Passive stiffness of the quadriceps predicts the incidence of clinical knee osteoarthritis in twelve months. European journal of physical and rehabilitation medicine BACKGROUND:Quadriceps weakness is a known risk factor for the onset of knee osteoarthritis (OA). In addition to muscle weakness, increased passive stiffness of the quadriceps may affect knee biomechanics and hence contribute to the pathogenesis of knee OA. However, the association between quadriceps stiffness and the risk of knee OA development has not been prospectively investigated. AIM:The aim of this study was to investigate how baseline quadriceps passive stiffness predicts the incidence of clinical knee OA at the 12-month follow-up. DESIGN:Prospective cohort study. SETTING:University laboratory. POPULATION:Community-dwelling adults aged 60-80 years were recruited. We excluded participants with: 1) knee pain or known arthritis; 2) knee injury; 3) knee or hip joint replacement, 4) cognitive impairment; or 5) neurological conditions. METHODS:At baseline, passive stiffness of the three superficial quadriceps muscle heads (rectus femoris [RF], vastus lateralis [VL], and vastus medialis oblique [VMO]) was evaluated using shear-wave ultrasound elastography. Knee muscle (quadriceps and hamstrings) strength was tested using a Cybex dynamometer. Knee OA was defined based on clinical criteria 12 months after baseline measurements. Generalized estimating equations were used to examine the associations of quadriceps stiffness and knee muscle strength with the risk of knee OA, controlling for age, sex, Body Mass Index, comorbidities, and activity level. RESULTS:The analyses included 158 knees (58.2% females, age: 65.6±4.1 years). Twenty-eight knees (17.7%) were classified as having clinical OA at 12 months. Compared with the lowest stiffness tertiles, the highest stiffness tertiles of the RF (relative risk =5.31, 95% CI: 1.34-21.0), VMO (4.15, 1.04-16.6), and total superficial quadriceps (6.35, 1.48-27.3) at baseline were significantly associated with a higher risk of knee OA at the follow-up. The highest strength tertile of quadriceps has a trend of association with a lower risk of knee OA than the lowest tertile (0.18, 0.03-1.25, P=0.083). CONCLUSIONS:Greater passive stiffness of the quadriceps at baseline was associated with a higher risk of clinical knee OA incidence at the 12-month follow-up. CLINICAL REHABILITATION IMPACT:Interventions for reducing the passive stiffness of the quadriceps should be included in preventative training programs for older adults. 10.23736/S1973-9087.22.07634-1

Muscle Thickness and Echo Intensity of the Abdominal and Lower Extremity Muscles in Stroke Survivors. Monjo Hiroki,Fukumoto Yoshihiro,Asai Tsuyoshi,Shuntoh Hisato Journal of clinical neurology (Seoul, Korea) BACKGROUND AND PURPOSE:This study compared the muscle thickness (MT) and echo intensity (EI) of the abdominal, thigh, and lower leg muscles between the paretic and nonparetic sides in chronic stroke survivors. METHODS:Thirty-two stroke survivors living in the community participated in this study. The MT and EI, which are indicators of muscle mass and intramuscular fat or connective tissue, were assessed in the rectus abdominis, external oblique, internal oblique, transversus abdominis, rectus femoris, vastus intermedius, vastus lateralis, vastus medialis, tibialis anterior, gastrocnemius, and soleus via transverse ultrasound imaging. In addition, a possible indicator of physical activity-the frequency of going out per week-was evaluated. RESULTS:All quadriceps muscles and the tibialis anterior were significantly thinner and the EI values of the vastus intermedius, vastus lateralis, vastus medialis, and soleus were significantly higher in the paretic limb than the nonparetic limb. The MT and EI values of abdominal muscles did not differ significantly between the two sides. The MT values of the paretic rectus femoris, vastus lateralis, and vastus medialis were significantly associated with the frequency of going out after adjusting confounding factors. The MT of the nonparetic vastus lateralis was significantly associated with latency from stroke onset after adjusting confounding factors. CONCLUSIONS:Our results indicate that quantitative and qualitative changes on the paretic side in stroke survivors were the most robust in the thigh muscles, whereas such changes might not occur in the abdominal muscles. 10.3988/jcn.2018.14.4.549