Inter-joint coordination and gait variability in knee osteoarthritis (KOA) has not been well investigated. Hip-knee cyclograms can visualize the relationship between the hip and knee joint simultaneously. The aim of this study was to elucidate differences in inter-joint coordination and gait variability with respect to KOA severity using hip-knee cyclograms. Fifty participants with KOA (early KOA, n = 20; advanced KOA, n = 30) and 26 participants (≥ 50 years) without KOA were recruited. We analyzed inter-joint coordination by hip-knee cyclogram parameters including range of motion (RoM), center of mass (CoM), perimeter, and area. Gait variability was assessed by the coefficient of variance (CV) of hip-knee cyclogram parameters. Knee RoM was significantly reduced and total perimeter tended to be decreased with KOA progression. KOA patients (both early and advanced) had reduced stance phase perimeter, swing phase area, and total area than controls. Reduced knee CoM and swing phase perimeter were observed only in advanced KOA. Both KOA groups had a greater CV for CoM, knee RoM, perimeter (stance phase, swing phase and total) and swing phase area than the controls. Increased CV of hip RoM was only observed in advanced KOA. These results demonstrate that hip-knee cyclograms can provide insights into KOA patient gait.

AimThis study aimed to evaluate the prevalence and associated factors of radiographic hip osteoarthritis (OA) in the Korean community‐dwelling population.MethodsThis study included 11 814 individuals (5025 men and 6789 women) ≥50 years of age from the Korea National Health and Nutrition Examination Surveys. Radiographic hip OA was defined as having a Kellgren–Lawrence grading scale score ≥2. Painful hip OA was defined as radiographic hip OA with the presence of hip pain. The prevalence of radiographic hip OA was evaluated with respect to age group, sex and presence of hip pain. The associations of sociodemographic and clinical variables with hip OA and hip pain were assessed using multivariable logistic regression analyses.ResultsThe weighted prevalence of radiographic hip OA and painful hip OA was 1.1% and 0.2%, respectively, in Korea. Older age (≥75 years) and male sex were independently associated with radiographic hip OA and painless hip OA. Comorbid musculoskeletal pain (knee pain) was independently associated with painful hip OA. The difference between painful and painless hip OA was the presence of comorbid musculoskeletal pain (knee pain and low back pain). Although hip pain was more common in women than in men, it was associated with the severity of hip OA only in men.ConclusionsRadiographic hip OA is rare in Korean middle‐aged and elderly people. Furthermore, hip pain is infrequent in radiographic hip OA. Geriatr Gerontol Int 2021; 21: 20–26.

Park, JH, Seo, KS, and Lee, S-U. Effect of superimposed electromyostimulation on back extensor strengthening: a pilot study. J Strength Cond Res 30(9): 2470-2475, 2016-Electromyostimulation (EMS) superimposed on voluntary contraction (VC) can increase muscle strength. However, no study has examined the effect of superimposing EMS on back extensor strengthening. The purpose of this study was to determine the effect of superimposed EMS on back extensor strengthening in healthy adults. Twenty healthy men, 20-29 years of age, without low-back pain were recruited. In the EMS group, electrodes were attached to bilateral L2 and L4 paraspinal muscles. Stimulation intensity was set for maximally tolerable intensity. With VC, EMS was superimposed for 10 seconds followed by a 20-second rest period. The same protocol was used in the sham stimulation (SS) group, except that the stimulation intensity was set at the lowest intensity (5 mA). All subjects performed back extension exercise using a Swiss ball, with 10 repetitions per set, 2 sets each day, 5 times a week for 2 weeks. The primary outcome measure was the change in isokinetic strength of the back extensor using an isokinetic dynamometer. Additionally, endurance was measured using the Sorensen test. After 2 weeks of back extension exercise, the peak torque and endurance increased significantly in both groups (p ≤ 0.05). Effect size between the EMS group and the SS group was medium in strength and endurance. However, there was no statistically significant difference between 2 groups. In conclusion, 2 weeks of back extensor strengthening exercise was effective for strength and endurance. Superimposing EMS on back extensor strengthening exercise could provide an additional effect on increasing strength.