weeks. Cadets never received standard shoes to wear. Instead, they were instructed to bring “relatively new shoes that have been broken in but not worn out.” The study team measured shoe characteristics with a custom device during the initial testing. The study team assumed these shoes would be worn throughout training. The research team then monitored the cadets for injuries, which they defined as occurring during basic training and resulting in at least 3 days of limited physical activity. Further, they defined an overuse injury as those with a gradual onset secondary to running or marching (repetitive microtrauma). Baseline data also included age, sex, height, body mass index, ethnicity, injury history, foot strike pattern, and foot posture index. The authors divided each shoe characteristic into minimal, mild, moderate, and extreme ranges. Further, torsional stiffness was broken down into medial and lateral rotations.
The researchers reported that about 18% of cadets had a lower extremity injury, and most (59%) were chronic in nature. Neither foot strike pattern nor foot posture index related to injury onset. Cadets wearing shoes with moderate lateral-torsional stiffness were ~50% less likely to incur any lower extremity injury or an overuse injury compared to those wearing shoes with minimal lateral-torsional stiffness. Further, individuals wearing mild or extreme lateral torsion were about 40% less likely to sustain an injury compared to those wearing shoes with minimal stiffness. Similarly, shoes with a mild or moderate heel height were 51% and 40%, respectively, less likely to sustain an injury compared to those wearing shoes with minimal heel height. No other shoe characteristics related to injury risk.
The authors of this study recommended that military cadets reporting for basic training should wear shoes with a mild to moderate lateral-torsional stiffness with an appropriate heel height (2.2 to 2.8 cm) to prevent injuries that are sustained during running or marching. Basic training performed by military cadets is a unique form of training and therefore requires a unique standard for shoe characteristics. Furthermore, the claim that mild to moderate torsional stiffness and moderate heel height reduce injury risk in cadets may not be applicable to most runners. Although the results of this study are highly promising, an underlying shoe characteristic that should not be ignored is the individual’s comfort. Heel height, motion control, and durability are all important in reducing impact forces and plantar pressures. The current recommendation is to find a shoe in between the extremes of torsional stiffness and heel height. The reported shoe characteristics in this study fall in between the minimalist and maximalist thresholds and the authors recommend advising patients in training environments like the military to avoid the extreme ends of lateral-torsional stiffness and heel height.
Questions for Discussion
Do you provide running shoe recommendations to all of your patients, or only those with a current or previous injury? What is the most important running shoe characteristics to consider when providing a recommendation to your patients?
Written by: Danielle M. Torp
Reviewed by: Jeffrey Driban
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This blog is very interesting. I can relate only because I am a current athlete and I’ve experienced such injury from my shoes and the surfaces I have been running on. First, I do recommend running shoe recommendations to all my patients and my previous athletes that had a current or previous injury. As a runner, it’s always one of the first things I look at on any athlete when they have lower extremity concerns or injuries. But currently I am at a PT clinic for clinical and so when some of my patients come in and they don’t have the proper shoes for their rehab, I tend to get worried. Only because for one specific patient I have, I have made his program and so I have added agility in which he has to cut a certain way, hop, etc. Today he was doing new agility and kept sliding due to his footwear. It was concerning because I didn’t want him to reinjure himself. And so, when it comes to running shoes, one of the most important characteristics that I consider when recommending a shoe to my patient/ athlete are the soles of the shoes. Whether if the rubber is stripped away, has holes at the bottom, or even worn out meaning more than a 1 year old. When explaining the type of running shoe one should have, I always explain to them about the bottom. Making sure they know not to get a shoe with a flat sole but curved, purchase a shoe with a groove rubber sole. That’ll mean that the shoes are light weight and its cushioned and flexible. But in all, like the text stated, it all depends because some may do well with a shoe with a heel height and also the way the patients/athletes foot posture and foot strike are. Whether it could be a long-distance runner, sprinter, or even mid distance for example. Good running shoes will help prevent injuries such as medial tibial stress syndrome.
Thank you for the comment. I am pleased to hear you take into consideration shoe characteristics with your patients. One comment you made regarding the bottom of the sole and it’s age, it is important to remember that the milage put into shoes is more important than the actual age. However, I agree with your observation that if the soles are worn down they need to be replaced. There is plenty of research available for shoe characteristic recommendations and previous injury history- make sure to take into account different aspects for different patient populations.
I was immediately attracted to this article being a runner, ATS, and military brat. I was intrigued to find out more and what route the article would take. As a runner and ATS I was interested in the entire message, because I believed it could apply to not only military personnel, but to athletes and the general population.
I found this research very necessary although this particular study focuses on the military, I think that it could apply to everyone, because so many people utilize running whether it be in their exercise routine or profession. Prior to this reading I was unaware that torsional stiffness had minimal amount of research on risk of injury, because to me it already seems like such an important factor — being that it allows for flexibility and motion control. Heel height was also a surprising factor that I didn’t know could correlate with risk of injury, because I had never thought about that before. The findings from the study make sense to me, seeing that moderate torsional stiffness in shoes rendered less injuries, while heel height is a bit tricky for me because “2.2-2.8 cm” doesn’t seem like much. In my experience as a runner, I have never fully paid attention the specifics of my shoes other than how I feel in them, if they fit properly, and how comfortable they are. And in my experience so far as an ATS, I have seen throughout clinical that athletic trainers actually look at and study athletes’ shoes, strike pattern, and posture to fully get a sense as to what could be the factor playing into their injury/discomfort. I have seen them recommend shoes as well, but this reading brought awareness to the prevention aspect as well, as to go on and even recommend shoes to athletes/patients who aren’t even injured. Personally, I would recommend shoes that feel comfortable, but also supportive, because that’s also what has worked for me.
Overall I think this research is needed, and I am also glad to see our field concerned with not only athletes but also the well-being of ones of protect us everyday.
Thank you for your comment, I am glad you enjoyed this post. I agree with your current thinking regarding shoe recommendations- find shoes that fit well and feel good. I think the athletic trainers you are working with are doing a great job in assessing the shoe as a whole and the needs of the patient. Shoe characteristics should be very individualized, but this specific research article does point to some general characteristics that may help those who are at risk for injuries simply by their athletic status. I hope you continue to consider shoe characteristics in your future professional settings.
Thank you, Danielle
I am glad I came across this article. I can relate to the topic, being a retired running athlete I know the importance of maintaining you shoe characteristics. I suffered from chronic shin splits, plantar flaciitis, and tendinitis in my extensors of the foot all due to improper footwear. Also being an ATC student and going to my clinical site which is at a D3 college I see numerous injuries relating to this topic. Younger athletes tend to practice in worn out footwear often and end up with shin splits or other lower injuries and by the end of their season some are unable to compete because of it. I dont provide shoe recommendations unless the athlete has had reoccurring or occurring injuries due to footwear. Sometimes it’s hard to avoid or differentiate lower foot or lower leg injuries just from the shoes it can also be surface issues, improper foot placements, running gate, and landing. If I had the chance to recommend before participation I would recommend the appropriate heel height being 2.5cm and depending on the athletes arch height I’ll determine what the later-torsional stiffness should be. One thing I would recommend to someone with severe chronic injuries is seeing a specialist in foot or footwear to determine the most appropriate shoe.
Thank you for the comment and insight. I particularly like your thinking about injuries onset being influenced by more than just shoe characteristics- surface, cumulative load, gait kinematics, and a plethora of other factors. Recent studies are looking at the number of hours of sleep and the risk of injury. However, based on this article, it would suggest shoe characteristics play some role in injury prevention. In my experience, the younger athletes aren’t as knowledgable in proper shoe wear and thus as athletic trainers, this is where we should intervene and educate our patients on the importance of injury prevention, especially an easy/small fix like proper shoes.
Thank you, Danielle
I believe that this is a very intriguing topic to be reviewed in the clinical setting. I am a current AT student at a high school, every other day we have another runner that comes in with complaints of pain either in the shin or foot region. It is an easy assumption that running with improper footwear is a risk for a lower extremity injury. In the study, it was stated that cadets had a lower risk of injury when wearing shoes that are more rigid and also shoes with a higher heel height. Another thing I would be interested in looking at is the arch of the cadets foot and if they are flat footed or have a functional flat foot versus an arch. At the high school I am working at, we asses the athletes mechanics, gait, and shoes worn upon complaint of injury. We have almost eradicated all shin splint injures with providing an arch support for the athletes that have a flat foot or a navicular drop. One thing I would be cautious about raising the heel in a cadets shoe is increasing the risk of stress fractures in the metatarsals.
Like previously mentioned I believe this is a very important topic when assessing a lower extremity injury. Different shoes and surfaces can have a greater impact on a patient and can create more chronic injuries if left untreated. I am currently an AT student and it is interesting to see what different athletic trainers take into account when they are assessing someone’s gait and lower extremity injuries. At my most recent site the head athletic trainer was big on making sure the athletes were wearing proper shoes not just while they were running to reduce their injuries. Lower extremity injuries are relatively common and I think running shoe recommendations are important but also think it is important to take the athletes gait and arches into consideration. I think looking at a patients foot strike pattern is the most important when determining what type of running shoe would fit best. Additionally I also think it is important to note how old the shoes are to determine how much wear and tear has already been done to the shoe. I like how this study had the participants wear shoes that were broken in but also not worn out. We see athletes sometimes cling onto their shoes which can also create more issues.
This post highlights a lot of newer concerns I have had working with athletes and their struggle with shoe selection. I was always curious about the connection between footwear, gait and even various loads and its effect on lower extremity injury. I noticed a lot of injuries happening with those who not only bared more weight but were wearing older shoes that did not support their high or low arches. I also noticed the rise in injuries based on the design of certain new released shoes and I am just curious about what we can do with limited resources clinically? As a student at previous clinical rotations, I would have access to athlete’s gait and posture analyses and have foot pressure measurements from preseason to help us decide come up with conditioning programs and create custom orthotics. Just like with these past sites I agree with Rachel, I would hope there is more focus on shoes and a consideration of the surfaces, regardless of the population so we can reduce these chronic lower extremity injuries.