Noriyuki Kanzaki, Yuta Otsuka, Takayuki Izumo, Hiroshi Shibata, Hideyuki Nagao, Keita Ogawara, Hiroshi Yamada, Seiji Miyazaki, Yutaka Nakamura

Previously, we demonstrated that glucosamine-containing supplementation was effective for improving locomotor functions, especially walking speed. However, the biomechanical mechanism of efficacy has not been elucidated. This study aimed to address this challenge in subjects with knee pain, using a motion capture system. An open label study was conducted in 30 Japanese subjects with knee pain. The subjects were administered a daily supplement containing 1,200 mg of glucosamine hydrochloride, 60 mg of chondroitin sulfate, 45 mg of type II collagen peptides, 90 mg of quercetin glycosides, 10 mg of imidazole peptides, 1 mg of proteoglycan, and 5 μg of vitamin D (GCQID). The intervention continued for 16 weeks. Efficacy for locomotor functions involving the knee joint was evaluated mainly using the Japanese Knee Osteoarthritis Measure (JKOM) and the 5-question Geriatric Locomotive Function Scale (GLFS-5). To examine the biomechanical mechanism of efficacy for locomotor functions, motions of subjects in a normal walking state were captured. Gait analysis was conducted and efficacy for gait parameters such as normal walking speed, stride length, cadence, and angle of soles was evaluated. GCQID significantly improved total scores on the JKOM and GLFS-5. In gait analysis, normal walking speed, stride length, and angle of soles at the end of the stance phase were all significantly increased, but cadence did not change significantly during the intervention period. There were significant intercorrelations of changes in normal walking speed, stride length, and angle of soles at the end of the stance phase, and between changes in stride length and total JKOM score. A GCQID supplement may increase walking speed through increased stride length and angle of kicking from the ground during steps, which might be mainly associated with alleviated knee pain.