British Journal of Sports Medicine
This article by Thijs et al (2008) is basically trying to determine if there are any static or dynamic foot postures that can predispose people to knee injuries specifically the patellofemoral joint (PFJ). With most studies looking at people once they are injured when there can already be adaptations to gait this emphasis was more related with injury prevention. The study took a group of individuals, assessed their foot posture statically and dynamically using a plantar pressure plate and then got the participants to undertake a running program. Any injuries were reported and the results assessed to look for any correlations between injury and running/foot type.
There were 143 subjects enrolled for a 10-week start to run program organized by a track and field club. The exclusion criterion was no lower limb injuries in the last 6 months or any lower limb operations. 102 individuals (89 women and 13 men) completed the 10-week “start to run“ program and if any injuries were reported during the study these where examined by a Sports Medicine physician.
All subjects were evaluated using the Foot Posture Index (FPI) and plantar pressure measurements. For the plantar pressure measurements the foot was divided into eight anatomical areas. These were medial and lateral heel, metatarsals and the hallux. Subjects were asked to run over a pressure plate so data could be collected looking at vertical peak forces. Age, height, BMI and weight were also collected.
There were 17 runners (all female) who developed patella-femoral pain (PFP). The data indicated that they exerted a higher vertical peak force at the lateral heel and metatarsals 2 and 3 when landing compared to other subjects. There was no significant evidence to indicate that foot posture types affected PFP.
The Study used a reasonable sample size of 102 recreational runners. The FPI is a validated clinical tool for foot posture and using this and plantar pressure measurements before any injury has occurred were beneficial. This also helped to determine if there is any correlation between static and dynamic foot posture and injury such as pronation or supination. There was reliability of using same Sports physician to asses each injury for diagnosis.
The study was predominantly undertaken by women thus doesn’t give an accurate indicator of the effects across the genders (however no men in the study did get any PFP). The exercise plan was not described except that it was 3 times a week for 10 weeks with a goal to achieve 5km. This meant that the percentage of increases was not shown or the surface used or the base levels of individuals. Another factor relating to the subjects was their lower limb strength/stability levels as this may have been a predisposing factor on the results.
Conclusion and what does it really mean:
The study indicates that having a higher force on landing and with propulsion phase during running may predispose one to PFP. It has been reported previously that landing on the heel during running causes a higher vertical force through the limb. This increased force may cause more loading and impact shock to the patellofemoral joint that can then lead to pain. Evidence also exists that rear-foot striking will increase the force of contraction across the extensor mechanism (quadriceps) and this too may play a role in increasing the likelihood of developing PFP. It also showed that our static or resting foot posture did not affect the outcome of injury for example pronation or supinated foot types.
From my own opinion it does indicate that our static foot posture doesn’t mean we will get an injury but our running technique is more relevant. For example; if we are to run we should go to a professional for appropriate running assessment and then learn appropriate running drills to learn how to run technically better. The key here is to seek advice from appropriate medical personnel and get your technique sorted before injuries become evident.
Thanks for reading,