Running Injury Prevention: Start by Strengthening Foot Muscles
Running related injuries are frustratingly common. A new study suggests foot strengthening—from the ground up—could be the answer.
Of the three events comprising a triathlon, running takes the biggest toll on the body. Every year, as many as 4 in 5 distance runners will sustain some type of running related injury (RRI) that can necessitate a cessation of training efforts. While triathletes are fortunate to be able to use that time to focus on the swim and bike, dedicated runners must stop their training completely and this can lead to significant frustration.
All manner of preventive strategies have been suggested over the years to help runners avoid injury but most haven’t proven helpful in this regard. In numerous studies, none of the proper warm-up or cool-down or stretching exercises have been shown to significantly reduce injuries. Even commonly accepted run training strategies, such as gradually increasing volume, have not been consistently shown to prevent RRIs.
Many have suggested strength training, specifically of the muscles around the hip and knees, as a means of RRI prevention but while there is data to show that this training can improve running performance, the notion that it prevents injury had not yet been definitively proven.
A recent article in the American Journal of Sports Medicine may be the first to show that strength training really does decrease RRI. In this study from Brazil, Dr. Isabel Sacco and her co-investigators reported on the findings of an experiment in which runners were divided in to two groups. The experimental group performed a series of exercises meant to strengthen the intrinsic muscles of the feet while the control group performed stretching exercises and served as a control.
Over twelve months, Sacco followed these runners carefully monitoring their adherence to the strength plan and recording various aspects of their training, including what kinds of shoes they ran in, what surface they ran on, and how much mileage they ran per week and at what pace they did so.
The exercise protocol itself was performed three times per week and took around twenty minutes to complete. Exercises ranged from calf raises to manual massage of the sole of the foot to the very Christmas appropriate ‘making fists with your toes’ and various other techniques.
Sacco and her colleagues measured the participants foot strength by having participants press their big toe forcefully against a pressure plate and by assessing their Foot Posture Index, a clinically accepted measure of intrinsic foot muscle strength.
Over the period of the study, subjects who were randomized to the foot strengthening protocol developed significantly stronger intrinsic foot muscles than did those in the control group, as would be expected. The experimental group was also found to be much less likely to develop running related injuries than the control group. Over the year that subjects were followed, those in the control group were more than twice as likely to develop an injury as those in the experimental group despite running the same volume at the same pace on similar surfaces and in similar running wear.
Another interesting finding was that those in the experimental group developed injuries later than those in the control group and that foot strength correlated with time to injury. That is to say that the higher the foot strength, the longer the time to injury development.
The benefits of foot strength only really became apparent after around four months of study participation suggesting that it took this long for the effects of the strength protocol to work.
“We did not expect an immediate effect after the intervention (foot strengthening protocol), since we did not train the participants to use their newly acquired foot strength at the task of running specifically. Hence, it was expected that each participant would benefit from muscle strengthening at a different point in time, if ever,” said Dr. Sacco.
This study is particularly interesting because it demonstrates such a profound benefit from strengthening such a small group of muscles that are frequently neglected. Dr. Sacco told me: “The ground-up approach seemed to be efficient in reducing proximal running related injuries, especially in the knee area. That said, we do not by any means disregard the importance of training the hip and knee muscles. In 2012 Goldmann and Bruggeman investigated the effects of strengthening the big toe flexors on the kinetics of the foot and ankle during walking, running, and vertical jumping among university athletes. They observed a significant increase in the performance of vertical jumping and extensor and flexor momentum of the metatarsal-phalangeal joint and a gain of 60% to 70% in the strength of the foot. This study showed that the strengthening of these muscles resulted in global kinematic and kinetic alterations.”
In other words, the finding that strengthening the foot alone has profound effects on the kinetic chain of the entire leg is not only unsurprising but somewhat expected.
Sacco further theorized that the rationale behind this ground-up strategy of injury prevention has its underpinning in the basic kinematics of running. If the foot muscles are insufficiently strong, runners may compensate by employing significant amounts of knee excursion or work to avoid overloading the structures of the ankle and foot. Doing so can stress and injure the tendons and muscles and even the joint itself over time. “A foot with stronger muscles and tendons could be better prepared to dissipate this load” and better protect the more proximal larger joint of the knee she said.
In addition Sacco said, “The amount of work performed by the foot during running is important over time (possibly more important in longer races), because it can facilitate effective propulsive force transmission, enabling higher ground reaction forces to be transmitted over a shorter period of time, in addition to its important capacity of loads absorption and dissipation.”
For runners then, and especially triathletes who have a history of running injuries or who would like to avoid developing them, this approach should be strongly considered. Incorporating thrice weekly twenty minute sessions to strengthening your feet could well be the key to RRI prevention in 2021.
Fists with your toes, “better than a shower and a hot cup of coffee!”
Also from Dr. Jeffrey Sankoff: How Running Gait Influences Speed and Fatigue