Variability of movement in hips, knees linked to ankle stability

Individuals who experience more movement at the hips and knees may be less likely to suffer from chronic instability of the ankle, according to a recent study published in Clinical Biomechanics journal examining how people move their hip and knee joints before and after ankle sprains.

“Increased movement variability at the hips and knees may be beneficial in avoiding chronic ankle instability,” Cathleen Brown Crowell, PhD, ATC, assistant director at the department of kinesiology at the University of Georgia, told Orthopedics Today. “Landing a little bit different every time may mean you have flexibility to try different landing strategies that could help you avoid re-injury.”

Brown Crowell and her team separated 88 participants (39 males, 49 females) into three groups: an uninjured control, active people with ankle sprain complications and people who had been previously injured but experienced no pain. The control was further divided into two groups based on incidences of participants’ ankles giving way and joint laxity, according to the abstract.

Researchers looked for reasons why some people were able to actively return to sports while others were hindered by pain. Participants dressed in a body suit that tracked the movements of their ankle, knee and hip joints, according to a press release. The team then asked participants to jump toward a metal target located 27.5 inches away and land on one foot without assistance. Results averaged over 10 different trials were measured in anterior, lateral and medial directions.

The control group bent their knees and swayed their hips side-to-side more often that the other groups, while the injured groups were unable to use their joints as effectively, researchers said. The study noted the group with injured ankles had difficulty using their proximal hip and knee joints; the pain-free group had similar difficulties using their joints, despite “coping” with their injuries.

Brown Crowell noted the study is only a “snapshot in time” and that it is unknown whether the injured groups use their joints this way because they are injured or if they injured themselves because of the way they land. Further study is needed to determine which movements are helpful by examining joints in combination. Researchers could then use the movement patterns to develop additional rehabilitation techniques.

Reference:

Brown C, Bowser B, Simpson J. Movement variability during single leg jump landings in individuals with and without chronic ankle instability. Clin Biomech. 2011; Published online before print. doi:10.1016/j.clinbiomech.2011.07.012

Disclosure: Brown has no relevant financial disclosures.

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