Bagnoli 8 emg system

Surface EMG signals (Bagnoli 8 EMG System, DELSYS, USA) were obtained from the RF, VL, and VM with using pre‐amplified bipolar surface electrodes (DE‐2.1, 1 × 10 mm², 10 mm inter‐electrode distance). Muscle belly and fascicle longitudinal directions were confirmed by ultrasonography (ACUSON S2000, Siemens Medical Solutions, USA). The electrodes were placed after the skin areas under the electrodes were shaved, rubbed with sandpaper, and cleaned with alcohol. The reference electrode was placed on the left medial malleolus. To match the electrode regions throughout the testing, the participants were asked to keep the marks on their skin. Torque and EMG signals were obtained at 2 kHz using an A/D converter (PowerLab16/35, ADInstruments, Australia) and stored to a computer. Analyses were conducted with LabChart software (version 8, ADInstruments, Australia), and the root mean square values of EMG signals (EMG‐RMS) of the three muscles during knee extensor MVC and RF during hip flexor MVC were determined over a 0.5‐seconds period around the maximal torque.

Electromyography (EMG) were recorded using bipolar surface electrodes (DE-2.1 EMG Sensor, Delsys, Natick, MA) from upper-limb muscles involved with flexion or extension at the elbow or shoulder (6 (link), 23 (link)): the posterior deltoid (DP), the lateral head of the triceps (TLAT), the brachioradialis (BR), and pectoralis major (PM). Before the electrode placement on the muscle belly, the skin was cleaned and lightly abraded with cotton gauze and rubbing alcohol. The electrode contacts were covered with conductive gel. A ground electrode was placed on the lateral side of the elbow. EMG signals were amplified (Bagnoli-8 EMG System, Delsys, Natick, MA) and digitized at 1 KHz.

In order to evaluate neuromuscular activity of the knee extensors, a surface EMG system (Bagnoli 8 EMG System; Delsys Inc., Boston, MA, United States) with pre-amplified bipolar active surface EMG electrodes (electrode shape, parallel bar; electrode size, 1 × 10 mm; interelectrode distance, 10 mm; DE-2.1, Delsys Inc.) was used. After shaving, abrasion, and cleaning with alcohol, the electrodes were placed over the rectus femoris (RF), vastus lateralis (VL), and vastus medialis (VM). The longitudinal locations of the electrodes were at proximal 50% of the thigh length (distance between the greater trochanter and the lateral aspect of the knee joint space) for RF, 30% for VL, and 80% for VM. The transverse location of each electrode was at the center of muscle width. Using an ultrasonographic device (ACUSON S2000; Siemens Medical Solutions, Ann Arbor, MI, United States), direction of the electrode was aligned with the fascicle direction of each muscle. The reference electrode was attached on the left medial malleolus. The EMG signal was acquired at 2 kHz, and was filtered with 20–450 Hz bandpass filters.

Four EMG channels were recorded, from Mentalis, left Risorius, right Risorius, and left Temporalis muscles. The skin was first cleaned using alcohol wipes, and EMG sensors (Delsys 2.1 single differential configuration, Delsys Inc., Boston, USA) were placed over the muscles using double-sided adhesive tape. The reference electrode was placed on right clavicle. The raw EMG signals were filtered (20–450 Hz band pass filter) and amplified 10,000 times by a Delsys Bagnoli-8 EMG System (Delsys Inc., Boston, USA). The EMG signals were digitized at a sampling rate of 1,000 Hz by a 16-bit analog-to-digital converter (USB-6221, National Instruments Inc., Austin, USA), recorded on a computer (Windows 7, Intel Celeron 1007 U at 1.5 GHz with 4 GB RAM) via USB, and accessed using a National Instruments programming interface (NI-DAQmx) for C++.

To ascertain muscular relaxation during passive ankle dorsiflexion motion (joint stiffness measurement) and muscle shear modulus measurement, the EMG activity was recorded from the MG, LG, and Sol. Prior to electrode attachment, the skin was prepared (shaving, rubbing with sandpaper, and cleaning with alcohol). Pre-amplified surface EMG electrodes (electrode shape, parallel bar; electrode size, 1 mm × 10 mm; interelectrode distance, 10 mm; DE-2.1, Delsys Inc.) with band-pass filtering between 20 and 450 Hz (Bagnoli-8 EMG System; Delsys Inc., Boston, MA, United States) were then placed. The electrodes were located just beside the muscle shear modulus measurement location for the MG and LG, and midway between the distal myotendinous junction of the LG and Sol for Sol. The reference electrode was attached to the left medial malleolus.