A recent study by investigators from Hospital for Special Surgery shows that athletes making a cut on natural grass while wearing cleats may put less strain on their ACL.
Using cadaveric models, the investigators examined the strain placed on the ACL during the following shoe-surface interactions:
- Astroturf and turf shoe;
- modern playing turf and turf shoe;
- modern turf and cleat; and
- natural grass and cleat.
It appears that a similar cut made on four different surfaces, the best strain profile is in grass/cleat combinations, Mark Drakos, MD, an investigator of the study and former orthopedic fellow at Hospital for Special Surgery (HSS), stated in an HSS press release. So, there is less force occurring at your ligament for the same cut on that particular surface using this model.
Drakos noted that the investigators studied noncontact injuries. While other researchers have examined the interaction between shoe-surface combinations and loading at the foot, the HSS study is one of the first to investigate how shoe-surface interactions impact the knee.
These are injuries where an athlete plants his or her foot while making a cut and blows out his or her knee, Drakos stated in the release. The reason that I think this is so interesting is because there are still environmental factors, which have yet to be optimized. We don't know all the science behind why ACL injuries may be more common on turf than on grass. This study starts developing some of the science behind that, so that it can be looked at more closely because, at the end of the day, I think we need to optimize some of those environmental factors.
For the study, Drakos and his colleagues used the knee, foot and ankle of eight cadavers and rigged the specimens in a standing position with the knees flexed at 30°. They constructed a device that placed weight on the leg to simulate weight-bearing. They also placed a turf box under the foot with the desired testing surface and put a force plate beneath the turf box. In addition, they placed a lazy Susan under the force plate to rotate the plate and turf box.
The investigators discovered that the natural grass and cleat combination placed a statistically lower maximum strain on the ACL compared to the other constructs. The Astroturf and turf shoe, modern playing turf and turf shoe; and modern turf and cleat combinations had 80.2%, 47.5% and 45.1% greater strain respectively, than the natural grass and cleat combination.