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Hiroshi Akima - One of the best experts on this subject based on the ideXlab platform.
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Effects of prolonged vibration to Vastus Intermedius Muscle on force steadiness of knee extensor Muscles during isometric force-matching task.
Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology, 2016Co-Authors: Akira Saito, Ryosuke Ando, Hiroshi AkimaAbstract:Afferent inputs from Ia fibers in Muscle spindles are essential for the control of force and prolonged vibration has been applied to Muscle-tendon units to manipulate the synaptic input from Ia afferents onto α-motor neurons. The Vastus Intermedius (VI) reportedly provides the highest contribution to the low-level knee extension torque among the individual synergists of quadriceps femoris (QF). The purpose of the present study was to examine the effect of prolonged vibration to the VI on force steadiness of the QF. Nine healthy men (25.1±4.3years) performed submaximal force-matching task of isometric knee extension for 15s before and after mechanical vibration to the superficial region of VI for 30min. Target forces were 2.5%, 10%, and 30% of maximal voluntary contraction (MVC), and force steadiness was determined by the coefficient of variation (CV) of force. After the prolonged VI vibration, the CV of force at 2.5%MVC was significantly increased, but CVs at 10% and 30%MVCs were not significantly changed. The present study concluded that application of prolonged vibration to the VI increased force fluctuations of the QF during a very low-level force-matching task.
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neuromuscular activation of the Vastus Intermedius Muscle during isometric hip flexion
PLOS ONE, 2015Co-Authors: Akira Saito, Hiroshi AkimaAbstract:Although activity of the rectus femoris (RF) differs from that of the other synergists in quadriceps femoris Muscle group during physical activities in humans, it has been suggested that the activation pattern of the Vastus Intermedius (VI) is similar to that of the RF. The purpose of present study was to examine activation of the VI during isometric hip flexion. Ten healthy men performed isometric hip flexion contractions at 25%, 50%, 75%, and 100% of maximal voluntary contraction at hip joint angles of 90°, 110° and 130°. Surface electromyography (EMG) was used to record activity of the four quadriceps femoris Muscles and EMG signals were root mean square processed and normalized to EMG amplitude during an isometric knee extension with maximal voluntary contraction. The normalized EMG was significantly higher for the VI than for the Vastus medialis during hip flexion at 100% of maximal voluntary contraction at hip joint angles of 110° and 130° (P < 0.05). The onset of VI activation was 230–240 ms later than the onset of RF activation during hip flexion at each hip joint angle, which was significantly later than during knee extension at 100% of maximal voluntary contraction (P < 0.05). These results suggest that the VI is activated later than the RF during hip flexion. Activity of the VI during hip flexion might contribute to stabilize the knee joint as an antagonist and might help to smooth knee joint motion, such as in the transition from hip flexion to knee extension during walking, running and pedaling.
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Effect of interelectrode distance on surface electromyographic signals of Vastus Intermedius Muscle in women and men.
Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology, 2015Co-Authors: Aya Tomita, Kohei Watanabe, Akira Saito, Ryosuke Ando, Hiroshi AkimaAbstract:We previously developed a novel technique to record surface electromyography (EMG) of the Vastus Intermedius (VI) in men. The purpose of the present study was to assess whether this technique can be applied to women in the same way. We measured the subcutaneous fat thickness at the site of electrode placement on VI using ultrasonography. Nine men and ten women performed isometric knee extensions at 25%, 50%, 75%, and 100% of the maximal voluntary contraction. During the tasks, surface EMG signals were recorded from the superficial region of VI with interelectrode distances (IEDs) of 10 mm (IED-10) and 20 mm (IED-20). The subcutaneous fat thickness in women was significantly greater than in men (women: 8.7 ± 2.1 mm; men: 5.6 ± 1.6 mm, p < 0.01). However, the amplitude and frequency of the EMG signal of VI at the different force levels were not affected by IEDs in either sex. These results suggest that surface EMG recording of VI with both IED-10 and IED-20 would be applicable to relatively lean women with a similar sensitivity to that in men.
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knee joint angle affects emg force relationship in the Vastus Intermedius Muscle
Journal of Electromyography and Kinesiology, 2013Co-Authors: Akira Saito, Hiroshi AkimaAbstract:Abstract It is not understood how the knee joint angle affects the relationship between electromyography (EMG) and force of four individual quadriceps femoris (QF) Muscles. The purpose of this study was to examine the effect of the knee joint angle on the EMG–force relationship of the four individual QF Muscles, particularly the Vastus Intermedius (VI), during isometric knee extensions. Eleven healthy men performed 20–100% of maximal voluntary contraction (MVC) at knee joint angles of 90°, 120° and 150°. Surface EMG of the four QF synergists was recorded and normalized by the root mean square during MVC. The normalized EMG of the four QF synergists at a knee joint angle of 150° was significantly lower than that at 90° and 120° ( P P
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the highest antagonistic coactivation of the Vastus Intermedius Muscle among quadriceps femoris Muscles during isometric knee flexion
Journal of Electromyography and Kinesiology, 2013Co-Authors: Akira Saito, Kohei Watanabe, Hiroshi AkimaAbstract:Abstract Although the possibility that the Vastus Intermedius (VI) Muscle contributes to flexion of the knee joint has been suggested previously, the detail of its functional role in knee flexion is not well understood. The purpose of this study was to examine the antagonist coactivation of VI during isometric knee flexion. Thirteen men performed 25–100% of maximal voluntary contraction (MVC) at 90°, 120°, and 150° knee joint angles. Surface electromyography (EMG) of the four individual Muscles in the quadriceps femoris (QF) was recorded and normalized by the EMG signals during isometric knee extension at MVC. Cross-talk on VI EMG signal was assessed based on the median frequency response to selective cooling of hamstring Muscles. Normalized EMG of the VI was significantly higher than that of the other synergistic QF Muscles at each knee joint angle (all P r =0.55–0.85, P
Kohei Watanabe - One of the best experts on this subject based on the ideXlab platform.
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Effect of interelectrode distance on surface electromyographic signals of Vastus Intermedius Muscle in women and men.
Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology, 2015Co-Authors: Aya Tomita, Kohei Watanabe, Akira Saito, Ryosuke Ando, Hiroshi AkimaAbstract:We previously developed a novel technique to record surface electromyography (EMG) of the Vastus Intermedius (VI) in men. The purpose of the present study was to assess whether this technique can be applied to women in the same way. We measured the subcutaneous fat thickness at the site of electrode placement on VI using ultrasonography. Nine men and ten women performed isometric knee extensions at 25%, 50%, 75%, and 100% of the maximal voluntary contraction. During the tasks, surface EMG signals were recorded from the superficial region of VI with interelectrode distances (IEDs) of 10 mm (IED-10) and 20 mm (IED-20). The subcutaneous fat thickness in women was significantly greater than in men (women: 8.7 ± 2.1 mm; men: 5.6 ± 1.6 mm, p < 0.01). However, the amplitude and frequency of the EMG signal of VI at the different force levels were not affected by IEDs in either sex. These results suggest that surface EMG recording of VI with both IED-10 and IED-20 would be applicable to relatively lean women with a similar sensitivity to that in men.
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the highest antagonistic coactivation of the Vastus Intermedius Muscle among quadriceps femoris Muscles during isometric knee flexion
Journal of Electromyography and Kinesiology, 2013Co-Authors: Akira Saito, Kohei Watanabe, Hiroshi AkimaAbstract:Abstract Although the possibility that the Vastus Intermedius (VI) Muscle contributes to flexion of the knee joint has been suggested previously, the detail of its functional role in knee flexion is not well understood. The purpose of this study was to examine the antagonist coactivation of VI during isometric knee flexion. Thirteen men performed 25–100% of maximal voluntary contraction (MVC) at 90°, 120°, and 150° knee joint angles. Surface electromyography (EMG) of the four individual Muscles in the quadriceps femoris (QF) was recorded and normalized by the EMG signals during isometric knee extension at MVC. Cross-talk on VI EMG signal was assessed based on the median frequency response to selective cooling of hamstring Muscles. Normalized EMG of the VI was significantly higher than that of the other synergistic QF Muscles at each knee joint angle (all P r =0.55–0.85, P
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effect of knee joint angle on neuromuscular activation of the Vastus Intermedius Muscle during isometric contraction
Scandinavian Journal of Medicine & Science in Sports, 2011Co-Authors: Kohei Watanabe, Hiroshi AkimaAbstract:The purpose of this study was to compare the relationship between surface electromyography (EMG) and knee joint angle of the Vastus Intermedius Muscle (VI) with the synergistic Muscles in the quadriceps femoris (QF) Muscle group. Fourteen healthy men performed maximal voluntary contractions during isometric knee extension at four knee joint angles from 90°, 115°, 140°, and 165° (180° being full extension). During the contractions, surface EMG was recorded at four Muscle components of the QF Muscle group: the VI, Vastus lateralis (VL), Vastus medialis (VM), and rectus femoris (RF) Muscles. The root mean square of the surface EMG at each knee joint angle was calculated and normalized by that at a knee joint angle of 90° for individual Muscles. The normalized RMS of the VI Muscle was significantly lower than those of the VL and RF Muscles at the knee joint angles of 115° and 165° and those of the VL, VM, and RF Muscles at the knee joint angle of 140° (P<0.05). The present results suggest that the neuromuscular activation of the VI Muscle is regulated in a manner different from the alteration of the knee joint angle compared with other Muscle components of the QF Muscle group.
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Effect of knee joint angle on neuromuscular activation of the Vastus Intermedius Muscle during isometric contraction.
Scandinavian journal of medicine & science in sports, 2011Co-Authors: Kohei Watanabe, Hiroshi AkimaAbstract:The purpose of this study was to compare the relationship between surface electromyography (EMG) and knee joint angle of the Vastus Intermedius Muscle (VI) with the synergistic Muscles in the quadriceps femoris (QF) Muscle group. Fourteen healthy men performed maximal voluntary contractions during isometric knee extension at four knee joint angles from 90°, 115°, 140°, and 165° (180° being full extension). During the contractions, surface EMG was recorded at four Muscle components of the QF Muscle group: the VI, Vastus lateralis (VL), Vastus medialis (VM), and rectus femoris (RF) Muscles. The root mean square of the surface EMG at each knee joint angle was calculated and normalized by that at a knee joint angle of 90° for individual Muscles. The normalized RMS of the VI Muscle was significantly lower than those of the VL and RF Muscles at the knee joint angles of 115° and 165° and those of the VL, VM, and RF Muscles at the knee joint angle of 140° (P
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validity of surface electromyography for Vastus Intermedius Muscle assessed by needle electromyography
Journal of Neuroscience Methods, 2011Co-Authors: Kohei Watanabe, Hiroshi AkimaAbstract:Abstract Recently, a new recording technique for surface electromyography (EMG) of the deeper Muscle component of the quadriceps femoris Muscle group, i.e., Vastus Intermedius (VI) Muscle, from the distal portion of the VI Muscle has been developed; however, the effect of electrode location on EMG signal of the VI Muscle remains unclear. The aim of this study is to compare neuromuscular activation detected at the middle and distal portions of the VI Muscle, in order to clarify whether the surface EMG of the VI Muscle can be used to assess the neuromuscular activation of the entire Muscle. Six healthy men participated in this study. During incremental ramp contraction of isometric knee extension (∼30% of maximal voluntary contraction), needle EMG was recorded from the middle and distal regions of the VI Muscle and surface EMG was performed at the distal region of the VI Muscle. Excellent correlation was observed between needle EMG at the middle and distal regions (r = 0.897–0.984, p
Jacquelin Perry - One of the best experts on this subject based on the ideXlab platform.
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Electromyographic Analysis of Hip and Knee Musculature During Running
The American journal of sports medicine, 1994Co-Authors: William H. Montgomery, Marilyn Pink, Jacquelin PerryAbstract:The purpose of this study was to describe the firing pattern of 11 hip and knee Muscles during running. Thirty recreational runners volunteered to run at 3 different paces with indwelling electromyographic electrodes while being filmed at 100 frames per second. Results demonstrated that medial and lateral vasti Muscles acted together for knee extension during terminal swing and loading response, possibly providing a patella stabilizing role. The Vastus Intermedius Muscle functioned with the other vasti, plus eccentrically controlled knee flexion during swing phase. The rectus femoris Muscle fired with the Vastus Intermedius Muscle and assisted the iliacus Muscle with hip flexion. The hamstrings fired primarily to eccentrically control hip flexion. The adductor magnus, tensor fascia lata, and gluteus maximus Muscles afforded pelvic stabilization while assisting with hip flexion and extension. Forward propulsion was provided mainly by hip flexion and knee extension, which is contrary to the view that posterior calf Muscles provide propulsion during toe off. Faster running paces lead to increased activity in the Muscles. This may lead to more injuries, primarily in the Muscles that were contracting eccentrically.
George Panayiotakis - One of the best experts on this subject based on the ideXlab platform.
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The ultrasonographic measurement of Muscle thickness in sarcopenia. A prediction study.
European journal of physical and rehabilitation medicine, 2020Co-Authors: Nikolaos Barotsis, Angeliki Galata, Anastasia C. Hadjiconstanti, George PanayiotakisAbstract:BACKGROUND Sarcopenia is a common disease in the elderly. Although extensive research has been conducted on Muscle mass and quality assessment tools, there are still certain drawbacks preventing their universal use. AIM The aim of this study was the evaluation of the thickness of head, neck, upper and lower limb Muscles measured with ultrasonography, as a potential predictory tool in sarcopenia. DESIGN Prediction study. SETTING The Outpatient Sarcopenia Clinic of the Rehabilitation Department of the University Hospital of Patras. POPULATION Ninety-four individuals (27 men and 67 women) with a mean age of 75.6 years (SD=6.6), referred for sarcopenia screening, participated in this study. METHODS The Muscle thickness was measured with transverse and longitudinal ultrasound scans bilaterally. RESULTS The thickness of the geniohyoid and medial head of gastrocnemius Muscle in all ultrasound sections, and the thickness of the rectus femoris and Vastus Intermedius Muscle, in specific sections, was found to be significantly decreased in patients with sarcopenia (P
William H. Montgomery - One of the best experts on this subject based on the ideXlab platform.
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Electromyographic Analysis of Hip and Knee Musculature During Running
The American journal of sports medicine, 1994Co-Authors: William H. Montgomery, Marilyn Pink, Jacquelin PerryAbstract:The purpose of this study was to describe the firing pattern of 11 hip and knee Muscles during running. Thirty recreational runners volunteered to run at 3 different paces with indwelling electromyographic electrodes while being filmed at 100 frames per second. Results demonstrated that medial and lateral vasti Muscles acted together for knee extension during terminal swing and loading response, possibly providing a patella stabilizing role. The Vastus Intermedius Muscle functioned with the other vasti, plus eccentrically controlled knee flexion during swing phase. The rectus femoris Muscle fired with the Vastus Intermedius Muscle and assisted the iliacus Muscle with hip flexion. The hamstrings fired primarily to eccentrically control hip flexion. The adductor magnus, tensor fascia lata, and gluteus maximus Muscles afforded pelvic stabilization while assisting with hip flexion and extension. Forward propulsion was provided mainly by hip flexion and knee extension, which is contrary to the view that posterior calf Muscles provide propulsion during toe off. Faster running paces lead to increased activity in the Muscles. This may lead to more injuries, primarily in the Muscles that were contracting eccentrically.