Kyoto University · Medicine
Professor Momoko Yamagata's research lab specializes in neuromuscular control, postural stability, and lower-limb biomechanics, with a focus on understanding how muscle coordination and activation patterns influence joint loading and fall risk. The lab investigates the role of muscle coactivation in postural control using advanced analytical methods such as rambling-trembling decomposition and uncontrolled manifold (UCM) analysis. A key research direction involves examining sex differences and pathological changes—particularly in knee osteoarthritis (KOA)—in ambulatory mechanics and knee contact forces. The lab also employs musculoskeletal modeling to evaluate the functional impact of individual muscle contributions to joint stability and load distribution.
Figures are computed from collected data and may differ slightly.
We explored the effects of voluntary coactivation of agonist-antagonist leg and trunk muscles on stability of vertical posture. Young healthy subjects performed several tasks while standing with no additional muscle coactivation, low coactivation, and high coactivation. Postural stability was estimated using indices of postural sway and of intertrial variance in the space of muscle groups with parallel scaling of activation levels (M-modes). An increase in coactivation led to a significant incre
Our study compared the results of two methods of analysis of postural sway during human quiet standing, the rambling-trembling (<i>Rm</i>-<i>Tr</i>) decomposition and the analysis of the point of intersection of the ground reaction forces (<i>zIP</i> analysis). Young, healthy subjects were required to stand naturally and with an increased level of leg/trunk muscle co-activation under visual feedback on the magnitude of a combined index of muscle activation (muscle mode). The main findings includ
We verified that the high variance in segmental configurations that destabilize the CoM in the vertical direction was related to future falls. The variables of UCM analysis can be useful for evaluating fall risk.
The main objective of this study was to determine which muscle force reduction, among the vastus muscles (VAS), rectus femoris (RF), gluteus medius (Gmed), and gluteus maximus (Gmax) most significantly influenced the knee contact force. Ten young adults walked at a comfortable speed. The medial and lateral knee contact forces (KCF<sub>med</sub> and KCF<sub>lat</sub>) were computed by a musculoskeletal model with full-force-generating capacity and four muscle inactivation models that separately c
The current study is the first to consider sex as a biological variable into ambulatory mechanics in the development of KOA. We discovered that sex-dependent alterations in knee biomechanics is a function of the presence of KOA, indicating that KOA disease may be a driver of the sex-dependent biomechanical alterations or vice versa. Although no strong conclusion can be drawn because of the low quality of evidence, these findings provide new insight into the sex differences in ambulatory knee bio
Open papers in the app to read, cite, and organize with AI.
