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Wheels of Motion: Oscillatory Potentials in the Motor Cortex
Published in Alexa Riehle, Eilon Vaadia, Motor Cortex in Voluntary Movements, 2004
FIGURE 7.6 Preparatory l0-Hz rhythm synchronized to movement onset. Both human EEG recordings from C3. (A) Subject performed continuous rhythmic tapping at a self-paced rate of l.27 Hz. (The subject was a 20-year-old highly trained pianist.) Mean EEG for 50 taps, aligned on moment of tap contact. (B) Subject performed continuous rhythmic finger flexion at a self-paced rate of l.56 Hz; mean EEG and EMG for 40 movements, aligned on EMG onset (flexor digitorum superficialis muscle). (Unpublished data of W. MacKay and S. Makhamra.55)
Functional Anatomy and Biomechanics
Published in Emeric Arus, Biomechanics of Human Motion, 2017
Musculus flexor digitorum brevis is equivalent to the flexor digitorum superficialis muscle of the arm. This muscle has four fasciculi with their tendons and is fixed to the middle phalanges of the second to the fifth toes. Insertion: The origin is on the calcaneal tuberosity and plantar aponeurosis. It distally inserts on the middle phalanges of the second to the fifth toes. Action: It is the flexor of the second to the fifth toes. Innervation is assured by the medial plantar nerve (L4 and L5).
Grasping VR: Presence of Pseudo-Haptic Interface Based Portable Hand Grip System in Immersive Virtual Reality
Published in International Journal of Human–Computer Interaction, 2020
Mingyu Kim, Jinmo Kim, Kisung Jeong, Changhun Kim
Next, a system to measure hand gestures and movements is implemented, and the forces generated in hand grips are designed to accurately reflect the measurements in VR. This study designs a hardware structure by mounting EMG sensors and a communication model on an Arduino board to accurately measure force and produce a simple structure. EMG sensors, which are frequently used in biomechanics for human and animal behaviors, measure and record electrical signals in the cells of skeletal muscles. The two electrodes (measurement and reference electrodes) of each sensor are attached around the muscles through bio electrodes for human body contact. The potential difference between two electrodes is amplified by an automatic amplifier (INA), and EMG signals are output with noise removed through a notch filter and low-pass filter (LPF). In this study, force is measured in real time through EMG sensors attached to the flexor digitorum superficialis muscle of the arm, which can quickly measure the hand grip force with an error lower than that for other surrounding muscles.
Middle finger and ball movements around ball release during baseball fastball pitching
Published in Sports Biomechanics, 2018
Tomoyuki Matsuo, Tsutomu Jinji, Daisaku Hirayama, Daiki Nasu, Hiroki Ozaki, Daisuke Kumagawa
One feasible explanation concerning this phenomenon is the oscillation due to high stiffness resulting from co-contraction around ball release. According to the electromyographic results reported by DiGiovine, Jobe, Pink, and Perry (1992), digital flexor muscles (the flexor digitorum superficialis muscle, flexor carpi radialis, and flexor carpi ulnaris) were highly active during the acceleration phase, ranging from 80 to 120% of the maximal manual muscle test. Digital extensor muscles (the extensor digitorum communis, extensor carpi radialis longus, and extensor carpi radialis brevis) showed low or moderate activity in the acceleration phase, ranging from 30 to 55% of the maximal manual muscle test. These electromyographic results were, unfortunately, the summation of the electromyogram findings during the acceleration phase, but not for the short period around ball release. Thus, the muscle activity around ball release may or may not be different from their results. However, it seems that some co-contraction should occur during baseball pitching. Delicate adjustments of stiffness based on the balance between flexion torque and extension torque may be key factors in this phenomenon. It is therefore suggested that finger muscle training with co-contraction and force adjustment training may be useful for improving pitching performance.