論文 Determination of subset models for predicting vertical centre of mass position during front crawl in male swimmers. Journal of sports sciences,:1-9 2023(May 19) Author:Sohei Washino; Akihiko Murai; Hirotoshi Mankyu; Yasuhide Yoshitake Abstract:We attempted to find a subset model that would allow robust prediction of a swimmer's vertical body position during front crawl with fewer markers, which can reduce extra drag and time-consuming measurements. Thirteen male swimmers performed a 15-metre front crawl either with three different lung-volume levels or various speeds, or both, without taking a breath with 36 reflective markers. The vertical positions of the centre of mass (CoM) and four representative landmarks in the trunk segment over a stroke cycle were calculated using an underwater motion-capture system. We obtained 212 stroke cycles across trials and analysed the vertical position derived from 15 patterns as candidates for the subset models. Unconstrained optimisation minimises the root-mean-square error between the vertical CoM position and each subset model. The performance evaluated from the intra-class correlation coefficient (ICC) and weight parameters of each subset model were detected from the mean values across five-fold cross-validation. The subset model with four markers attached to the trunk segment showed good reliability (ICC: 0.776 ± 0.019). This result indicates that the subset model with few markers can robustly predict a male swimmer's vertical CoM position during front crawl under a wide range of speeds from 0.66 to 1.66 m · s-1.
Greater task difficulty during unilateral motor tasks changes intracortical inhibition and facilitation in the ipsilateral primary motor cortex in young men Neuroscience Letters,:137293-137293 2023(May) Author:Hironori Watanabe; Shigehiko Ogoh; Naokazu Miyamoto; Hiroaki Kanehisa; Yasuhide Yoshitake
The projected frontal area and its components during front crawl depend on lung volume. Scandinavian journal of medicine & science in sports,32(12):1724-1737 2022(Sep. 10) Author:Sohei Washino; Akihiko Murai; Hirotoshi Mankyu; Futoshi Ogita; Hiroaki Kanehisa; Yasuhide Yoshitake Abstract:We examined the influence of lung volume on the vertical body position, trunk inclination, and projected frontal area (PFA) during swimming and the inter-relationships among these factors. Twelve highly trained male swimmers performed a 15 m front crawl with sustained maximal inspiration (INSP), maximal expiration (EXP), and intermediate (MID) at a target velocity of 1.20 m·s-1 . Using our developed digital human model, which allows inverse kinematics calculations by fitting individual body shapes measured with a three-dimensional photonic image scanner to individually measured underwater motion capture data, vertical center of mass (CoM) position, trunk inclination, and PFA were calculated for each complete stroke cycle. In particular, the PFA was calculated by automatic processing of a series of parallel frontal images obtained from a reconstructed digital human model. The vertical CoM position was higher with a larger lung-volume level (P < 0.01). The trunk inclination was smaller in INSP and MID than in EXP (P < 0.01). PFA was smaller with a larger lung-volume level (P < 0.01). Additionally, there was a significant interaction of vertical CoM position and trunk inclination with PFA (P = 0.006). There was a negative association between PFA and vertical CoM position, and a positive association between PFA and trunk inclination less than the moderate vertical CoM position (each P < 0.05). These results obtained using our methodology indicate that PFA decreases with increasing lung volume due to an increase in vertical CoM position, and additionally due to a decrease in trunk inclination at low-to-moderate lung-volume levels.
Vertical body position during front crawl increases linearly with swimming velocity and the rate of its increase depends on individual swimmers Sports Biomechanics,:1-13 2022(May 16) Author:Sohei Washino; Yasuhide Yoshitake; Hirotoshi Mankyu; Akihiko Murai
Lower lung-volume level induces lower vertical center of mass position and alters swimming kinematics during front-crawl swimming Journal of Biomechanics 2021(Apr.) Author:Washino S; Murai A; Mankyu H; Ogita F; Kanehisa H; Yoshitake Y
Reconstruction of net force fluctuations from surface EMGs of multiple muscles in steady isometric plantarflexion Experimental Brain Research,239(2):601-612 2021(Feb.) Author:Suzuki R; Kanehisa H; Washino S; Watanabe H; Shinohara M; Yoshitake Y Abstract:The purposes of this study were to clarify if force fluctuations during steady multi-muscle contractions have a temporal correlation with a low-frequency component of rectified surface EMG (rEMG) in the involved muscles and collection of that component across muscles allows for the reconstruction of force fluctuations across a wide range of contraction intensities. Healthy young men (n = 15) exerted steady isometric plantarflexion force at 5-60% of maximal force. Surface EMG was recorded from the medial and lateral gastrocnemii, soleus, peroneus longus, abductor hallucis, and tibialis anterior muscles. The cross-correlation function (CCF) between plantarflexion force fluctuations and low-pass filtered rEMG in each muscle was calculated for 8 s. To reconstruct force fluctuations from rEMGs, the product of rEMG and an identified constant factor were summed across muscles with time-lag compensation for electro-mechanical delay. A distinct peak of the CCF was found between plantarflexion force fluctuations and rEMG in most cases except for the tibialis anterior. The CCF peak was greatest in the medial gastrocnemius and soleus. Reconstructed force from rEMGs was temporally correlated with measured force fluctuations across contraction intensities (average CCF peak: r = 0.65). The results indicate that individual surface rEMG has a low-frequency component that is temporally correlated with net force fluctuations during steady multi-muscle contractions and contributes to the reconstruction of force fluctuations across a wide range of contraction intensities. It suggests a potential applicability of individual surface EMGs for identifying the contributing muscles to controlling or disturbing isometric steady force in multi-muscle contractions.
Association between Changes in Swimming Velocity, Vertical Center of Mass Position, and Projected Frontal Area during Maximal 200-m Front Crawl ,49(1) 2020(Jun.) Author:Sohei Washino; Akihiko Murai; Hirotoshi Mankyu; Yasuhide Yoshitake
Fine-wire recordings of flexor hallucis brevis motor units up to maximal voluntary contraction reveal a flexible, non-rigid mechanism for force control Journal of Neurophysiology,:-in press 2020(Apr.) Author:Aeles J, Kelly L.A, Yoshitake Y, Cresswell A.G.
Swimming performance is reduced by reflective markers intended for the analysis of swimming kinematics. ,91:109-113 2019(Jun.) Author:Washino S; Mayfield DL; Lichtwark GA; Mankyu H; Yoshitake Y
Repeated sit-to-stand exercise enhances muscle strength and reduces lower body muscular demands in physically frail elders. Exp Gerontol in press 2019(Jan.) Author:Fujita E; Taaffe DR; Yoshitake Y; Kanehisa H
Effects of inspiratory muscle strength and inspiratory resistance on neck inspiratory muscle activation during controlled inspirations Experimental Physiology,in press 2019 Author:Washino S; Mankyu H; Kanehisa H; Mayfield DL; Cresswell AG; Yoshitake Y
Corticospinal Excitability During Actual and Imaginary Motor Tasks of Varied Difficulty Neuroscience,391(1):81-90 2018(Nov.) Author:Watanabe H; Mizuguchi N; Mayfield DL; Yoshitake Y
Mechanical interaction between neighboring muscles in human upper limb: Evidence for epimuscular myofascial force transmission in humans Journal of Biomechanics,74(74):150-155 2018(Jun. 06) Author:Yasuhide Yoshitake; Daiki Uchida; Kosuke Hirata; Dean L. Mayfield; Hiroaki Kanehisa Abstract:To confirm the existence of epimuscular myofascial force transmission in humans, this study examined if manipulating joint angle to stretch the muscle can alter the shear modulus of a resting adjacent muscle, and whether there are regional differences in this response. The biceps brachii (BB: manipulated muscle) and the brachialis (BRA: resting adjacent muscle) were deemed suitable for this study because they are neighboring, yet have independent tendons that insert onto different bones. In order to manipulate the muscle length of BB only, the forearm was passively set at supination, neutral, and pronation positions. For thirteen healthy young adult men, the shear modulus of BB and BRA was measured with shear-wave elastography at proximal and distal muscle regions for each forearm position and with the elbow joint angle at either 100° or 160°. At both muscle regions and both elbow positions, BB shear modulus increased as the forearm was rotated from a supinated to pronated position. Conversely, BRA shear modulus decreased as function of forearm position. The effect of forearm position on shear modulus was most pronounced in the distal muscle region when the elbow was at 160°. The observed alteration of shear modulus of the resting adjacent muscle indicates that epimuscular myofascial force transmission is present in the human upper limb. Consistent with this assertion, we found that the effect of muscle length on shear modulus in both muscles was region-dependent. Our results also suggest that epimuscular myofascial force transmission may be facilitated at stretched muscle lengths.
Robotic finger perturbation training improves finger postural steadiness and hand dexterity. Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology,38:208-214 2018(Feb.) Author:Yasuhide Yoshitake; Atsutoshi Ikeda; Minoru Shinohara Abstract:The purpose of the study was to understand the effect of robotic finger perturbation training on steadiness in finger posture and hand dexterity in healthy young adults. A mobile robotic finger training system was designed to have the functions of high-speed mechanical response, two degrees of freedom, and adjustable loading amplitude and direction. Healthy young adults were assigned to one of the three groups: random perturbation training (RPT), constant force training (CFT), and control. Subjects in RPT and CFT performed steady posture training with their index finger using the robot in different modes: random force in RPT and constant force in CFT. After the 2-week intervention period, fluctuations of the index finger posture decreased only in RPT during steady position-matching tasks with an inertial load. Purdue pegboard test score improved also in RPT only. The relative change in finger postural fluctuations was negatively correlated with the relative change in the number of completed pegs in the pegboard test in RPT. The results indicate that finger posture training with random mechanical perturbations of varying amplitudes and directions of force is effective in improving finger postural steadiness and hand dexterity in healthy young adults.
Automatic analysis of ultrasound shear-wave elastography in skeletal muscle without non-contractile tissue contamination. International Journal of Intelligent Robotics and Applications. International Journal of Intelligent Robotics and Applications.,2:209-225 2018 Author:Brown E; Yoshitake Y; Shinohara M; Ueda J
Estimation of vertical COG position by underwater motion-capture system with small number of markers during swimming The XIIIth International Symposium on Biomechanics and Medicine in Swimming,:182-186 2018 Author:Sohei Washino; Hirotoshi Mankyu; Yasuhide Yoshitake
Neck inspiratory muscle activation patterns during well-controlled inspiration EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY,117(10):2085-2097 2017(Oct.) Author:Sohei Washino; Hiroaki Kanehisa; Yasuhide Yoshitake Abstract:Purpose Surprisingly, the activation characteristics of the neck inspiratory muscles as a function of key inspiratory mechanical parameters have yet to be demonstrated experimentally under well-controlled conditions. This study aimed to elucidate the muscle activation patterns of the neck inspiratory muscles by strictly controlling flow rate and lung volume.
Methods Thirteen healthy subjects matched their inspiratory flow rate at approximately 20-100% of peak flow rate (PFR) as steady as possible during inspiration. Amplitude of surface electromyogram (EMG) of the sternocleidomastoid (SCM) and scalene were calculated for every increase in %PFR over a duration corresponding to an increase in lung volume by 10% of forced vital capacity (FVC), as well as for every 5% increment of FVC over a point corresponding to an increase in flow rate by 20%PFR to determine the %PFR-EMG and %FVC-EMG relations, respectively.
Results Regression analyses showed that EMGs of the neck inspiratory muscles exponentially increased with increase in %PFR and their associated variables which reflect recruitment onset when increasing flow rate increased with increasing %FVC. In %FVC-EMG relation, a linear regression analysis showed positive slope at all %PFR and positive y-intercept at 80% PFR.
Conclusions The main new finding is that the neck inspiratory muscle activities increase with flow rate as well as lung volume. The positive y-intercept of the %FVC-EMG relation at higher %PFR indicates that the neck inspiratory muscles are always activated even when lung volume level is low, implying that SCM is not necessarily an "accessory" muscle as described in previous observations.
Unintended activity in homologous muscle during intended unilateral contractions increases with greater task difficulty EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY,117(10):2009-2019 2017(Oct.) Author:Hironori Watanabe; Hiroaki Kanehisa; Yasuhide Yoshitake Abstract:Purpose The present study aimed to examine (1) the effect of task difficulty on unintended muscle activation (UIMA) levels in contralateral homologous muscle, (2) the difference between young and old adults in degree of UIMA with respect to task difficulty, and (3) temporal correlations between intended and contralateral unintended muscle activity at low frequency during unilateral intended force-matching tasks.
Methods Twelve young (21.8 +/- 2.4 years) and twelve old (69.9 +/- 5.3 years) adult men performed steady isometric abductions with the left index finger at 20-80% of maximal voluntary contraction force. Two task difficulties were set by adjusting the spacing between two bars centered about the target force used for visual feedback on a monitor. The amplitude of surface electromyogram (aEMG) for both hands was calculated and normalized with respect to the maximal value. To determine if oscillations between intended and unintended muscle activities were correlated, cross-correlation function (CCF) of rectified EMG for both hands at low frequency was calculated for samples deemed adequate.
Results The unintended aEMG (right hand) had significant main effects in task difficulty, age, and target force (all P < 0.05) without any interactions. Distinct significant peaks in CCF (0.38 on average, P < 0.05) with small time lags were present between rectified EMGs of intended and unintended muscles in 14 of the 17 samples.
Conclusions The current results indicate that UIMA increases with greater task difficulty regardless of age, and temporal correlations exist between intended and contralateral unintended muscle activities at low frequency.
Correlated EMG Oscillations between Antagonists during Cocontraction in Men MEDICINE AND SCIENCE IN SPORTS AND EXERCISE,49(3):538-548 2017(Mar.) Author:Yasuhide Yoshitake; Hiroaki Kanehisa; Minoru Shinohara Abstract:Purpose: The purpose of this study was to determine the modulation of common low-frequency oscillations in pools of motor units across antagonistic muscles because of the difference in the activation level of pools of spinal motor neurons and the presence of neuromuscular fatigue during intended cocontraction. Methods: Ten healthy young men (21.8 +/- 1.5 yr) performed intended steady cocontractions of elbow flexors and extensors at maximal and a submaximal (10% of maximal EMG) effort. The submaximal cocontraction was repeated after sustained maximal contraction of elbow flexors. Surface EMG was recorded from the biceps brachii and triceps brachii muscles. Correlated EMG oscillations between the antagonistic muscles were quantified by the cross-correlation function (CCF) using rectified EMG for the < 3-Hz band and using rectified and unrectified EMG for the 3- to 15-Hz bands. Results: The positive CCF peak in rectified EMG < 3 Hz with little time lag (i.e., in-phase oscillations) during submaximal cocontraction was smaller compared with maximal cocontraction, but increased after the sustained contraction. In the 3- to 15-Hz band of both unrectified and rectified EMG, a negative CCF peak (i.e., out-of-phase oscillations) during submaximal cocontraction was smaller compared with maximal cocontraction but increased after the sustained contraction. Across subjects, the degree of reduction in maximal EMG amplitude after the sustained contraction was correlated with the amount of change in the CCF peak in < 3 Hz but not in the 3- to 15-Hz band. Conclusion: The results indicate that 1) in-phase < 3-Hz and out-of-phase 3-15-Hz correlated EMG oscillations between antagonistic muscles occur during intended cocontraction, and 2) the magnitude of these correlated oscillations increases with the activation level of pools of spinal motor neurons and neuromuscular fatigue.
THE SKIN ACTS TO MAINTAIN MUSCLE SHEAR MODULUS ULTRASOUND IN MEDICINE AND BIOLOGY,42(3):674-682 2016(Mar.) Author:Yasuhide Yoshitake; Naokazu Miyamoto; Keigo Taniguchi; Masaki Katayose; Hiroaki Kanehisa Abstract:It is not clear how the tissues covering the skeletal muscles affect the muscles' mechanical properties. The main purpose of this study was to examine changes in muscle shear modulus as a representative mechanical property of muscle with and without the covering tissues of skin and epimysium (fascia). Shear modulus of the medial gastrocnemius (MG) muscle was determined using ultrasound shear-wave elastography in the Thiel's embalmed cadavers under three different conditions: original (intact cadavers), removal of the skin on the MG and subsequent removal of the epimysium. Muscle shear modulus significantly decreased by 50% after removal of the skin, whereas no additional changes in shear modulus were observed after subsequent removal of the epimysium. This study suggests that the skin is a main contributor for maintaining the muscle mechanical properties among tissues covering the skeletal muscle. (E-mail: y-yoshi@nifs-k.ac.jp) (C) 2016 World Federation for Ultrasound in Medicine & Biology.
Unilateral horizontal and lateral jump performances are associated with the competitive level of collegiate soccer players. Gazz Med Ital,175(12):528-535 2016 Author:Aoki T; Takai Y; Yoshitake Y; Kanehisa H
Validity of Measurement of Shear Modulus by Ultrasound Shear Wave Elastography in Human Pennate Muscle PLOS ONE,10(4):e0124311 2015(Apr.) Author:Naokazu Miyamoto; Kosuke Hirata; Hiroaki Kanehisa; Yasuhide Yoshitake Abstract:Ultrasound shear wave elastography is becoming a valuable tool for measuring mechanical properties of individual muscles. Since ultrasound shear wave elastography measures shear modulus along the principal axis of the probe (i.e., along the transverse axis of the imaging plane), the measured shear modulus most accurately represents the mechanical property of the muscle along the fascicle direction when the probe's principal axis is parallel to the fascicle direction in the plane of the ultrasound image. However, it is unclear how the measured shear modulus is affected by the probe angle relative to the fascicle direction in the same plane. The purpose of the present study was therefore to examine whether the angle between the principal axis of the probe and the fascicle direction in the same plane affects the measured shear modulus. Shear modulus in seven specially-designed tissue-mimicking phantoms, and in eleven human in-vivo biceps brachii and medial gastrocnemius were determined by using ultrasound shear wave elastography. The probe was positioned parallel or 20 degrees obliquely to the fascicle across the B-mode images. The reproducibility of shear modulus measurements was high for both parallel and oblique conditions. Although there was a significant effect of the probe angle relative to the fascicle on the shear modulus in human experiment, the magnitude was negligibly small. These findings indicate that the ultrasound shear wave elastography is a valid tool for evaluating the mechanical property of pennate muscles along the fascicle direction.
Muscle shear modulus measured with ultrasound shear-wave elastography across a wide range of contraction intensity. Muscle & nerve,50(1):103-13 2014(Jul.) Author:Yasuhide Yoshitake; Yohei Takai; Hiroaki Kanehisa; Minoru Shinohara Abstract:INTRODUCTION: In this study we examine the repeatability of measuring muscle shear modulus using ultrasound shear-wave elastography between trials and between days, and the association between shear modulus and contraction intensity over a wide range of intensities. METHODS: Shear modulus of the biceps brachii was determined using ultrasound shear-wave elastography during static elbow flexion (up to 60% of maximal contraction) in healthy young adults. RESULTS: The correspondence of shear modulus was confirmed in phantoms between the manufacturer-calibrated values and the shear-wave elastography values. The intraclass correlation coefficient of muscle shear modulus was high: 0.978 between trials and 0.948 between days. Shear modulus increased linearly with elbow flexion torque across contraction intensity, and its slope was associated negatively with muscle strength. CONCLUSIONS: Muscle shear modulus measured with ultrasound shear-wave elastography may be useful for inferring muscle stiffness across a wide range of contraction intensity. In addition, it has high repeatability between trials and between days.
Neuromuscular adaptations following 12-week maximal voluntary co-contraction training. European journal of applied physiology,114(4):663-73 2014(Apr.) Author:Sumiaki Maeo; Yasuhide Yoshitake; Yohei Takai; Tetsuo Fukunaga; Hiroaki Kanehisa Abstract:PURPOSE: The present study examined neuromuscular adaptations following 12-week maximal voluntary co-contraction training. METHODS: Sixteen young men were allocated to training (TG, n = 9) or control (CG, n = 7) group. TG conducted a training program (3 days/week), which consisted of 4-s maximal voluntary contractions of elbow flexors and extensors by simultaneously contracting both muscle groups at 90° of the elbow joint, followed by 4-s muscle relaxation (10 repetitions/set, 5 sets/day) for 12 weeks. In addition to the muscle thicknesses of elbow flexors and extensors, the torque and electromyograms (EMGs) of the two muscle groups during isometric maximal voluntary contraction (MVC) were determined before (Pre), after 4 weeks, and 12 weeks of intervention. RESULTS: After intervention, CG showed no significant changes in all measured variables. In TG, MVC torque significantly increased in both elbow flexors (+13 % at 4 weeks and +15 % at 12 weeks) and extensors (+27 % at 4 weeks and +46 % at 12 weeks) from Pre. Muscle thickness also significantly increased in both elbow flexors (+4 %) and extensors (+4 %) at 12 weeks. Agonist EMG activities during MVC significantly increased in both elbow flexors (+31 % at 4 weeks and +44 % at 12 weeks) and extensors (+27 % at 4 weeks and +40 % at 12 weeks), without changes in antagonist involuntary coactivation level in both muscle groups. CONCLUSION: These results indicate that maximal voluntary co-contraction is applicable as a training modality for increasing the size and strength of antagonistic muscle pairs without increasing involuntary coactivation level.
Effect of Short-term Maximal Voluntary Co-contraction Training on Neuromuscular Function INTERNATIONAL JOURNAL OF SPORTS MEDICINE,35(2):125-134 2014(Feb.) Author:S. Maeo; Y. Yoshitake; Y. Takai; T. Fukunaga; H. Kanehisa Abstract:The present study aimed to examine the effect of short-term training utilizing voluntary co-contraction with maximal efforts. 23 healthy young men (training group: TG, n=13; control group: CG, n=10) participated in this study. TG conducted a 4-week training program (3 days/week), which consisted of 4s simultaneous maximal voluntary contractions of elbow flexors and extensors at 90 degrees of the elbow joint, followed by 4s muscle relaxation (10 repetitions/set, 5 sets/day). Before and after the intervention, maximal voluntary isometric and isokinetic torques and the muscle thicknesses of the elbow flexors and extensors were determined. The electromyograms (EMGs) of the 2 muscle groups during isometric maximal voluntary contraction (MVC) were also recorded. After the intervention, CG did not show any significant changes in all measured variables. In TG, significant increases were found in the agonist EMG activities during MVC, and maximal isometric and isokinetic torques of the elbow flexors and extensors, without significant changes in the muscle thicknesses and involuntary coactivation levels during MVC. The current results indicate that the training mode with maximal voluntary co-contraction is effective for improving the force-generating capabilities of the exercising muscles, without any increases in the level of involuntary coactivation during MVC.
Oscillations in motor unit discharge are reflected in the low-frequency component of rectified surface EMG and the rate of change in force EXPERIMENTAL BRAIN RESEARCH,231(3):267-276 2013(Nov.) Author:Yasuhide Yoshitake; Minoru Shinohara Abstract:Common drive to a motor unit (MU) pool manifests as low-frequency oscillations in MU discharge rate, producing fluctuations in muscle force. The aim of the study was to examine the temporal correlation between instantaneous MU discharge rate and rectified EMG in low frequencies. Additionally, we attempted to examine whether there is a temporal correlation between the low-frequency oscillations in MU discharge rate and the first derivative of force (dF/dt). Healthy young subjects produced steady submaximal force with their right finger as a single task or while maintaining a pinch-grip force with the left hand as a dual task. Surface EMG and fine-wire MU potentials were recorded from the first dorsal interosseous muscle in the right hand. Surface EMG was band-pass filtered (5-1,000 Hz) and full-wave rectified. Rectified surface EMG and the instantaneous discharge rate of MUs were smoothed by a Hann-window of 400 ms duration (equivalent to 2 Hz low-pass filtering). In each of the identified MUs, the smoothed MU discharge rate was positively correlated with the rectified-and-smoothed EMG as confirmed by the distinct peak in cross-correlation function with greater values in the dual task compared with the single task. Additionally, the smoothed MU discharge rate was temporally correlated with dF/dt more than with force and with rectified-and-smoothed EMG. The results indicated that the low-frequency component of rectified surface EMG and the first derivative of force provide temporal information on the low-frequency oscillations in the MU discharge rate.
Low-frequency component of rectified EMG is temporally correlated with force and instantaneous rate of force fluctuations during steady contractions MUSCLE & NERVE,47(4):577-584 2013(Apr.) Author:Yasuhide Yoshitake; Minoru Shinohara Abstract:Introduction: The usefulness of surface EMG for assessing motor output variability during steady contraction is unclear. The purpose of this study was to examine the temporal correlation in signal characteristics between low-frequency components of full-wave rectified EMG (with or without high-pass filtering before rectification) and force fluctuations or the instantaneous rate of force fluctuations (dF/dt) during steady contractions. Methods: Fourteen young adults produced steady force with the first dorsal interosseus muscle at various intensities. Cross-correlation functions were calculated between the following signals: <5 Hz: force, dF/dt, and rectified EMG with or without high-pass filtering at 300 Hz before rectification. Results: Rectified EMG correlated better with dF/dt compared with force itself, and high-pass filtering of interference EMG before rectification improved the temporal correlation. Conclusions: The low-frequency component of rectified EMG following high-pass filtering may provide temporal information on the instantaneous rate of force fluctuations during steady contractions. Muscle Nerve 47: [?show $1534v][?show $1535v], 2013
COMPARISON OF ULTRASOUND MUSCLE STIFFNESS MEASUREMENT AND ELECTROMYOGRAPHY TOWARDS VALIDATION OF AN ALGORITHM FOR INDIVIDUAL MUSCLE CONTROL ASME 2013 DYNAMIC SYSTEMS AND CONTROL CONFERENCE, VOL 2 2013 Author:Ellenor Brown; Kazuya Aomoto; Atsutoshi Ikeda; Tsukasa Ogasawara; Yasuhide Yoshitake; Minoru Shinohara; Jun Ueda Abstract:The ability to control individual muscle activity is widely applicable in clinical diagnostics, training, and rehabilitation. Inducing muscle patterns that amplify abnormal muscle coordination can assist with early diagnosis of neuromuscular disorders. Individual muscle control also allows for targeted exercise of muscles weakened by disease, injury, or disuse. The goals of this research are to test a system for individual muscle control and introduce the use of muscle ultrasound as an alternative to electromyography (EMG). The system integrates a computational model of the right upper extremity with a robotic manipulator to predict and control muscle activity. To test the system, subjects gripped the manipulator and isometrically resisted loads applied to the hand. Muscle activity was measured via EMG and ultrasound. The system was able to induce the desired direction of muscle activity change but with limited precision. EMG measurement appeared susceptible to error due to crosstalk in the forearm.
Knee extensor strength is associated with Mini-Mental State Examination scores in elderly men. European journal of applied physiology,112(5):1945-53 2012(May) Author:Hiroki Nakamoto; Yasuhide Yoshitake; Yohei Takai; Hiroaki Kanehisa; Takahiro Kitamura; Masashi Kawanishi; Shiro Mori Abstract:The present study examined whether the strength capability of knee extensor muscles is associated with global cognitive function, assessed by Mini-Mental State Examination (MMSE), in non-disabled elderly men. Isometric torques during maximal voluntary knee extension, plantar flexion, and elbow flexion and MMSE scores were determined in 39 non-disabled men aged 61-79 years and used for the cross-sectional analysis examining the associations among the measured variables. Moreover, 27 of the subjects participated in a training program consisted of body mass-based exercises (sitting down onto and standing up from a chair, hip joint extension and flexion, calf raises, side leg raises, and trunk flexion and extension) 6 days a week for 3 months. Isometric torques and MMSE scores were determined after the intervention. Among the data before intervention, only knee extension torque (KET) and KET relative to body mass (KET/BM) significantly correlated to the MMSE scores: r = 0.579 (P < 0.0001) for KET and r = 0.520 (P < 0.001) for KET/BM. After the intervention, KET and KET/BM increased significantly, but MMSE score did not. However, the absolute change in MMSE scores was significantly associated with that in KET (r = 0.381, P < 0.05) and KET/BM (r = 0.422, P < 0.05). These findings indicate that the strength capability of knee extensors is associated with global cognitive function in non-disabled elderly men, and provide a new perspective to a general concept that exercises strengthening knee extensor muscles should be included in resistance training programs for elderly individuals.
Association between Knee Extensor Strength and EMG Activities during Squat Movement MEDICINE AND SCIENCE IN SPORTS AND EXERCISE,43(12):2328-2334 2011(Dec.) Author:Eiji Fujita; Hiroaki Kanehisa; Yasuhide Yoshitake; Tetsuo Fukunaga; Hidetsugu Nishizono Abstract:FUJITA, E., H. KANEHISA, Y. YOSHITAKE, T. FUKUNAGA, and H. NISHIZONO. Association between Knee Extensor Strength and EMG Activities during Squat Movement. Med. Sci. Sports Exerc., Vol. 43, No. 12, pp. 2328-2334, 2011. Purpose: The present study aimed to clarify how the force-generating capability of quadriceps femoris (QF) is associated to its surface EMG activity during a body mass-based squat movement. Methods: Isometric knee extension torque (KET) during maximal voluntary contraction and EMG activities of the rectus femoris and vastus lateralis muscles during a body mass-based squat movement were determined in 53 men and 48 women age 19-90 yr, including 18 frail elderly persons who used the long-term care insurance system. The rectified EMG signals during the squat movement were averaged and normalized as the relative value (%EMG(max)) to that during maximal voluntary contraction. The %EMG(max) values for rectus femoris and vastus lateralis were averaged and used as an index representing the level of muscular activities of QF during the squat movement (QF %EMG(max)). Results: QF %EMG(max) was nonlinearly related to KET relative to body mass (KET/BM). Linear piecewise continuous regression analysis showed that there was a breakpoint of 1.9 N.m.kg(-1) in the relationship between the two variables. In individuals with KET/BM less than 1.9 N.m.kg(-1), QF %EMG(max) rapidly increased as KET/BM decreased. Conclusions: The current results indicate that the activity level of QF during a body mass-based squat movement is influenced by its force generation capability. For individuals with a KET/BM less than 1.9 N.m.kg(-1), body mass-based squat movement is considered to be a fairly high-intensity exercise. The breakpoint of 1.9 N.m.kg(-1) may be assumed to be a threshold level of knee extensor strength, which should be maintained for performing the activities of daily living without great difficulty.
Body Mass-Based Exercise in Middle-Aged and Older Women INTERNATIONAL JOURNAL OF SPORTS MEDICINE,32(12):924-928 2011(Dec.) Author:Y. Yoshitake; Y. Takai; T. Kitamura; M. Kawanishi; H. Kanehisa Abstract:The present study examined whether the degree to which muscle strength is improved by a body mass-based home exercise program in middle-aged and older women depends on the force-generating capabilities of the muscles prior to the intervention. 75 women (53-76 years) voluntarily participated in a circuit training program consisting of 5 exercises (16 repetitions/exercise, 2 or 3 circuits/day) using only body mass as resistance for 3 months. The subjects performed the training program 6 days a week in their own home and once a week in a local gym. Before and after intervention, isometric torques during maximal voluntary knee extension (KET) and plantar flexion (PFT) were determined and expressed relative to body mass (KET/BM and PFT/BM, respectively). KET/BM and PFT/BM increased significantly after intervention, and their relative changes were negatively correlated to the absolute values before intervention. Most of the subjects whose KET/BM and PFT/BM values before intervention were greater than 2.8Nm/kg and 1.7Nm/kg, respectively, did not show increases in strength after intervention. Thus, although body mass-based exercise at home is effective in improving lower limb strength in middle-aged and older women, the magnitude of the improvement is influenced by the force-generating capability before intervention.
Muscle Deoxygenation during Sustained and Intermittent Isometric Exercise in Hypoxia MEDICINE AND SCIENCE IN SPORTS AND EXERCISE,42(7):1269-1278 2010(Jul.) Author:Keisho Katayama; Yasuhide Yoshitake; Kohei Watanabe; Hiroshi Akima; Koji Ishida Abstract:KATAYAMA, K., Y. YOSHITAKE, K. WATANABE, H. AKIMA, and K. ISHIDA. Muscle Deoxygenation during Sustained and Intermittent Isometric Exercise in Hypoxia. Med. Sci. Sports Exerc., Vol. 42, No. 7, pp. 1269-1278, 2010. Purpose: It is reported that the rate of locomotor muscle fatigue development during intermittent isometric exercise in hypoxia is accelerated compared with normoxia. In contrast, when sustained isometric contractions are used, some studies do not show any effect of hypoxia on fatigue development. Increased intramuscular pressure during sustained isometric exercise causes substantial and sustained ischemia, even in normoxia. Therefore, we hypothesized that the difference in muscle deoxygenation between normoxia and hypoxia would be small during sustained exercise compared with intermittent exercise and that this may contribute to the inconsistent findings. Methods: Subjects performed sustained and intermittent isometric, unilateral, and submaximal knee-extension exercises (60% maximal voluntary contraction to exhaustion) while breathing normoxic (inspired O(2) fraction = 0.21) or hypoxic gas mixtures (inspired O(2) fraction = 0.10-0.12). Muscle oxygenation (deoxyhemoglobin/myoglobin and tissue oxygenation index) using near-infrared spectroscopy and surface EMG were measured from the left vastus lateralis. Results: During intermittent isometric exercise in hypoxia, increases in deoxyhemoglobin/myoglobin and reductions of tissue oxygenation index were larger (P < 0.05) than those in normoxia. The rate of rise in integrated EMG during intermittent exercise was accelerated (P < 0.05) in hypoxia. In contrast, there were no significant differences in changes in near-infrared spectroscopy variables and integrated EMG during sustained isometric exercise between normoxia and hypoxia. Conclusions: These results suggest that muscle deoxygenation is exaggerated during intermittent isometric exercise in hypoxia compared with normoxia, whereas during sustained isometric exercise, the extent of muscle deoxygenation is the same between normoxia and hypoxia. The different extent of muscle deoxygenation during sustained and intermittent isometric exercise in normoxia and hypoxia could affect muscle fatigability, which results from the varied rate of accumulation of metabolites.
Alterations in Synergistic Muscle Activation Impact Fluctuations in Net Force MEDICINE AND SCIENCE IN SPORTS AND EXERCISE,41(1):191-197 2009(Jan.) Author:Minoru Shinohara; Yasuhide Yoshitake; Motoki Kouzaki Abstract:SHINOHARA, M., Y. YOSHITAKE, and M. KOUZAKI. Alterations in Synergistic Muscle Activation Impact Fluctuations in Net Force. Med. Sci. Sports Exerc., Vol. 41, No. 1, pp. 191-197 2009. Net muscle force recorded during voluntary contractions with multiple agonist muscles is the summated result of individual muscle forces. The purpose of this article is to synthesize recent findings from several studies oil the modulations of muscle activity and force fluctuations during steady voluntary contractions with multiple agonist muscles in humans. During a sustained low-farce contraction with the knee extensor Muscles, fluctuations in knee extension force changed concurrently with the involuntary alternate muscle activity between the rectus femoris muscle and the vasti muscles. After prolonged bed rest, the amount of change in the fluctuations in net force was associated with the amount of change in the EMG distribution among individual muscles within the knee extensor group and the ankle extensor group. As an adaptation to bed rest, an increase in the fluctuations in plantarflexion force accompanied an increase in the relative contribution of the medial gastrocnemius muscle to net force. In contrast, an increased contribution of the medial gastrocnemius by air acute increase in Muscle length reduced force fluctuations. The discrepancy in the changes in force fluctuations due to an increased contribution of the medial gastrocnemius between two interventions (bed rest and muscle length change) is associated with increased low-frequency power in the EMG of the medial gastrocnemius after bed rest. In summary, tire fluctuations in net force were influenced by the alteration in muscle activity among agonist muscles in terms of relative contributions to net force and frequency characteristics.
Laser-detected lateral muscle displacement is correlated with force fluctuations during voluntary contractions in humans JOURNAL OF NEUROSCIENCE METHODS,173(2):271-278 2008(Aug.) Author:Yasuhide Yoshitake; Kei Masani; Minoru Shinohara Abstract:Fluctuations in muscle force during steady voluntary contractions result from the summation of twitch forces produced by asynchronous activation of multiple motor units. We hypothesized that oscillatory lateral muscle displacement, measured with a non-contact high-resolution laser displacement sensor, is correlated with force fluctuations during steady, voluntary contractions with a human muscle. Eight healthy young adults (20-33 yrs) performed steady isometric contractions with the first dorsal interosseus muscle. Contraction intensity ranged from 2.5% to 60% of the maximal voluntary contraction force. Oscillatory lateral displacement of the muscle surface was measured with a high-resolution laser displacement sensor (0.5 mu m resolution), concurrently with abduction force of the index finger. In the time-domain analysis, there was a significant positive peak in the cross-correlation function between lateral muscle displacement and force fluctuations. In addition, the amplitude increased linearly with contraction intensity in both signals. In the frequency-domain analysis, frequency content was similar in both signals, and there was significant coherence between signals for the major frequency range of the signals (< 5 Hz). in conclusion, laser-detected lateral displacement of a hand muscle is correlated with force fluctuations across a wide range of contraction intensity during steady voluntary contractions in humans. (c) 2008 Elsevier B.V. All rights reserved.
Modulation of muscle activity and force fluctuations in the plantarflexors after bedrest depends on knee position MUSCLE & NERVE,35(6):745-755 2007(Jun.) Author:Yasuhide Yoshitake; Motoki Kouzaki; Hideoki Fukuoka; Tetsuo Fukunaga; Minoru Shinohara Abstract:Force fluctuations in leg muscles increase after bedrest, perhaps due to modulation of the neural strategy that is specific to a muscle or common to agonist muscles. The purpose of this study was to examine the modulation of muscle activity and force fluctuations during steady contractions with variable involvement of plantarflexor muscles after bedrest at knee-flexed (FLX) and extended (EXT) positions. Before and after 20-day bedrest, plantarflexion force and surface electromyogram (EMG) in the medial gastrocnemius (MG), lateral gastrocnemius, and soleus muscles were measured during steady isometric contractions in five young men. In EXT, power <= 10 Hz in the rectified EMG of MG increased significantly after bedrest. This low-frequency modulation of muscle activity in MG accompanied a 29% increase in the standard deviation of force. There was no change in EMG in other muscles. In FLX, there was no adjustment in EMG or force fluctuations. These results suggest that low-frequency modulation of MG plays a role in increasing force fluctuations during steady plantarflexion in EXT after bedrest. The findings indicate task/muscle specificity in the modulation of neural strategy during steady contractions after bedrest and underscore the importance of designing a specific training regimen targeted to particular tasks/muscles with regard to force fluctuations in multiple-agonist systems.
The medial gastrocnemius muscle attenuates force fluctuations during plantar flexion EXPERIMENTAL BRAIN RESEARCH,169(1):15-23 2006(Feb.) Author:M Shinohara; Y Yoshitake; M Kouzaki; T Fukunaga Abstract:Force fluctuations during steady contractions of multiple agonist muscles may be influenced by the relative contribution of force by each muscle. The purpose of the study was to compare force fluctuations during steady contractions performed with the plantar flexor muscles in different knee positions. Nine men (25.8 +/- 5.1 years) performed steady contractions of the plantar flexor muscles in the knee-flexed and knee-extended (greater involvement of the gastrocnemii muscles) positions. The maximal voluntary contraction (MVC) force was 32% greater in the knee-extended position compared with the knee-flexed position. The target forces were 2.5-10% MVC force in the respective position. The amplitude of electromyogram in the medial gastrocnemius muscle was greater in the knee-extended position (10.50 +/- 9.80%) compared with the knee-flexed position (1.26 +/- 1.15%, P < 0.01). The amplitude of electromyogram in the soleus muscle was not influenced by the knee position. The amplitude of electromyogram in the lateral gastrocnemius and tibialis anterior muscles was marginal and unaltered with knee position. At the same force (in Newtons), the standard deviation of force was lower in the knee-extended position compared with the knee-flexed position. These results indicate that force fluctuations during plantar flexion are attenuated with greater involvement of the medial gastrocnemius muscle.
Surface Mechanomyogram reflects the length changes in the fascicles of human skeletal muscles. International Journal of Sport and Health Science.,3(2005):280-285 2005 Author:Yoshitake Y; Kawakami Y; Kanehisa H; Fukunaga T Abstract:To examine the origin of mechanomyogram (MMG), we compared the responses of surface MMG with the changes in the fascicle length determined by ultrasonography during electrically induced contractions of human skeletal muscles. The posterior tibial nerve of subjects (n=5) was stimulated with a stimulus pattern in which the frequency rose up from 1Hz to 20Hz linearly. The MMG amplitude decreased with increasing stimulation frequency. Reduction of MMG amplitude was in parallel with the decrease in fluctuation of the changes in fascicle length, and these values had a significant positive correlation (r=0.94, P<0.001). The observed direct relation between MMG and architectural change of muscle indicates that surface MMG is generated by the pressure wave produced by the expansion of a number of muscle fibers during contractions.
Fluctuations in plantar flexion force are reduced after prolonged tendon vibration JOURNAL OF APPLIED PHYSIOLOGY,97(6):2090-2097 2004(Dec.) Author:Y Yoshitake; M Shinohara; M Kouzaki; T Fukunaga Abstract:The purpose of the study was to examine the effect of prolonged vibration on the force fluctuations during a force-matching task performed at low-force levels. Fourteen young healthy men performed a submaximal force-matching task of isometric plantar flexion before and after Achilles tendon vibration (n = 8, vibration subjects) or lying without vibration (n = 6, control subjects) for 30 min. The target forces were 2.5-10% of the previbration maximal voluntary contraction force. The standard deviation of force decreased by a mean of 29 +/- 20% across target forces after vibration, whereas it did not decrease significantly in control subjects (-5 +/- 12%). This change was significantly greater compared with control subjects (P < 0.01 for both). Power spectral density of the force was predominantly composed of signals of low-frequency bandwidth (&LE;5 Hz) with few higher frequency components. In vibration subjects, there was a significant decrease in power in the frequency range &LE;2 Hz after vibration. The decrease in power at this frequency range was linearly related to the decrease in the force fluctuations (r = 0.96, P < 0.001). The results indicate that prolonged Achilles tendon vibration reduces the fluctuations in plantar flexion force in the frequency range less than or equal to2 Hz during low-level contractions. It suggests that Ia afferent inputs contribute to the low-frequency force fluctuations in plantar flexion.
Strength training counteracts motor performance losses during bed rest. Journal of Applied Physiology,95(4):1485-1492 2003 Author:Shinohara M; Yoshitake Y; Kouzaki M; Fukuoka H; Fukunaga T
Characteristics of surface mechanomyogram are dependent on development of fusion of motor units in humans. Journal of Applied Physiology,93(5):1744-1752 2002 Author:Yoshitake Y; Shinohara M; Ue H; Moritani T
Assessment of lower-back muscle fatigue using electromyography, mechanomyography, and near-infrared spectroscopy European Journal of Applied Physiology,84(3):174-179 2001 Author:Y. Yoshitake; H. Ue; M. Miyazaki; T. Moritani Abstract:We have investigated the etiology of lowerback muscle fatigue using simultaneous recordings of electromyography (EMG), mechanomyography (MMG), and near-infrared spectroscopy (NIRS) in an attempt to shed some light on the electrophysiological, mechanical, and metabolic characteristics, respectively. Eight male subjects performed isometric back extensions at an angle of 15° with reference to the horizontal plane, for a period of 60 s. Surface EMG, MMG and NIRS signals were recorded simultaneously from the center of the erector spinae at the level of L3. NIRS was measured to determine the level of muscle blood volume (BV) and oxygenation (Oxy-Hb). The root mean square amplitude value (RMS) of the EMG signal was significantly increased at the initial phase of contraction and then fell significantly, while mean power frequency (MPF) of the EMG signal decreased significantly and progressively as a function of time. There were also significant initial increases in RMS-MMG that were followed by progressive decreases at the end of fatiguing contractions. MPF-MMG remained unchanged. Muscle BV and Oxy-Hb decreased dramatically at the onset of the contraction and then remained almost constant throughout the rest of the contraction. These results, obtained by simultaneous recordings of EMG, MMG, and NIRS, demonstrate that the restriction of blood flow due to high intramuscular mechanical pressure is one of the most important factors in muscle fatigue in the lower-back muscles. In addition, the simultaneous recording system described here can be used to obtain more reliable information regarding the mechanism(s) of lower-back muscle fatigue.
The muscle sound properties of different muscle fiber types during voluntary and electrically induced contractions Journal of Electromyography and Kinesiology,9(3):209-217 1999(Apr.) Author:Yasuhide Yoshitake; Toshio Moritani Abstract:Soundmyogram (SMG) and electromyogram signals were recorded simultaneously from the relatively fast medial gastrocnemius (MG) and slow soleus (SOL) during voluntary and electrically induced contractions. Using a spike-triggered averaging technique, the averaged elementary sound and corresponding MU spikes were also obtained from about 35 different MUs identified. The rms-SMG of MG increased as a function of force (P<
0.01). On the contrary, these values for SOL increased up to 60% MVC (P<
0.01), but decreased at 80% MVC. The relationship between the peak to peak amplitude of SMG and MU spike indicated significant positive correlations (r=0.631~0.657, P<
0.01). During electrical stimulation at 5 Hz, the SMG power spectral peak frequency (PF) was matched with stimulation frequency in both muscles. At higher stimulation frequencies, e.g., >
15 Hz, only in the MG was SMG-PF synchronized with stimulation frequency
the slow SOL did not show such synchronization. Our data suggest that the SMG frequency components might reflect active motor unit firing rates, and that the SMG amplitude depends upon mechanical properties of contraction, muscle fiber composition, and firing rate during voluntary and electrically induced contractions. Copyright (C) 1999 Elsevier Science Ltd.
The use of electromyography in applied physiology. J Electromyogr Kinesiol.,8:363-381 1998 Author:Moritani T; Yoshitake Y
MISC Relation Between Inspiratory Muscle Strength and Recruitment Onset of Neck Inspiratory Muscles MEDICINE AND SCIENCE IN SPORTS AND EXERCISE,49(5):798-798 2017(May) Author:Sohei Washino; Hironori Watanabe; Hiroaki Kanehisa; Yasuhide Yoshitake
Motor Execution And Imagery With Greater Task Difficulty Increases Corticospinal Excitability MEDICINE AND SCIENCE IN SPORTS AND EXERCISE,49(5):1033-1034 2017(May) Author:Hironori Watanabe; Sohei Washino; Hiroaki Kanehisa; Yasuhide Yoshitake
Effect of Body Mass-Based Squat Training on Knee Extensor Strength in Frail Elderly MEDICINE AND SCIENCE IN SPORTS AND EXERCISE,44:903-903 2012(May) Author:Eiji Fujita; Yasuhide Yoshitake; Yohei Takai; Hiroaki Kanehisa
Effects Of Resistance Training With Maximal Voluntary Co-contraction On Neuromuscular Function MEDICINE AND SCIENCE IN SPORTS AND EXERCISE,44:457-457 2012(May) Author:Sumiaki Maeo; Yasuhide Yoshitake; Yohei Takai; Tetsuo Fukunaga; Hiroaki Kanehisa
Muscle Deoxygenation and Myoelectric Activity During Sustained and Intermittent Isometric Exercise in Hypoxia MEDICINE AND SCIENCE IN SPORTS AND EXERCISE,42(5):466-466 2010(May) Author:Keisho Katayama; Yasuhide Yoshitake; Kohei Watanabe; Hiroshi Akima; Koji Ishida
Small Lateral Displacement of the Muscle Represents Low-Frequency Force Fluctuations During Voluntary Contractions in Humans MEDICINE AND SCIENCE IN SPORTS AND EXERCISE,38(5):S450-S450 2006(May) Author:Yasuhide Yoshitake; Minoru Shinohara
Low-frequency modulation of muscle activity in the medial gastrocnemius muscle after bed rest during steady plantar flexion in the knee-extended position. The 35th Annual Meeting Society for Neuroscience 2005 Author:Yoshitake Y; Shinohara M; Kouzaki M; Fukunaga T
Activation of gastrocnemii influences steadiness in plantarflexion force MEDICINE AND SCIENCE IN SPORTS AND EXERCISE,36(5):S6-S6 2004(May) Author:Y Yoshitake; M Shinohara; M Kouzaki; T Fukunaga
筋音図法を用いた力調節機能(steadiness)評価システムの開発 (第23回〔石本記念デサントスポーツ科学振興財団〕助成研究報告) デサントスポ-ツ科学,23:70-77 2002 Author:吉武 康栄; 篠原 稔; Enoka Roger M.
Behaviours of muscle-tendon complex during electrical stimulation with trains of linearly varying frequency in humans. 4th World Congress of Biomechanics 2002 Author:Yoshitake Y; Kawakami Y; Kanehisa H; Fukunaga T
220 Strength training during bed rest attenuates the decline in steadiness : Advances in exercise and sports physiology,7(4):179-179 2001 Author:YOSHITAKE Yasuhide; SHINOHARA Minoru; KOUZAKI Motoki; FUKUNAGA Tetsuo
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