November 2014

Resistance is useful: Ankle band activates hip during landing

In the moment: Sports medicine

Photo illustrates positioning of the resistance band just above the ankles. (Photo courtesy of Boyi Dai, PhD.)

Photo illustrates positioning of the resistance band just above the ankles. (Photo courtesy of Boyi Dai, PhD.)

By Jordana Bieze Foster

Wearing a resistance band around the ankles during jump landings is associated with increased hip abduction moments and gluteus medius activation, and may be a more functional alternative to the therapeutic exercises typically used to train the same muscles, according to research from the University of Wyoming in Laramie.

Interventions to increase hip abductor activation are often utilized in anterior cruciate ligament (ACL) injury prevention programs, specifically to help control knee abduction and medial displacement during landing. The resistance-band intervention may allow athletes to transfer gluteus medius strength and activation gains to sport-specific movements more effectively than some other exercises, theoretically resulting in more effective injury prevention.

But, in a 2012 study, researchers from the University of Waterloo in Canada found that wearing a resistance band around the distal thighs during body-weight squat and jumping exercises was actually associated with an increased knee abduction moment, which is a risk factor for ACL injury.

The intervention used in the Wyoming study was designed with those previous findings in mind, said Boyi Dai, PhD, an assistant professor of kinesiology and health at the University of Wyoming and first author of the study.

“We placed the band at the ankles instead of the thighs because this placed the band further away from the hip joint and created a greater moment arm from the hip joint to the medial force applied by the band,” Dai said. “If we place the band at the thighs, the effects on muscle activation and hip moments are likely to be less. But we were not sure whether the external knee abduction moments would change if we changed the placement.”

Dai and colleagues assessed 28 college-aged recreational athletes (15 women) as they did jump-landing-jump tasks with and without a resistance band applied to the lower shanks, with the cuffs of the band directly above the ankle joints. When jumping with the resistance band, the athletes were instructed to maintain the same form as when jumping without the band.

Average hip abduction moments during prelanding and early landing were significantly higher with the resistance band than without, as was gluteus medius electromyography at the same two time points. The findings were epublished October 3 by the Journal of Biomechanics.

Knee abduction moment did not differ significantly between the two conditions. However, like the Waterloo researchers, the Wyoming group also found that resistance-band use was associated with some small but significant kinematic changes that could potentially increase ACL injury risk, including decreased maximum knee flexion angle and decreased initial hip abduction angle.

This suggests that if resistance-band based landing exercises are to be used clinically, additional instructions or feedback may be necessary to ensure proper landing technique—particularly in athletes who are already at high risk for an ACL injury.

“I think training with a band will be especially beneficial for those with weak hip abductors. However, we do not want the band to induce negative consequences to their landing mechanics. That’s why additional feedback may be needed,” Dai said. “For example, video and verbal feedback is commonly used to increase knee flexion angle during landing, and greater knee flexion is associated with decreased ACL loading. So, in the future, we can consider combining a resistance band with video feedback to increase muscle activation and hip moments as well as improve lower extremity biomechanics such as knee flexion.”

The study did not assess hip strength in the participants, but the researchers believe that individuals with gluteus medius weakness may have the most to gain from a resistance-band intervention. However, clinical use of the resistance band technique would likely involve different levels of resistance depending on an individual athlete’s needs, Dai said

“We only used one band with one placement. We expect that a band with greater stiffness will increase the challenges for the hip abductors,” he said. “It is also reasonable to train individuals progressively with different bands and placements.”

Sources:

Dai B, Heinbaugh EM, Ning X, Zhu Q. A resistance band increased internal hip abduction moments and gluteus medius activation during pre-landing and early-landing. J Biomech 2014 Oct 3. [Epub ahead of print]

Gooyers CE, Beach TA, Frost DM, Callaghan JP. The influence of resistance bands on frontal plane knee mechanics during body-weight squat and vertical jump movements. Sports Biomech 2012;11(3):391-401.

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