Rafael Escamilla - Profile on Academia.edu (original) (raw)
Papers by Rafael Escamilla
A Comparison Of Four Practical And Reliable Methods Of Assessing Body Fat Among Young, Middle Age, And Older Healthy Adults
Medicine and Science in Sports and Exercise, Sep 1, 2022
Journal of Orthopaedic & Sports Physical Therapy, Mar 1, 2012
1. Title Page: What's New in ACL Rehabilitation? Evidence Based Approach for the Selection and Application of Strength and Neuromuscular Control Exercises
- Alan Hirahara, MD, FRCSC: Sacramento Orthopaedic Center, Sacramento, CA 2) Kevin Wilk, PT, DPT... more 1) Alan Hirahara, MD, FRCSC: Sacramento Orthopaedic Center, Sacramento, CA 2) Kevin Wilk, PT, DPT, FAPTA: Champion Sports Medicine, Birmingham, AL 3) Kyle Yamashiro, PT, CSCS: Results Physical Therapy and Training Center, Sacramento, CA 4) Rafael Escamilla, PT, PhD, CSCS, FACSM: Department of Physical Therapy, California State University, Sacramento, Sacramento, CA 5) Toran MacLeod, PT, PhD: Department of Physical Therapy, California State University, Sacramento, Sacramento, CA
This material is the copyright of the original publisher. Unauthorised copying and distribution is prohibited. Shoulder Muscle Activity and Function in Common Shoulder Rehabilitation Exercises
Effects of Contralateral Trunk Tilt on Shoulder and Elbow Injury Risk and Pitching Biomechanics in Professional Baseball Pitchers
The American Journal of Sports Medicine
Background: Baseball pitchers employ various contralateral trunk tilt (CTT) positions when pitchi... more Background: Baseball pitchers employ various contralateral trunk tilt (CTT) positions when pitching depending on if they have an overhand, three-quarter, or sidearm delivery. There are no known studies that have examined how pitching biomechanics are significantly different in professional pitchers with varying amounts of CTT, which may provide insight into shoulder and elbow injury risk among pitchers with different CTT. Purpose: To assess differences in shoulder and elbow forces and torques and baseball pitching biomechanics in professional pitchers with maximum 30° to 40° CTT (MaxCTT), moderate 15° to 25° CTT (ModCTT), and minimum 0° to 10° CTT (MinCTT). Study Design: Controlled laboratory study. Methods: In total, 215 pitchers were examined, including 46 pitchers with MaxCTT, 126 pitchers with ModCTT, and 43 pitchers with MinCTT. All pitchers were tested using a 240-Hz, 10-camera motion analysis system, and 37 kinematic and kinetic parameters were calculated. Differences in kine...
Advances in orthopedics, May 28, 2022
Purpose. e optimal surgical technique for unstable acromioclavicular (AC) and coracoclavicular (C... more Purpose. e optimal surgical technique for unstable acromioclavicular (AC) and coracoclavicular (CC) joint injuries has not yet been established. e biomechanical and radiographic e ect of the LockDown device, a synthetic ligament for AC joint reconstruction, was evaluated to assess the optimal surgical technique for unstable AC and CC joint injuries. It was hypothesized that the LockDown device would restore AC joint kinematics and radiographic stability to near native values. Methods. ree fresh frozen cadaveric torsos (6 shoulders) modelled CC joint motion in their "native," "severed," and "reconstructed" states. e e ects of stressed and unstressed native, severed, and reconstructed conditions on AC separation and CC distances in anteroposterior, mediolateral, and inferosuperior directions during shoulder abduction, exion, and scaption were assessed. e analysis of variance (p, 0.05) was used to compare CC distance and peak AC distance in anteroposterior, mediolateral, and inferosuperior directions during shoulder exion, abduction, and scaption measurements among native, severed, and reconstructed states with unstressed and stressed Zanca radiographic views. Results. From radiographic analyses, the CC distance was signi cantly greater (p 0.001) across the surgical state in stressed versus unstressed views. Mean di erence between stressed and unstressed views was 1.8 mm in native state, 4.1 mm in severed state, and 0.9 mm in reconstructed state. e CC distance was signi cantly greater in the "severed" state (10.4 mm unstressed; 14.5 mm stressed) compared to the "native" state (p 0.016) (6.5 mm unstressed; 8.3 mm stressed) and compared to the "reconstructed" state (p 0.005) (3.1 mm unstressed; 4.0 mm stressed) and signi cantly less (p 0.008) in the "reconstructed" state compared to the "native" state. CC distances decreased from native to reconstructed, an average of 3.3 mm for unstressed and 4.3 mm for stressed. On average, peak AC joint separation distance in anteroposterior, mediolateral, and inferosuperior directions during shoulder-abduction, exion, and scaption was shown to be restored to 11.5 mm of native values after reconstruction with LockDown device. Conclusion. Reconstruction of AC joint with LockDown synthetic ligament restores motion of clavicle and acromion to near native values, thereby decreasing scapular dyskinesis and enhancing AC joint stability.
Chinese Journal of Orthopaedics, 2009
Background: A relatively high number of active professional baseball pitchers have a history of u... more Background: A relatively high number of active professional baseball pitchers have a history of ulnar collateral ligament reconstruction (UCLr) on their throwing elbow. Controversy exists in the literature about whether professional baseball pitchers regain optimal performance after return from UCLr. It has been suggested that pitchers may have different biomechanics after UCLr, but this has not been previously tested. Hypothesis: It was hypothesized that, compared with a control group without a history of UCLr, professional pitchers with a history of UCLr would have (1) significantly different throwing elbow and shoulder biomechanics; (2) a shortened stride, insufficient trunk forward tilt, and excessive shoulder horizontal adduction, characteristics associated with ''holding back'' or being tentative; (3) late shoulder rotation; and (4) improper shoulder abduction and trunk lateral tilt.
Chinese Journal of Orthopaedics, 2009
背景:在髌股关节康复训练中经常进行负重的弓步动作,但这种动作下的髌股关节压力和应力状况尚不明确.方法 :18名受试者在负重下做跨步和不跨步的前弓步和侧弓步动作,负重承量为口J进行12次重复动作的... more 背景:在髌股关节康复训练中经常进行负重的弓步动作,但这种动作下的髌股关节压力和应力状况尚不明确.方法 :18名受试者在负重下做跨步和不跨步的前弓步和侧弓步动作,负重承量为口J进行12次重复动作的最大负荷.将肌电学、测力平台以及运动学数据输入生物力学模型中,计算不同膝关节屈曲角度下的髌股关节压力和应力.结果 :髌股关节的压力和应力随膝关节屈曲角度增加而增高,随膝关节屈曲角度减小而降低.膝关节屈曲80°～90°时,侧弓步下的髌股关节压力和应力大于前弓步;膝关节屈曲10°～50°时,跨步下的髌股关节压力和应力大于不跨步.弓步和跨步之间无明显的相互作用.膝关节屈曲0°～50°时髌股关节压力和应力小于膝关节屈曲60°～90°时的压力和应力,因此在髌股关节康复训练早期应限制膝关节屈曲在50°以内.解释:为了尽量减小髌股关节的压力和应力,应当在不跨步下进行前弓步和侧弓步练习,尤其是膝关节屈曲0°～50°时.了解不同弓步间髌股关节压力和应力的差异,可能有助于临床医生制定更加安全有效的康复训练方法。
Patellofemoral Joint Loading In Forward Lunge Rehabilitation Exercises
Medicine & Science in Sports & Exercise, 2021
Journal of Applied Biomechanics, 1998
Previous researchers studying baseball pitching have compared kinematic and kinetic parameters am... more Previous researchers studying baseball pitching have compared kinematic and kinetic parameters among different types of pitches, focusing on the trunk, shoulder, and elbow. The lack of data on the wrist and forearm limits the understanding of clinicians, coaches, and researchers regarding the mechanics of baseball pitching and the differences among types of pitches. The purpose of this study was to expand existing knowledge of baseball pitching by quantifying and comparing kinematic data of the wrist and forearm for the fastball (FA), curveball (CU) and change-up (CH) pitches. Kinematic and temporal parameters were determined from 8 collegiate pitchers recorded with a four-camera system (200 Hz). Although significant differences were observed for all pitch comparisons, the least number of differences occurred between the FA and CH. During arm cocking, peak wrist extension for the FA and CH pitches was greater than for the CU, while forearm supination was greater for the CU. In contr...
Kinematic Comparisons of Throwing Different Types of Baseball Pitches
Journal of Applied Biomechanics, 1998
The purpose of this study was to establish and compare kinematic data among four groups of colleg... more The purpose of this study was to establish and compare kinematic data among four groups of collegiate pitchers who threw the fastball (FA), change-up (CH), curveball (CU), and slider (SL). Twenty-six kinematic parameters at lead foot contact, during the arm-cocking and arm acceleration phases, and at ball release were measured for 16 collegiate baseball pitchers. Approximately 60% of these parameters showed significant differences among the four pitch variations. The greatest number of differences (14 of 26) occurred between the FA and CH groups, while the fewest differences (2 of 26) occurred between the FA and SL groups. The CH group had the smallest knee and elbow flexion at lead foot contact and the greatest knee and elbow flexion at ball release. During the arm-cocking and arm acceleration phases, peak shoulder, elbow, and trunk angular velocities were generally greatest in the FA and SL groups and smallest in the CH group. At ball release the CH group had the most upright trun...
Medicine & Science in Sports & Exercise, 2017
To compare peak patellofemoral and ACL/PCL forces among varying lunging techniques involving lung... more To compare peak patellofemoral and ACL/PCL forces among varying lunging techniques involving lunging with a long and short stride both on flat ground and up to a 4 inch platform. METHODS: Sixteen male and female subjects (mean bodyweight 678N, 69.1 kg mass; 175.9 cm height; 28.9 years old) using bodyweight only performed a forward lunge with a long stride (shank vertical at bottom position) and a short stride (1/2 the long stride distance) on flat ground and up to a 4 inch platform. Force platform and video data were collected and input into a biomechanical model, and peak patellofemoral and ACL/PCL were calculated as a function of knee angle. A One-Way Repeated measures ANOVA assessed significant differences among lunging techniques (p<0.05). RESULTS: Peak patellofemoral force occurred between 79°-96° knee angles and was significantly greater (p<0.001) with a short stride lunge on flat ground (1668±479N) and up to a 4 inch platform (1553±580N) compared to lunging with a long stride lunge on flat ground (1193±512N) and up to a 4 inch platform (1061±523N), but no significant differences in peak patellofemoral force were found between the two short stride lunges (p=0.99) and between the two long stride lunges (p=0.99). Peak ACL force occurred between 7°-12° knee angles and was not significantly different (p=0.70) among any of the lunging techniques. Peak PCL force occurred between 62°-83° knee angles and was significantly greater (p<0.001) with a long stride lunge on flat ground (554±220N) and up to a 4 inch platform (609±265N) compared to lunging with a long stride lunge on flat ground (402±114N) and up to a 4 inch platform (458±145N), but no significant differences in peak PCL force were found between the two short stride lunges (p=0.99) and between the two long stride lunges (p=.99). CONCLUSIONS: Lunge technique variations did affect peak patellofemoral and cruciate ligament forces. Compared to a long stride lunge, lunging with a short stride, which caused the knees to translate forward approximately 8 cm beyond the knees at bottom lunge position, resulted in greater peak patellofemoral force but less PCL force. Lunging technique variations did not affect peak ACL force. There were no patellofemoral or PCL differences in peak force between the two long stride lunges or between the two short stride lunges.
Patellofemoral Joint Loading During the Performance of the Wall Squat and Ball Squat with Heel-to-Wall-Distance Variations
Medicine & Science in Sports & Exercise
Patellofemoral Joint Loading in Forward Lunge With Step Length and Height Variations
Journal of Applied Biomechanics
The objective was to assess how patellofemoral loads (joint force and stress) change while lungin... more The objective was to assess how patellofemoral loads (joint force and stress) change while lunging with step length and step height variations. Sixteen participants performed a forward lunge using short and long steps at ground level and up to a 10-cm platform. Electromyography, ground reaction force, and 3D motion were captured, and patellofemoral loads were calculated as a function of knee angle. Repeated-measures 2-way analysis of variance (P < .05) was employed. Patellofemoral loads in the lead knee were greater with long step at the beginning of landing (10°–30° knee angle) and the end of pushoff (10°–40°) and greater with short step during the deep knee flexion portion of the lunge (50°–100°). Patellofemoral loads were greater at ground level than 10-cm platform during lunge descent (50°–100°) and lunge ascent (40°–70°). Patellofemoral loads generally increased as knee flexion increased and decreased as knee flexion decreased. To gradually increase patellofemoral loads, per...
International Journal of Sports Physical Therapy, 2022
Background Forward and side lunge exercises strengthen hip and thigh musculature, enhance patello... more Background Forward and side lunge exercises strengthen hip and thigh musculature, enhance patellofemoral joint stability, and are commonly used during patellofemoral rehabilitation and training for sport. Hypothesis/Purpose The purpose was to quantify, via calculated estimates, patellofemoral force and stress between two lunge type variations (forward lunge versus side lunge) and between two step height variations (ground level versus 10 cm platform). The hypotheses were that patellofemoral force and stress would be greater at all knee angles performing the bodyweight side lunge compared to the bodyweight forward lunge, and greater when performing the forward and side lunge at ground level compared to up a 10cm platform. Study Design Controlled laboratory biomechanics repeated measures, counterbalanced design. Methods Sixteen participants performed a forward and side lunge at ground level and up a 10cm platform. Electromyographic, ground reaction force, and kinematic variables were collected and input into a biomechanical optimization model, and patellofemoral joint force and stress were calculated as a function of knee angle during the lunge descent and ascent and assessed with a repeated measures 2-way ANOVA (p<0.05).
Journal of Orthopaedic & Sports Physical Therapy, 2010
Core Muscle Activation During Swiss Ball and Traditional Abdominal Exercises t he "core" has been... more Core Muscle Activation During Swiss Ball and Traditional Abdominal Exercises t he "core" has been used to refer to the lumbopelvic-hip complex, which involves deeper muscles, such as the internal oblique, transversus abdominis, transversospinalis (multifidus, rotatores, semispinalis), quadratus lumborum, and psoas major and minor, and superficial muscles, such as the rectus abdominis, external oblique, erector spinae (iliocostalis, spinalis, longissimus),
Kinematic and kinetic comparison betweein American and Korean professional baseball pitchers / Rafael Escamilla ...[et al.]
International Journal of Sports Physical Therapy, 2016
In spite of the bodyblade (BB®) being used in clinical settings during shoulder and trunk rehabil... more In spite of the bodyblade (BB®) being used in clinical settings during shoulder and trunk rehabilitation and training for 24 years, there are only five known scientific papers that have described muscle recruitment patterns using the BB®. Moreover, there are no known studies that have examined muscle activity differences between males and females (who both use the bodyblade in the clinic) or between different BB® devices. The primary purposes of this investigation were to compare glenohumeral and scapular muscle activity between the Bodyblade® Pro (BB®P) and Bodyblade® Classic (BB®C) devices while performing a variety of exercises, as well as to compare muscle activity between males and females. It was hypothesized that glenohumeral and scapular muscle activity would be significantly greater in females compared to males, significantly greater while performing exercises with the BB®P compared to the BB®C, significantly different among various BB® exercises, and greater with two hand ...
Journal of Sports Science and Medicine, Oct 1, 2007
The purpose of this study was to compare the kinematics of kuzushi/tsukuri (KT) phases of the har... more The purpose of this study was to compare the kinematics of kuzushi/tsukuri (KT) phases of the harai-goshi throw under competitive and non-competitive conditions. A third degree black belt subject served as the tori (thrower) for both conditions. Two black belt participants ranked as first degree and fourth degree served as the uke (faller) for the competitive and non-competitive conditions, respectively. Two video cameras (JVC 60 Hz) and a three dimensional motion analysis system (Vicon-Peak Performance Technologies, Inc., Englewood, CO) were used to collect and analyze peak velocity for the center of mass (COM) of uke and tori and peak angular velocity of tori's trunk (TAV). Data were smoothed using a 4(th) order zero lag Butterworth filter with a cut-off frequency set by the Peak software optimization technique. All variables were normalized by time as a percentage of the KT phase. In general, the COM directional velocity patterns were similar between conditions. Uke's def...
Journal of Sports Science and Medicine, Jul 1, 2006
Four black belt throwers (tori) and one black belt faller (uke) were filmed and analyzed in three... more Four black belt throwers (tori) and one black belt faller (uke) were filmed and analyzed in three-dimensions using two video cameras (JVC 60 Hz) and motion analysis software. Average linear momentum in the anteroposterior (x), vertical (y), and mediolateral (z) directions and average resultant impulse of uke's center of mass (COM) were investigated for three different throwing techniques; harai-goshi (hip throw), seoi-nage (hand throw), and osoto-gari (leg throw). Each throw was broken down into three main phases; kuzushi (balance breaking), tsukuri (fit-in), and kake (throw). For the harai-goshi and osoto-gari throws, impulse measurements were the largest within kuzushi and tsukuri phases (where collision between tori and uke predominantly occurs). Both throws indicated an importance for tori to create large momentum prior to contact with uke. The seoi-nage throw demonstrated the lowest impulse and maintained forward momentum on the body of uke throughout the entire throw. The ...
A Comparison Of Four Practical And Reliable Methods Of Assessing Body Fat Among Young, Middle Age, And Older Healthy Adults
Medicine and Science in Sports and Exercise, Sep 1, 2022
Journal of Orthopaedic & Sports Physical Therapy, Mar 1, 2012
1. Title Page: What's New in ACL Rehabilitation? Evidence Based Approach for the Selection and Application of Strength and Neuromuscular Control Exercises
- Alan Hirahara, MD, FRCSC: Sacramento Orthopaedic Center, Sacramento, CA 2) Kevin Wilk, PT, DPT... more 1) Alan Hirahara, MD, FRCSC: Sacramento Orthopaedic Center, Sacramento, CA 2) Kevin Wilk, PT, DPT, FAPTA: Champion Sports Medicine, Birmingham, AL 3) Kyle Yamashiro, PT, CSCS: Results Physical Therapy and Training Center, Sacramento, CA 4) Rafael Escamilla, PT, PhD, CSCS, FACSM: Department of Physical Therapy, California State University, Sacramento, Sacramento, CA 5) Toran MacLeod, PT, PhD: Department of Physical Therapy, California State University, Sacramento, Sacramento, CA
This material is the copyright of the original publisher. Unauthorised copying and distribution is prohibited. Shoulder Muscle Activity and Function in Common Shoulder Rehabilitation Exercises
Effects of Contralateral Trunk Tilt on Shoulder and Elbow Injury Risk and Pitching Biomechanics in Professional Baseball Pitchers
The American Journal of Sports Medicine
Background: Baseball pitchers employ various contralateral trunk tilt (CTT) positions when pitchi... more Background: Baseball pitchers employ various contralateral trunk tilt (CTT) positions when pitching depending on if they have an overhand, three-quarter, or sidearm delivery. There are no known studies that have examined how pitching biomechanics are significantly different in professional pitchers with varying amounts of CTT, which may provide insight into shoulder and elbow injury risk among pitchers with different CTT. Purpose: To assess differences in shoulder and elbow forces and torques and baseball pitching biomechanics in professional pitchers with maximum 30° to 40° CTT (MaxCTT), moderate 15° to 25° CTT (ModCTT), and minimum 0° to 10° CTT (MinCTT). Study Design: Controlled laboratory study. Methods: In total, 215 pitchers were examined, including 46 pitchers with MaxCTT, 126 pitchers with ModCTT, and 43 pitchers with MinCTT. All pitchers were tested using a 240-Hz, 10-camera motion analysis system, and 37 kinematic and kinetic parameters were calculated. Differences in kine...
Advances in orthopedics, May 28, 2022
Purpose. e optimal surgical technique for unstable acromioclavicular (AC) and coracoclavicular (C... more Purpose. e optimal surgical technique for unstable acromioclavicular (AC) and coracoclavicular (CC) joint injuries has not yet been established. e biomechanical and radiographic e ect of the LockDown device, a synthetic ligament for AC joint reconstruction, was evaluated to assess the optimal surgical technique for unstable AC and CC joint injuries. It was hypothesized that the LockDown device would restore AC joint kinematics and radiographic stability to near native values. Methods. ree fresh frozen cadaveric torsos (6 shoulders) modelled CC joint motion in their "native," "severed," and "reconstructed" states. e e ects of stressed and unstressed native, severed, and reconstructed conditions on AC separation and CC distances in anteroposterior, mediolateral, and inferosuperior directions during shoulder abduction, exion, and scaption were assessed. e analysis of variance (p, 0.05) was used to compare CC distance and peak AC distance in anteroposterior, mediolateral, and inferosuperior directions during shoulder exion, abduction, and scaption measurements among native, severed, and reconstructed states with unstressed and stressed Zanca radiographic views. Results. From radiographic analyses, the CC distance was signi cantly greater (p 0.001) across the surgical state in stressed versus unstressed views. Mean di erence between stressed and unstressed views was 1.8 mm in native state, 4.1 mm in severed state, and 0.9 mm in reconstructed state. e CC distance was signi cantly greater in the "severed" state (10.4 mm unstressed; 14.5 mm stressed) compared to the "native" state (p 0.016) (6.5 mm unstressed; 8.3 mm stressed) and compared to the "reconstructed" state (p 0.005) (3.1 mm unstressed; 4.0 mm stressed) and signi cantly less (p 0.008) in the "reconstructed" state compared to the "native" state. CC distances decreased from native to reconstructed, an average of 3.3 mm for unstressed and 4.3 mm for stressed. On average, peak AC joint separation distance in anteroposterior, mediolateral, and inferosuperior directions during shoulder-abduction, exion, and scaption was shown to be restored to 11.5 mm of native values after reconstruction with LockDown device. Conclusion. Reconstruction of AC joint with LockDown synthetic ligament restores motion of clavicle and acromion to near native values, thereby decreasing scapular dyskinesis and enhancing AC joint stability.
Chinese Journal of Orthopaedics, 2009
Background: A relatively high number of active professional baseball pitchers have a history of u... more Background: A relatively high number of active professional baseball pitchers have a history of ulnar collateral ligament reconstruction (UCLr) on their throwing elbow. Controversy exists in the literature about whether professional baseball pitchers regain optimal performance after return from UCLr. It has been suggested that pitchers may have different biomechanics after UCLr, but this has not been previously tested. Hypothesis: It was hypothesized that, compared with a control group without a history of UCLr, professional pitchers with a history of UCLr would have (1) significantly different throwing elbow and shoulder biomechanics; (2) a shortened stride, insufficient trunk forward tilt, and excessive shoulder horizontal adduction, characteristics associated with ''holding back'' or being tentative; (3) late shoulder rotation; and (4) improper shoulder abduction and trunk lateral tilt.
Chinese Journal of Orthopaedics, 2009
背景:在髌股关节康复训练中经常进行负重的弓步动作,但这种动作下的髌股关节压力和应力状况尚不明确.方法 :18名受试者在负重下做跨步和不跨步的前弓步和侧弓步动作,负重承量为口J进行12次重复动作的... more 背景:在髌股关节康复训练中经常进行负重的弓步动作,但这种动作下的髌股关节压力和应力状况尚不明确.方法 :18名受试者在负重下做跨步和不跨步的前弓步和侧弓步动作,负重承量为口J进行12次重复动作的最大负荷.将肌电学、测力平台以及运动学数据输入生物力学模型中,计算不同膝关节屈曲角度下的髌股关节压力和应力.结果 :髌股关节的压力和应力随膝关节屈曲角度增加而增高,随膝关节屈曲角度减小而降低.膝关节屈曲80°～90°时,侧弓步下的髌股关节压力和应力大于前弓步;膝关节屈曲10°～50°时,跨步下的髌股关节压力和应力大于不跨步.弓步和跨步之间无明显的相互作用.膝关节屈曲0°～50°时髌股关节压力和应力小于膝关节屈曲60°～90°时的压力和应力,因此在髌股关节康复训练早期应限制膝关节屈曲在50°以内.解释:为了尽量减小髌股关节的压力和应力,应当在不跨步下进行前弓步和侧弓步练习,尤其是膝关节屈曲0°～50°时.了解不同弓步间髌股关节压力和应力的差异,可能有助于临床医生制定更加安全有效的康复训练方法。
Patellofemoral Joint Loading In Forward Lunge Rehabilitation Exercises
Medicine & Science in Sports & Exercise, 2021
Journal of Applied Biomechanics, 1998
Previous researchers studying baseball pitching have compared kinematic and kinetic parameters am... more Previous researchers studying baseball pitching have compared kinematic and kinetic parameters among different types of pitches, focusing on the trunk, shoulder, and elbow. The lack of data on the wrist and forearm limits the understanding of clinicians, coaches, and researchers regarding the mechanics of baseball pitching and the differences among types of pitches. The purpose of this study was to expand existing knowledge of baseball pitching by quantifying and comparing kinematic data of the wrist and forearm for the fastball (FA), curveball (CU) and change-up (CH) pitches. Kinematic and temporal parameters were determined from 8 collegiate pitchers recorded with a four-camera system (200 Hz). Although significant differences were observed for all pitch comparisons, the least number of differences occurred between the FA and CH. During arm cocking, peak wrist extension for the FA and CH pitches was greater than for the CU, while forearm supination was greater for the CU. In contr...
Kinematic Comparisons of Throwing Different Types of Baseball Pitches
Journal of Applied Biomechanics, 1998
The purpose of this study was to establish and compare kinematic data among four groups of colleg... more The purpose of this study was to establish and compare kinematic data among four groups of collegiate pitchers who threw the fastball (FA), change-up (CH), curveball (CU), and slider (SL). Twenty-six kinematic parameters at lead foot contact, during the arm-cocking and arm acceleration phases, and at ball release were measured for 16 collegiate baseball pitchers. Approximately 60% of these parameters showed significant differences among the four pitch variations. The greatest number of differences (14 of 26) occurred between the FA and CH groups, while the fewest differences (2 of 26) occurred between the FA and SL groups. The CH group had the smallest knee and elbow flexion at lead foot contact and the greatest knee and elbow flexion at ball release. During the arm-cocking and arm acceleration phases, peak shoulder, elbow, and trunk angular velocities were generally greatest in the FA and SL groups and smallest in the CH group. At ball release the CH group had the most upright trun...
Medicine & Science in Sports & Exercise, 2017
To compare peak patellofemoral and ACL/PCL forces among varying lunging techniques involving lung... more To compare peak patellofemoral and ACL/PCL forces among varying lunging techniques involving lunging with a long and short stride both on flat ground and up to a 4 inch platform. METHODS: Sixteen male and female subjects (mean bodyweight 678N, 69.1 kg mass; 175.9 cm height; 28.9 years old) using bodyweight only performed a forward lunge with a long stride (shank vertical at bottom position) and a short stride (1/2 the long stride distance) on flat ground and up to a 4 inch platform. Force platform and video data were collected and input into a biomechanical model, and peak patellofemoral and ACL/PCL were calculated as a function of knee angle. A One-Way Repeated measures ANOVA assessed significant differences among lunging techniques (p<0.05). RESULTS: Peak patellofemoral force occurred between 79°-96° knee angles and was significantly greater (p<0.001) with a short stride lunge on flat ground (1668±479N) and up to a 4 inch platform (1553±580N) compared to lunging with a long stride lunge on flat ground (1193±512N) and up to a 4 inch platform (1061±523N), but no significant differences in peak patellofemoral force were found between the two short stride lunges (p=0.99) and between the two long stride lunges (p=0.99). Peak ACL force occurred between 7°-12° knee angles and was not significantly different (p=0.70) among any of the lunging techniques. Peak PCL force occurred between 62°-83° knee angles and was significantly greater (p<0.001) with a long stride lunge on flat ground (554±220N) and up to a 4 inch platform (609±265N) compared to lunging with a long stride lunge on flat ground (402±114N) and up to a 4 inch platform (458±145N), but no significant differences in peak PCL force were found between the two short stride lunges (p=0.99) and between the two long stride lunges (p=.99). CONCLUSIONS: Lunge technique variations did affect peak patellofemoral and cruciate ligament forces. Compared to a long stride lunge, lunging with a short stride, which caused the knees to translate forward approximately 8 cm beyond the knees at bottom lunge position, resulted in greater peak patellofemoral force but less PCL force. Lunging technique variations did not affect peak ACL force. There were no patellofemoral or PCL differences in peak force between the two long stride lunges or between the two short stride lunges.
Patellofemoral Joint Loading During the Performance of the Wall Squat and Ball Squat with Heel-to-Wall-Distance Variations
Medicine & Science in Sports & Exercise
Patellofemoral Joint Loading in Forward Lunge With Step Length and Height Variations
Journal of Applied Biomechanics
The objective was to assess how patellofemoral loads (joint force and stress) change while lungin... more The objective was to assess how patellofemoral loads (joint force and stress) change while lunging with step length and step height variations. Sixteen participants performed a forward lunge using short and long steps at ground level and up to a 10-cm platform. Electromyography, ground reaction force, and 3D motion were captured, and patellofemoral loads were calculated as a function of knee angle. Repeated-measures 2-way analysis of variance (P < .05) was employed. Patellofemoral loads in the lead knee were greater with long step at the beginning of landing (10°–30° knee angle) and the end of pushoff (10°–40°) and greater with short step during the deep knee flexion portion of the lunge (50°–100°). Patellofemoral loads were greater at ground level than 10-cm platform during lunge descent (50°–100°) and lunge ascent (40°–70°). Patellofemoral loads generally increased as knee flexion increased and decreased as knee flexion decreased. To gradually increase patellofemoral loads, per...
International Journal of Sports Physical Therapy, 2022
Background Forward and side lunge exercises strengthen hip and thigh musculature, enhance patello... more Background Forward and side lunge exercises strengthen hip and thigh musculature, enhance patellofemoral joint stability, and are commonly used during patellofemoral rehabilitation and training for sport. Hypothesis/Purpose The purpose was to quantify, via calculated estimates, patellofemoral force and stress between two lunge type variations (forward lunge versus side lunge) and between two step height variations (ground level versus 10 cm platform). The hypotheses were that patellofemoral force and stress would be greater at all knee angles performing the bodyweight side lunge compared to the bodyweight forward lunge, and greater when performing the forward and side lunge at ground level compared to up a 10cm platform. Study Design Controlled laboratory biomechanics repeated measures, counterbalanced design. Methods Sixteen participants performed a forward and side lunge at ground level and up a 10cm platform. Electromyographic, ground reaction force, and kinematic variables were collected and input into a biomechanical optimization model, and patellofemoral joint force and stress were calculated as a function of knee angle during the lunge descent and ascent and assessed with a repeated measures 2-way ANOVA (p<0.05).
Journal of Orthopaedic & Sports Physical Therapy, 2010
Core Muscle Activation During Swiss Ball and Traditional Abdominal Exercises t he "core" has been... more Core Muscle Activation During Swiss Ball and Traditional Abdominal Exercises t he "core" has been used to refer to the lumbopelvic-hip complex, which involves deeper muscles, such as the internal oblique, transversus abdominis, transversospinalis (multifidus, rotatores, semispinalis), quadratus lumborum, and psoas major and minor, and superficial muscles, such as the rectus abdominis, external oblique, erector spinae (iliocostalis, spinalis, longissimus),
Kinematic and kinetic comparison betweein American and Korean professional baseball pitchers / Rafael Escamilla ...[et al.]
International Journal of Sports Physical Therapy, 2016
In spite of the bodyblade (BB®) being used in clinical settings during shoulder and trunk rehabil... more In spite of the bodyblade (BB®) being used in clinical settings during shoulder and trunk rehabilitation and training for 24 years, there are only five known scientific papers that have described muscle recruitment patterns using the BB®. Moreover, there are no known studies that have examined muscle activity differences between males and females (who both use the bodyblade in the clinic) or between different BB® devices. The primary purposes of this investigation were to compare glenohumeral and scapular muscle activity between the Bodyblade® Pro (BB®P) and Bodyblade® Classic (BB®C) devices while performing a variety of exercises, as well as to compare muscle activity between males and females. It was hypothesized that glenohumeral and scapular muscle activity would be significantly greater in females compared to males, significantly greater while performing exercises with the BB®P compared to the BB®C, significantly different among various BB® exercises, and greater with two hand ...
Journal of Sports Science and Medicine, Oct 1, 2007
The purpose of this study was to compare the kinematics of kuzushi/tsukuri (KT) phases of the har... more The purpose of this study was to compare the kinematics of kuzushi/tsukuri (KT) phases of the harai-goshi throw under competitive and non-competitive conditions. A third degree black belt subject served as the tori (thrower) for both conditions. Two black belt participants ranked as first degree and fourth degree served as the uke (faller) for the competitive and non-competitive conditions, respectively. Two video cameras (JVC 60 Hz) and a three dimensional motion analysis system (Vicon-Peak Performance Technologies, Inc., Englewood, CO) were used to collect and analyze peak velocity for the center of mass (COM) of uke and tori and peak angular velocity of tori's trunk (TAV). Data were smoothed using a 4(th) order zero lag Butterworth filter with a cut-off frequency set by the Peak software optimization technique. All variables were normalized by time as a percentage of the KT phase. In general, the COM directional velocity patterns were similar between conditions. Uke's def...
Journal of Sports Science and Medicine, Jul 1, 2006
Four black belt throwers (tori) and one black belt faller (uke) were filmed and analyzed in three... more Four black belt throwers (tori) and one black belt faller (uke) were filmed and analyzed in three-dimensions using two video cameras (JVC 60 Hz) and motion analysis software. Average linear momentum in the anteroposterior (x), vertical (y), and mediolateral (z) directions and average resultant impulse of uke's center of mass (COM) were investigated for three different throwing techniques; harai-goshi (hip throw), seoi-nage (hand throw), and osoto-gari (leg throw). Each throw was broken down into three main phases; kuzushi (balance breaking), tsukuri (fit-in), and kake (throw). For the harai-goshi and osoto-gari throws, impulse measurements were the largest within kuzushi and tsukuri phases (where collision between tori and uke predominantly occurs). Both throws indicated an importance for tori to create large momentum prior to contact with uke. The seoi-nage throw demonstrated the lowest impulse and maintained forward momentum on the body of uke throughout the entire throw. The ...