By P.K. Daniel
Deficits in single-leg balance may contribute to the high rate of injuries among endurance athletes, but hip strength may not, according to two studies presented in February at the American Physical Therapy Association’s annual Combined Sections Meeting in Anaheim, CA.
Both studies were conducted by researchers at Ironman Sports Medicine Institute, Memorial Hermann Health System, and Texas Woman’s University, all in Houston, TX.
In the first, researchers found the anterior reach component of the Y Balance Test (YBT) differed significantly between endurance athletes with a history of lower extremity injury in the previous three years and healthy participants.
The 71 male and 78 female athletes, who were not seeking medical attention, were selected from local running clubs and participants in the Houston Marathon and Ironman races. Of the 149 athletes, 61 reported a recent history—within 36 months—of lower extremity injury.
While medial, lateral, and composite reach scores were not statistically different between limbs for either group, the researchers found a recent history of lower extremity injury was negatively associated with anterior reach. The injured athletes also demonstrated significantly less mean anterior reach for the involved lower extremity (57 ± 14.5 cm) compared with the uninvolved extremity (63.4 ± 13.1 cm) and the uninjured athletes (64.1 ± 14.6 cm).
“I would say the most interesting aspect of the study was the dramatic difference in anterior reach distance on the involved side within the previous injury group,” said lead author Andrew J. Nasr, PT, DPT, CSCS, now a staff physical therapist with the University of Texas Southwestern Medical Center in Dallas, TX, who presented the findings. “We hypothesized there would be a difference, but did not expect such a difference.”
The researchers believe their study is the first to investigate functional performance in a sample of endurance athletes using testing procedures common to field sports. The findings suggest that utilization of the Y Balance anterior reach test to detect balance deficits may be able to help identify athletes at risk for lower extremity injury or to help determine whether an athlete is ready to return to sports.
“While we cannot make sweeping conclusions with the findings due to the retrospective nature of the study and inherent limitations, we do feel that the Y Balance can be used as a good clinical tool to track this athletic population as we rehab them back to sport participation,” Nasr said.
Because little is known regarding endurance athletes’ risk factors for injury, the same researchers conducted a second study involving the same participants to determine the relationship between hip abduction strength and history of lower extremity injury. For this study, the researchers also analyzed skill level (elite vs recreational) as a possible contributing factor.
The 149 athletes participated in a single session of clinical and functional testing. Surprisingly, there was no correlation between hip abduction strength and history of a lower extremity injury in the previous three years.
That lack of correlation was true for both skill-level groups. Among the injured recreational athletes (<25 mi/wk), no differences in hip abduction strength were observed between the injured (50.6 ± 18.2 lb) and uninjured limbs (51.9 ± 18.2 lb). Similarly, no differences were noted for hip abduction strength between injured (54.9 ± 18.8 lb) and uninjured sides (55 ± 11.7 lb) for elite injured athletes.
“Our data didn’t support our hypothesis that there would be a difference in hip abduction strength and previous [lower extremity] injury,” said lead author Caitlyn Lang, PT, DPT, a staff physical therapist at Memorial Hermann Health System, who presented the findings.
However, the researchers did find a positive relationship between hip abduction strength and a top-three placement within a competitive event, suggesting that hip abduction strength has a stronger association with performance than with injury risk.
Nasr AJ, Lang C, Duncan BR, et al. Deficits in single-leg balance are associated with recent lower extremity injuries among asymptomatic endurance athletes currently participating in sport. J Orthop Sports Phys Ther 2016;46(1):A46.
Lang C, Nasr AJ, Duncan BR, et al. The relationships between hip abduction strength lower extremity injury history & performance in endurance athletes. J Orthop Sports Phys Ther 2016;46(1):A43.