[Purpose] Knee osteoarthritis can alter gait variability; however, few studies have investigated the associating factors with gait cycle time variability. The first objective was to compare gait cycle variability between female patients with knee osteoarthritis and healthy elderly females and to determine gait characteristics in patients with knee osteoarthritis. The second objective was to identify the associating factors with gait cycle time variability. [Participants and Methods] The participants included 24 female patients diagnosed with knee osteoarthritis and 12 healthy elderly females. Gait cycle variability (coefficient of variation of gait cycle time), knee extension range of motion, knee extension strength, 5-m walk test, Timed Up & Go Test, and Western Ontario and McMaster Universities Osteoarthritis Index were measured. All assessment results were compared between the knee osteoarthritis and healthy groups. [Results] Gait cycle time variability was significantly higher in the knee osteoarthritis group than in the healthy group. Further, it showed a significant positive correlation with the 5-m walk test and the Western Ontario and McMaster Universities Osteoarthritis Index. [Conclusion] Patients with knee osteoarthritis presented greater gait cycle variability than that of healthy individuals. Therefore, rehabilitation to improve gait variability might enhance the quality of life of patients with knee osteoarthritis.

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Knee osteoarthritis can alter gait variability. However, few studies have compared the temporal factors of the gait cycle between patients with knee osteoarthritis and healthy subjects. Furthermore, no studies have investigated the relationship between gait variability and potential contributing factors (knee joint functions such as muscle strength) in knee osteoarthritis. The first objective of this study was to compare gait cycle variability between female patients with knee osteoarthritis and healthy elderly women to determine gait characteristics in patients with knee osteoarthritis. The second objective was to examine whether gait cycle variability in knee osteoarthritis is associated with potential contributing factors. Twenty-four female patients diagnosed with knee osteoarthritis and 12 healthy elderly women participated. Gait cycle variability (coefficient of variation of gait cycle time), knee extension range of motion, knee extension strength, 5-meter walk test, Timed Up & Go Test, and Western Ontario and McMaster Universities Osteoarthritis Index were measured. All assessment results were compared between the knee osteoarthritis and healthy groups. Gait cycle variability was significantly higher in the knee osteoarthritis group (3.2%) compared to the healthy group (2.1%). A significant positive correlation was found between the gait cycle variability and 5-meter walk test (r=0.46) and Western Ontario and McMaster Universities Osteoarthritis Index (r=0.43). The gait of patients with knee osteoarthritis may be more unstable than that of healthy individuals. In addition, unstable gait may be associated with gait speed and quality of life. Therefore, we believe that rehabilitation to improve unstable gait can enhance the quality of life of patients with knee osteoarthritis.

The purpose of this study was to investigate whether joint function and physical ability differ according to the presence of pain during knee joint extension in knee osteoarthritis (knee OA). [Participants and Methods] Thirty-one female patients with knee OA were included. The presence of pain during knee extension was assessed under three conditions: (1) active knee extension, (2) stepping, and (3) one-legged squatting. In addition, knee extension range of motion (ROM), knee extension strength, 5-meter walking distance (5MWT), Timed Up & Go Test (TUG) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were evaluated. [Results] The WOMAC score was significantly higher, knee extension strength and ROM were significantly lower, and 5MWT (maximum speed) and TUG were significantly slower in the group with pain during active knee extension. Moreover, the group with pain during stepping had a significantly slower 5MWT (comfortable speed). [Conclusion] In patients with knee OA, pain during knee extension was associated with poorer knee joint function and lower gait speed.

[Purpose] In response to loading of the femur, the lower leg outwardly rotates, thereby inducing "kneein". Through this lower leg outward rotation, knee-in, induces valgus of the knee joint. The objective of this study was to clarify the relationships of the muscle activities of the hamstring, which is a rotator muscle, and the vastus medialis and vastus lateralis muscles which contribute to the lateral stability of the knee, at the time of one-leg jump landing.[Subjects] The subjects were 27 healthy female university students with no medical history of knee disease or injury.[Method] The activities of the vastus medialis (VM), vastus lateralis (VL), semimembranosus (SM) and biceps femoris (BF) were derived from electromyography (EMG) and the maximum valgus knee angle was calculated.[Results] A significant positive correlation (p<0.05, r=0.40) was found between the ratio, BF:SM (the ratio of the activities of the medial and lateral hamstring muscles) and the maximum valgus knee angle.[Conclusion] The results suggest that at the time of one-leg jump landing, the valgus knee angle will be large for persons with a high BF:SM ratio. Key words: jump landing, valgus knee angle, muscle activation of the knee