The purpose of this study was to analyze the validity of the newly designed functional ability test (FAT) for the normal population and patients with deficiency of the anterior cruciate ligament (ACL). The FAT consists of four tests: the figure-of-eight hop, the up-down hop, the side hop, and the single hop. Sixty control subjects and 50 patients with unilateral ACL deficiency were tested. In the control group, the values measured were significantly different between males and females in all of the tests. On the other hand, when left/right difference values were compared, no significant difference was found between males and females in any of the tests. More than 95% of control group exhibited symmetrical function in each part of the FAT, whereas in the ACL-deficient group, the percentage of patients who showed abnormal symmetry was 68% in the figure-of-eight hop, 58% in the up-down hop, 44% in the side hop, and 42% in the single hop. The percentage of ACL-deficient patients with functional asymmetry in at least one of the four tests was 82%. The FAT was found to be useful in evaluating lower limb function in ACL-deficient patients.

[Purpose] Kinematic and kinetic characteristics of the limb during side-hopping and hip/knee interaction during this motion have not been clarified. The purposes of this study were to examine the biomechanical parameters of the knee during side hop and analyze its relationship with clinical measurements of hip function. [Subjects and Methods] Eleven male college rugby players were included. A three-dimensional motion analysis system was used to assess motion characteristics of the knee during side hop. In addition, hip range of motion and muscle strength were evaluated. Subsequently, the relationship between knee motion and the clinical parameters of the hip was analyzed. [Results] In the lateral touchdown phase, the knee was positioned in an abducted and externally rotated position, and increasing abduction moment was applied to the knee. An analysis of the interaction between knee motion and hip function showed that range of motion for hip internal rotation was significantly correlated with external rotation angle and external rotation/abduction moments of the knee during the lateral touchdown phase. [Conclusion] Range of motion for hip internal rotation should be taken into consideration for identifying the biomechanical characteristics in the side hop test results.

OBJECTIVES Dynamic knee valgus is composed of hip-knee coupling. While females differ from males in passive hip motion, hip rotation range may alter muscle mechanics and neuromuscular activity. This study aimed to compare knee abduction biomechanics during double-legged drop-landing between males and females with different hip rotation ranges.METHODS This study included five females with the range of hip internal rotation (IR) > the range of hip external rotation (ER), five females with ER>IR, four males with IR>ER, and five males with ER>IR. There was no difference in other hip motions among them or no difference in hip muscle strength between the same sex groups. Three-dimensional motion analyses of the hip and knee joints were performed during double-legged drop-landing.RESULTS Multiple regression analysis of females with IR>ER showed that peak knee abduction moment (KAM) was associated with maximal hip abduction moment before detecting peak KAM whereas peak knee abduction angle (KAA) correlated with no variable. In females with ER>IR, peak KAM was associated with maximal hip ER moment before detecting peak KAM, hip ER muscle strength and hip adduction range while peak KAA correlated with peak hip abduction moment before detecting peak KAM. In males with IR>ER, peak KAM was associated with hip ER range and hip adductor strength whereas peak KAA correlated with maximal hip ER moment and maximal hip IR angle during landing. In males with ER>IR, peak KAM was associated with hip extensor strength, hip abduction range and hip flexion range whereas peak KAA correlated with hip ER moment before detecting peak KAM, hip ER muscle strength, and hip adduction range.CONCLUSIONS Hip rotation range may differentially affect hip-knee coupling strategy for knee abduction control during double-legged drop-landing between males and females.

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