Hip-Abductor Fatigue and Single-Leg Landing Mechanics in Women Athletes

Abstract

Context: Reduced hip-abductor strength and muscle activation may be associated with altered lower extremity mechanics, which are thought to increase the risk for anterior cruciate ligament injury. However, experimental evidence supporting this relationship is limited. Objective: To examine the changes in single-leg landing mechanics and gluteus medius recruitment that occur after a hip-abductor fatigue protocol. Design: Descriptive laboratory study. Patients or Other Participants: Twenty physically active women (age = 21.0 ± 1.3 years). Intervention(s): Participants were tested before (prefatigue) and after (postfatigue) a hip-abductor fatigue protocol consisting of repetitive side-lying hip abduction. Main Outcome Measure(s): Outcome measures included sagittal-plane and frontal-plane hip and knee kinematics at initial contact and at 60 milliseconds after initial contact during 5 single-leg landings from a height of 40 cm. Peak hip and knee sagittal-plane and frontal-plane joint moments during this time interval were also analyzed. Measures of gluteus medius activation, including latency, peak amplitude, and integrated signal, were recorded. Results: A small (<1°) increase in hip-abduction angle at initial contact and a small (<1°) decrease in knee-abduction (valgus) angle at 60 milliseconds after contact were observed in the postfatigue landing condition. No other kinematic changes were noted for the knee or hip at initial contact or at 60 milliseconds after initial contact. Peak external knee-adduction moment decreased 27% and peak hip adduction moment decreased 24% during the postfatigue landing condition. Gluteus medius activation was delayed after the protocol, but no difference in peak or integrated signal was seen during the landing trials. Conclusions: Changes observed during single-leg landings after hip-abductor fatigue were not generally considered unfavorable to the integrity of the anterior cruciate ligament. Further work may be justified to study the role of hip-abductor activation in protecting the knee during landing.

Effects of Two Fatigue Protocols on Impact Forces and Lower Extremity Kinematics during Drop Landings: Implications for Noncontact Anterior Cruciate Ligament Injury

“…Kernozek et al also found that male subjects effectively reduced the magnitude of the anterior knee shear force by the means of a greater peak knee flexion angles postfatigue during a DL task, which partially supports our findings [32]. Apart from the above two results, the participants had approximately the same hip and knee flexion angle at initial contact during a single-leg DL task following a hip abductor fatigue protocol in Patrek et al's study [33], which indicated that the role of hip abductor activation in protecting the knee during landing needed to be further justified. In addition, fatigue level was divided into five grades, namely, prefatigue, 25% fatigue, 50% fatigue, 75% fatigue, and 100% fatigue, in Mclean and Samorezov's study [22].…”

A resistance band increased internal hip abduction moments and gluteus medius activation during pre-landing and early-landing

“…Activation of the hip abductors can generate an internal hip abduction moment to decrease the medial displacement of the knee and knee abduction angle. Investigators have studied the relationships between the hip abductor strength, hip abductor activation, and knee abduction angle during landing and squatting tasks (Homan et al, 2013;Jacobs and Mattacola, 2005;Jacobs et al, 2007;Patrek et al, 2011;Russell et al, 2006;Wallace et al, 2008;Zeller et al, 2003), but limited intervention strategies are available to train the hip abductors during jump-landing. Several investigators have described hip abductor activation during functional tasks (Boudreau et al, 2009;Distefano et al, 2009;Dwyer et al, 2010), however, muscles demonstrate specificity between training and testing tasks for strength gains (Hortobagyi et al, 1996;Rutherford and Jones, 1986;Wilson et al, 1996).…”

A Review of Recent Perspectives on Biomechanical Risk Factors Associated with Anterior Cruciate Ligament Injury

“…Weakness and/or insufficient activation of these muscles in females may also contribute to the greater incidence of non-contact ACL injury in females. Some studies have found an association between reduced hip abduction and external rotation strength and increased knee valgus motion during landing (Jacobs, Uhl, Mattacola, Shapiro, & Rayens, 2007;Wallace et al, 2008), however other studies have contradicted these findings (Bolgla, Malone, Umberger, & Uhl, 2008;Lawrence, Kernozek, Miller, Torry, & Reuteman, 2008;Patrek, Kernozek, Willson, Wright, & Doberstein, 2011). The reason for the discrepancy between these studies may, in part, be due to a lack of association between the muscle force produced during a dynamic task and strength during isometric or isokinetic tests, since other factors will also influence muscle force during a dynamic task.…”