The Experts below are selected from a list of 6366 Experts worldwide ranked by ideXlab platform

Gretchen D Oliver - One of the best experts on this subject based on the ideXlab platform.

  • relationship of glove arm kinematics with established Pitching kinematic and kinetic variables among youth baseball pitchers
    Orthopaedic Journal of Sports Medicine, 2018
    Co-Authors: Jeff W Barfield, Adam W Anz, James R Andrews, Gretchen D Oliver
    Abstract:

    Background:While the kinematics of the Pitching arm, trunk, and pelvis have been described and studied, glove arm kinematics remain an understudied portion of the Pitching Motion. Baseball pitchers...

  • gluteus medius and scapula muscle activations in youth baseball pitchers
    Journal of Strength and Conditioning Research, 2015
    Co-Authors: Gretchen D Oliver, Wendi H Weimar, Hillary A Plummer
    Abstract:

    The baseball Pitching Motion is a total kinetic chain activity that must efficiently use both the upper and lower extremity. Of particular importance is the scapular Motion, which is critical for humeral positioning and proper alignment of shoulder musculature. It was hypothesized that scapular stability is enhanced by pelvic girdle stability. Therefore, it was the purpose of this study to determine the muscle activations of selected pelvic and scapular stabilizing muscles during a fastball pitch in youth baseball pitchers. Twenty youth baseball pitchers (age: 11.3 + 1.0 years; height: 152.4 + 9.0 cm; weight: 47.5 + 11.3 kg) were recorded throwing 4-seam fastballs for strikes. Data revealed moderate (20–39% maximum voluntary isometric contraction [MVIC]) to moderately strong (>40% MVIC) activation of the ipsilateral (throwing arm side) gluteus medius, upper trapezius, and serratus anterior throughout phases 2 (maximum shoulder external rotation to ball release) and 3 (ball release to maximum shoulder internal rotation). Moderately strong activation (>40% MVIC) of the upper trapezius and serratus anterior was noted during phases 2 and 3 of the Pitching Motion. Pearson's product-moment correlation revealed significant relationships between bilateral gluteus medius and the force couples about the scapula during all 3 phases of the Pitching Motion. The results of this study provide important data that improve the understanding of the muscular relationship between the pelvic and scapular stabilizers during the fastball pitch. Training and rehabilitation programs should consider focusing on lumbopelvic-hip and scapular muscle strengthening as well as coordinated strengthening of the pelvic and scapular stabilizers, in baseball pitchers.

  • pelvis and torso kinematics and their relationship to shoulder kinematics in high school baseball pitchers
    Journal of Strength and Conditioning Research, 2010
    Co-Authors: Gretchen D Oliver, David W Keeley
    Abstract:

    It was the purpose of our study to examine the kinematics of the pelvis and torso and determine their relationship to the kinematics of the shoulder in high-school baseball pitchers. A single group, repeated-measures design was used to collect pelvis, torso, and shoulder kinematics throughout the Pitching Motion. Subjects threw a series of maximal effort fastballs to a catcher located the regulation distance (18.44m) from the Pitching mound, and those data from the fastest pitch passing through the strike zone were analyzed. After test trials, kinematic data were analyzed using a series of descriptive statistics to identify outliers and determine the nature of the distribution before testing for the presence of relationships between the various parameters. Results indicated that for several parameters, the actions at and about the shoulder are strongly related to the actions of the pelvis and torso throughout the Pitching Motion. However, although pelvis and torso kinematics throughout the Pitching Motion were inversely related to both shoulder elevation and the plane of shoulder elevation, only the rate of axial torso rotation was significantly related to these shoulder parameters. More importantly, the rate of axial torso rotation is significantly related to these shoulder parameters in a way that may help explain the high rate of shoulder injury in high-school pitchers. Therefore, strength training should focus on developing a strong stable core including the gluteal musculature in an attempt to control the rate of torso rotation during the pitch.

  • gluteal muscle group activation and its relationship with pelvis and torso kinematics in high school baseball pitchers
    Journal of Strength and Conditioning Research, 2010
    Co-Authors: Gretchen D Oliver, David W Keeley
    Abstract:

    The purpose of this study was to examine the activation patterns of the gluteal muscle group and their relationship to pelvis and torso kinematics throughout the high-school Pitching Motion. A single group, repeated-measures design was used to collect gluteus maximus and gluteus medius muscle activity through surface electromyography for the preferred and nonpreferred sides during the various phases of the Pitching Motion. In addition, data describing the kinematics of the pelvis and torso were collected at foot contact, maximum shoulder external rotation, ball release, and maximum shoulder internal rotation. For all pitchers, preferred gluteus maximus activity was observed to be in excess of 100% of their maximum voluntary isometric contraction throughout the stride and arm-cocking phases of the Pitching Motion. The observed means for the preferred gluteus medius, nonpreferred gluteus maximus, and nonpreferred gluteus medius, although different in magnitude, were similar in pattern. From the conclusion of the stride phase, through the conclusion of the arm-cocking phase, muscle activity increased for all pitchers. In examining the relationship between the rate of axial pelvis rotation and gluteal activity, several significant relationships were observed. In contrast, no significant relationships were observed with gluteal activity parameters and the rate of axial torso rotation. However, because the Pitching Motion progresses sequentially from the pelvis to the torso, variability in pelvis rotation may be directly related to variability in torso rotation. The findings from this study indicate that during the baseball pitch, there is a need for greater control of gluteal activation throughout the Pitching Motion.

David W Keeley - One of the best experts on this subject based on the ideXlab platform.

  • pelvis and torso kinematics and their relationship to shoulder kinematics in high school baseball pitchers
    Journal of Strength and Conditioning Research, 2010
    Co-Authors: Gretchen D Oliver, David W Keeley
    Abstract:

    It was the purpose of our study to examine the kinematics of the pelvis and torso and determine their relationship to the kinematics of the shoulder in high-school baseball pitchers. A single group, repeated-measures design was used to collect pelvis, torso, and shoulder kinematics throughout the Pitching Motion. Subjects threw a series of maximal effort fastballs to a catcher located the regulation distance (18.44m) from the Pitching mound, and those data from the fastest pitch passing through the strike zone were analyzed. After test trials, kinematic data were analyzed using a series of descriptive statistics to identify outliers and determine the nature of the distribution before testing for the presence of relationships between the various parameters. Results indicated that for several parameters, the actions at and about the shoulder are strongly related to the actions of the pelvis and torso throughout the Pitching Motion. However, although pelvis and torso kinematics throughout the Pitching Motion were inversely related to both shoulder elevation and the plane of shoulder elevation, only the rate of axial torso rotation was significantly related to these shoulder parameters. More importantly, the rate of axial torso rotation is significantly related to these shoulder parameters in a way that may help explain the high rate of shoulder injury in high-school pitchers. Therefore, strength training should focus on developing a strong stable core including the gluteal musculature in an attempt to control the rate of torso rotation during the pitch.

  • gluteal muscle group activation and its relationship with pelvis and torso kinematics in high school baseball pitchers
    Journal of Strength and Conditioning Research, 2010
    Co-Authors: Gretchen D Oliver, David W Keeley
    Abstract:

    The purpose of this study was to examine the activation patterns of the gluteal muscle group and their relationship to pelvis and torso kinematics throughout the high-school Pitching Motion. A single group, repeated-measures design was used to collect gluteus maximus and gluteus medius muscle activity through surface electromyography for the preferred and nonpreferred sides during the various phases of the Pitching Motion. In addition, data describing the kinematics of the pelvis and torso were collected at foot contact, maximum shoulder external rotation, ball release, and maximum shoulder internal rotation. For all pitchers, preferred gluteus maximus activity was observed to be in excess of 100% of their maximum voluntary isometric contraction throughout the stride and arm-cocking phases of the Pitching Motion. The observed means for the preferred gluteus medius, nonpreferred gluteus maximus, and nonpreferred gluteus medius, although different in magnitude, were similar in pattern. From the conclusion of the stride phase, through the conclusion of the arm-cocking phase, muscle activity increased for all pitchers. In examining the relationship between the rate of axial pelvis rotation and gluteal activity, several significant relationships were observed. In contrast, no significant relationships were observed with gluteal activity parameters and the rate of axial torso rotation. However, because the Pitching Motion progresses sequentially from the pelvis to the torso, variability in pelvis rotation may be directly related to variability in torso rotation. The findings from this study indicate that during the baseball pitch, there is a need for greater control of gluteal activation throughout the Pitching Motion.

Makoto Yokoyama - One of the best experts on this subject based on the ideXlab platform.

  • Pitching Motion control of a wheeled mobile robot with variable pitch blades via backstepping method
    Asian Control Conference, 2019
    Co-Authors: Makoto Yokoyama, Akihiko Kakuta
    Abstract:

    This paper presents a control strategy for a wheeled mobile robot with variable-pitch blades which make it highly mobile over irregular terrain. In our previous work, a mathematical model with respect to Pitching Motion of the robot necessary to climb a stair was developed, and a servo controller for the Pitching Motion was proposed under the assumption that the desired lift or down force was available as a control input. In this paper, taking the actuator dynamics into account, the controller is redesigned by applying the backstepping method to guarantee the asymptotic stability constructing a Lyapunov function, and its effectiveness is shown by numerical simulation.

  • ASCC - Pitching Motion Control of a Wheeled Mobile Robot with Variable-Pitch Blades via Backstepping Method
    2019
    Co-Authors: Makoto Yokoyama, Akihiko Kakuta
    Abstract:

    This paper presents a control strategy for a wheeled mobile robot with variable-pitch blades which make it highly mobile over irregular terrain. In our previous work, a mathematical model with respect to Pitching Motion of the robot necessary to climb a stair was developed, and a servo controller for the Pitching Motion was proposed under the assumption that the desired lift or down force was available as a control input. In this paper, taking the actuator dynamics into account, the controller is redesigned by applying the backstepping method to guarantee the asymptotic stability constructing a Lyapunov function, and its effectiveness is shown by numerical simulation.

  • Pitching Motion control of a wheeled mobile robot via full state linearization and extremum seeking
    Asian Control Conference, 2017
    Co-Authors: Makoto Yokoyama, Kazuya Sugihara
    Abstract:

    This paper presents a control strategy for a wheeled mobile robot with variable pitch blades which make it highly move over irregular terrain. A nonlinear controller for the Pitching Motion to climb a stair is proposed, employing full-state linearization technique together with integral sliding mode control to provide robust performance against model uncertainties such as ground adhesion properties. Furthermore, an extremum seeking technique is used to obtain the reference slip for high friction force between the tires and ground.

  • ASCC - Pitching Motion control of a wheeled mobile robot via full-state linearization and extremum seeking
    2017 11th Asian Control Conference (ASCC), 2017
    Co-Authors: Makoto Yokoyama, Kazuya Sugihara
    Abstract:

    This paper presents a control strategy for a wheeled mobile robot with variable pitch blades which make it highly move over irregular terrain. A nonlinear controller for the Pitching Motion to climb a stair is proposed, employing full-state linearization technique together with integral sliding mode control to provide robust performance against model uncertainties such as ground adhesion properties. Furthermore, an extremum seeking technique is used to obtain the reference slip for high friction force between the tires and ground.

  • modeling and control of Pitching Motion of a wheeled mobile robot with variable pitch blades
    IEEE SICE International Symposium on System Integration, 2015
    Co-Authors: Makoto Yokoyama, Masanori Isawa, Kazuya Takahashi
    Abstract:

    This paper presents a control strategy for a wheeled mobile robot with variable pitch blades which make it highly mobile over irregular terrain. A mathematical model with respect to Pitching Motion of the robot necessary to climb a stair is developed, and then a nonlinear controller for the Pitching Motion is proposed, employing input-output linearization technique together with integral sliding mode control to provide robust performance against model uncertainties such as ground adhesion properties.

Hillary A Plummer - One of the best experts on this subject based on the ideXlab platform.

  • gluteus medius and scapula muscle activations in youth baseball pitchers
    Journal of Strength and Conditioning Research, 2015
    Co-Authors: Gretchen D Oliver, Wendi H Weimar, Hillary A Plummer
    Abstract:

    The baseball Pitching Motion is a total kinetic chain activity that must efficiently use both the upper and lower extremity. Of particular importance is the scapular Motion, which is critical for humeral positioning and proper alignment of shoulder musculature. It was hypothesized that scapular stability is enhanced by pelvic girdle stability. Therefore, it was the purpose of this study to determine the muscle activations of selected pelvic and scapular stabilizing muscles during a fastball pitch in youth baseball pitchers. Twenty youth baseball pitchers (age: 11.3 + 1.0 years; height: 152.4 + 9.0 cm; weight: 47.5 + 11.3 kg) were recorded throwing 4-seam fastballs for strikes. Data revealed moderate (20–39% maximum voluntary isometric contraction [MVIC]) to moderately strong (>40% MVIC) activation of the ipsilateral (throwing arm side) gluteus medius, upper trapezius, and serratus anterior throughout phases 2 (maximum shoulder external rotation to ball release) and 3 (ball release to maximum shoulder internal rotation). Moderately strong activation (>40% MVIC) of the upper trapezius and serratus anterior was noted during phases 2 and 3 of the Pitching Motion. Pearson's product-moment correlation revealed significant relationships between bilateral gluteus medius and the force couples about the scapula during all 3 phases of the Pitching Motion. The results of this study provide important data that improve the understanding of the muscular relationship between the pelvic and scapular stabilizers during the fastball pitch. Training and rehabilitation programs should consider focusing on lumbopelvic-hip and scapular muscle strengthening as well as coordinated strengthening of the pelvic and scapular stabilizers, in baseball pitchers.

S. D. Xue - One of the best experts on this subject based on the ideXlab platform.

  • Tuned liquid column damper for suppressing Pitching Motion of structures
    Engineering Structures, 2000
    Co-Authors: S. D. Xue
    Abstract:

    Abstract Tuned liquid column damper (TLCD) was developed mainly for the purpose of suppressing horizontal Motion of structures. No relevant research has been found on the suppression of structural Pitching vibration by using TLCD. This paper thus aims to investigate the possibility and effectiveness of applying TLCD to suppress Pitching Motion of structures. Both theoretical and experimental investigations are carried out. A mathematical model of tuned liquid column damper for suppressing structural Pitching vibration is developed. The TLCD-structure interactive equations are derived and solved in both time domain and frequency domain. A series of free and forced vibration experiments with different TLCD configuration and parameters are performed. The influences of variable TLCD parameters on control effectiveness are determined. Numerical simulations corresponding to the experimental cases are carried out and compared with the experiments. A close agreement is obtained between the experimental results and theoretical simulation. This also verifies the developed theoretical model. Both theoretical and experimental studies show that TLCD can efficiently reduce structural Pitching Motion.

  • Experimental investigation of structural Pitching Motion control by a tuned-liquid column damper
    Smart Structures and Materials 1998: Passive Damping and Isolation, 1998
    Co-Authors: S. D. Xue
    Abstract:

    Tuned liquid column damper (TLCD) was developed mainly for the purpose of suppressing horizontal Motion of structures. No relevant research has been found on the suppression of structural Pitching vibration by using TLCD. This paper thus conducts a series of TLCD experiments with different configurations and parameters to investigate the possibility and effectiveness of applying TLCD to reduce Pitching Motion of structures. A theoretical model of TLCD-structure interaction under Pitching Motion is also developed to guide the experiments and verified by the experimental results on the other hand. In this study, the influence of variable TLCD parameters on control effectiveness are determined. It is concluded that TLCD can efficiently reduce structural Pitching Motion.