freestyle: an implication of the knee and ankle joint injury prevention 希羅式與自由式摔角於防禦擒抱之力動學與運動學:應用... more freestyle: an implication of the knee and ankle joint injury prevention 希羅式與自由式摔角於防禦擒抱之力動學與運動學:應用於膝關節與踝關節傷害預防 Tsong-Rong Jang, Sheng-Chang Chen, Yang-Chieh Fu, Tsung-Jung Ho, and Tung-Wu Lu Athletics Department and Graduate School, National Taiwan Sport University, Taichung, Taiwan Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan College of Chinese Medicine, China Medical University, Taichung, Taiwan Chinese Medicine Deparment , China Medical University Beigang Hospital, Taiwan
Objectives: To measure in vivo three-dimensional kinematics of the mandible and associated end-po... more Objectives: To measure in vivo three-dimensional kinematics of the mandible and associated end-point trajectories and to quantify their relationships during temporomandibular joint activities using 3D fluoroscopy. Methods: A novel fluoroscopy-based 3D measurement method was used to measure motions of the mandible and the associated end points (i.e. incisors and lateral poles of both condyles) during open close, lateral gliding and protrusion-retraction movements in healthy young individuals. The contributions of each of the rotational and translational components of the mandible to the end-point trajectories were quantified through experiment-based computer simulations. Results: The mandibular rotation was found to account for 91% of the maximal mouthopening-capacity and 73% of the maximal lateral incisor movement, while the condylar translation contributed to 99% of the anterior protrusion distance. Incisor trajectories were nearly vertical within the first 60% of the maximal opening during the open-close movement. Conclusions: Similar condylar downward rotation paths but with bilaterally asymmetrical ranges were used to perform basic mandibular movements of different targeted TI trajectories in three dimensions, that is, open-close, lateral-gliding and protrusion-retraction. Mandibular rotations contributed to the majority of the principal displacement components of the incisor, that is, vertical during open-close and towards the working-side-during lateral-gliding, while mandibular translation contributed mainly to the forward movement of the incisor during protrusion-retraction. Owing to the anatomical constraints, the freedom of mandibular translation is limited and mainly in the anteroposterior direction, which is considered helpful for the control and stability of the TMJ during oral activities.
International Journal of Kinesiology and Sports Science, 2015
The purpose of this study was to investigate the effects of general and specific warm-up protocol... more The purpose of this study was to investigate the effects of general and specific warm-up protocols on rate of force development (RFD), relative RFD (rRFD), ground reaction force (GRF) and relative ground reaction force (rGRF) during an isometric mid-thigh pull (IMTP), after WBV exposure. Methods: Fifteen healthy recreationally trained males (age: 24.1 ± 2.3 yrs, height: 72.9 ± 7.8 cm; mass: 86.9 ± 8.3) completed five protocols: baseline, isometric vibration (iVib), isometric no vibration (iNV), dynamic vibration (dVib) and dynamic no vibration (dNV). The baseline was completed without any warm-up prior to the IMTP. The intervention protocols had the same prescription of 4 sets of 30-second bouts of quarter squats (dynamic [DQS] and isometric [IQS]) on the WBV platform with or without vibration. Following a one-minute rest period after each protocol, participants completed three maximal IMTPs. Results: Repeated measures ANOVA with a Bonferroni post hoc demonstrated that RFD in dNV (7657.8 ± 2292.5 N/s) was significantly greater than iVib (7156.4 ± 2170.0 N/s). However, the other experimental trials for RFD demonstrated no significant differences (p>0.05). There were also no significant differences for rRFD, GRF or rGRF between protocols. Conclusion: These results demonstrate that a dynamic warm-up without WBV elicits greater RFD than an isometric warm-up with WBV prior to a maximal isometric exercise. Further research needs to be investigated utilizing dynamic and isometric warm-ups in conjunction with WBV and power output.
Objective: To evaluate examiner variability in a superficial skin marker model of canine stifle k... more Objective: To evaluate examiner variability in a superficial skin marker model of canine stifle kinematics. Study Design: Experimental. Animals: Six clinically normal dogs. Methods: Dogs had 11 retroreflective markers fixed to the skin on the right hindlimb. Dogs were trotted 5 times through the calibrated testing space and this was repeated on 4 different testing days. Examiner A applied all markers to a dog and collected 6 good trials for analysis. The markers were then removed and Examiner B immediately repeated the process on the same dog. This was repeated for each dog on the 4 testing days. The dogs were trotted at a velocity of 1.70-2.10 m/s through the testing space to obtain the dynamic data sets. Comparisons were performed with Fourier analysis and Generalized Indicator Function Analysis (GIFA). Significance was set at P <.05 for all comparisons. Results: Fourier analysis and GIFA found differences within and between examiners. Fourier analysis found no differences in sagittal and transverse planes for the experienced (A) and novice examiner (B), respectively. Fourier analysis detected fewer differences for the experienced examiner (A). Conclusion: Variability occurs within and between examiners using the same kinematic model. Transverse and frontal plane kinematics produce variable results between examiners. Prior experience with the model reduces the amount of variability and results in consistent and repeatable sagittal plane kinematic data collection.
Objective: To model the kinematics of the canine stifle in 3 dimensions using the Joint Coordinat... more Objective: To model the kinematics of the canine stifle in 3 dimensions using the Joint Coordinate System (JCS) and compare the JCS method with linear and segmental models. Study Design: In vivo biomechanical study. Animals: Normal adult mixed breed dogs (n = 6). Methods: Dogs had 10 retroreflective markers affixed to the skin on the right pelvic limb. Dogs were walked and trotted 5 times through the calibrated space and the procedure was repeated 5 days later. Sagittal flexion and extension angle waveforms acquired during each trial with all 3 models (JCS, Linear, and Segmental) were produced simultaneously during each gait. The JCS method provided additional internal/external and abduction/adduction angles. Comparison of sagittal flexion and extension angle waveforms was performed with generalized indicator function analysis (GIFA) and Fourier analysis. A normalization procedure was performed. Results: Each model provided consistent equivalent sagittal flexion-extension data. The JCS provided consistent additional internal/external and abduction/adduction. Sagittal waveform differences were found between methods and testing days for each dog at a walk and a trot with both GIFA and Fourier analysis. After normalization, differences were less with Fourier analysis and were unaltered with GIFA. Conclusions: Whereas all methods produced similar flexion-extension waveforms, JCS provided additional valuable data. Clinical Relevance: The JCS model provided sagittal plane flexion/extension data as well as internal/external rotation and abduction/adduction data.
An accurate, non-invasive method for in vivo bone position determination is essential for the stu... more An accurate, non-invasive method for in vivo bone position determination is essential for the study of joint kinematics. Previous studies using skin markers on body segments to determine the underlying bone positions are prone to errors due to undesired motion between the ...
The purpose of this paper is to design an image-based platform for real-time dispatching of multi... more The purpose of this paper is to design an image-based platform for real-time dispatching of multi-robots, in the context of, for example, supporting a courier transportation system. With this integration platform, we are able to compare efficiencies with different dispatching policies. With the global information regarding the robots and pick-up points available from the image process, this real-time dispatching platform
Swing velocity has been considered as one of the essential factors of bat swing biomechanics, and... more Swing velocity has been considered as one of the essential factors of bat swing biomechanics, and traditionally coaches and players think it can be altered by using a differently weighted bat for warm-up before an at bat. The purpose of this study was to examine the effects of 3 differently weighted warm-up bats on 3D linear and angular kinematics. Ten female varsity softball players were recruited and bat swing kinematics with normal (NW), heavy (HW), and light (LW) weighted warm-up bats were collected. Both linear and angular kinematic variables were compared between different bat weights using RMANOVA. Only 1 velocity variable difference between LW and NW, and 4 temporal differences between HW and NW were found. It is suggested that in general, swing kinematics is not altered by differently weighted bats warm-up prior maximal swing.
Survivor rates of unicompartmental knee arthroplasty (UKA) vary, and reasons for this phenomenon ... more Survivor rates of unicompartmental knee arthroplasty (UKA) vary, and reasons for this phenomenon are not clear. Biomechanically, knee joint kinematics affect physical function and long-term survivorship. Therefore, the goal of the first study was to compare, the in-vivo tibio-femoral kinematics displayed during a step-up task stair ascent of lateral (LAT) and medial (MED) UKA users. The purpose of the second study was to compare the biomechanics of LAT- and MED-UKA users to control (CON) participants for stair ascent. Fourteen MED-UKA and eight LAT-UKA (N = 22), participants were recruited in the first study. Twenty-six UKA participants (17 MED- and 9 LAT-UKA) participated in the second study, and 26 healthy matched participants were recruited. UKA participants received a CT scan of the operative knee, and the knee kinematics during step-up motion was measured using videofluoroscopy system in the first study. For Study 2, all participants performed stair ascent, and kinematics and k...
Objectives: To measure in vivo three-dimensional kinematics of the mandible and associated end-po... more Objectives: To measure in vivo three-dimensional kinematics of the mandible and associated end-point trajectories and to quantify their relationships during temporomandibular joint activities using 3D fluoroscopy. Methods: A novel fluoroscopy-based 3D measurement method was used to measure motions of the mandible and the associated end points (i.e. incisors and lateral poles of both condyles) during open close, lateral gliding and protrusion-retraction movements in healthy young individuals. The contributions of each of the rotational and translational components of the mandible to the end-point trajectories were quantified through experiment-based computer simulations. Results: The mandibular rotation was found to account for 91% of the maximal mouth-opening-capacity and 73% of the maximal lateral incisor movement, while the condylar translation contributed to 99% of the anterior protrusion distance. Incisor trajectories were nearly vertical within the first 60% of the maximal open...
Background: The purpose of the study was to assess the postural stability and complexity of postu... more Background: The purpose of the study was to assess the postural stability and complexity of postural control for moderately physically active individuals with spinal fusion for adolescent idiopathic scoliosis at two years postoperation. Methods: Limit of stability test and sensory organization test were conducted for 10 moderately physically-active participants with spinal fusion and 10 controls pair-matched for mass, height and physical activity level. During the limit of stability test, participants were instructed to lean the center of gravity as far as possible toward 8 predetermined directions and the maximum excursion and direction control were analyzed. During the sensory organization test, participants were instructed to maintain as still as possible in six test conditions and equilibrium scores and sway area of center of pressure were analyzed. Multi-scale entropy of center of pressure was calculated to quantify sway complexity. Findings: Most postural stability outcomes of spinal fusion participants were comparable to controls except for significantly reduced equilibrium scores (p = 0.039, partial η 2 = 0.217). Moreover, spinal fusion participants exhibited tendencies of reduced direction control (p = 0.053) during the limit of stability test and greater sway area (p = 0.052) during the sensory organization test. Interpretation: Although the center of gravity control might be affected, spinal fusion individuals who were moderately physically active likely progressively learned to adapt postoperatively to their fused spine to meet the postural demands required when performing physical movements. We suggest that spinal fusion is a satisfactory treatment in regard to the recovery of postural stability.
The purpose of the study was to determine if the intratrunk coordination of axial rotation exhibi... more The purpose of the study was to determine if the intratrunk coordination of axial rotation exhibited by individuals with spinal fusion for adolescent idiopathic scoliosis (SF-AIS) during running varies from healthy individuals and how the coordination differs among adjacent trunk-segment pairs. Axial rotations of trunk segments (upper, middle, lower trunk) and pelvis were collected for 11 SF-AIS participants and 11 matched controls during running. Cross-correlation determined the phase lag between the adjacent segment motions. The coupling angle was generated using the vector coding method and classified into 1 of the 4 major, modified coordination patterns: in-phase, anti-phase, superior, and inferior phase. Two-way, mixed-model ANCOVA was employed to test phase lag, cross-correlation r, and time spent in each major coordination pattern. A significantly lower phase lag for SF-AIS was observed compared with controls. Qualitatively, there was a tendency that SF-AIS participants spent...
International Journal of Kinesiology and Sports Science
The purpose of this study was to investigate the effects of a self-adapted, jaw repositioning mou... more The purpose of this study was to investigate the effects of a self-adapted, jaw repositioning mouthpiece and jaw clenching on muscle activity during the countermovement vertical jump (CMVJ) and isometric mid-thigh clean pull (MTCP). Methods: Thirty-six healthy, recreationally trained males (n=36; age, 23 ± 2.8 years; height, 178.54 ± 9.0 cm; body mass, 83.09 ± 7.8 kg) completed maximal CMVJ and MTCP assessments under six experimental conditions: jaw repositioning mouthpiece plus clenching (MP+C), jaw repositioning mouthpiece with jaw relaxed (MP), traditional mouthguard plus clenching (MG+C), traditional mouthguard with jaw relaxed (MG), no mouthpiece plus clenching (NoMP+C) and no mouthpiece with jaw relaxed (NoMP) while muscle activity of the dominant leg medial gastrocnemius (G), medial hamstring (H), vastus medialis (VMO), and erector spinae (ES) was recorded. Results: Repeated measures ANOVA revealed no changes in MTCP muscle activation for any mouthpiece or clench condition. Jaw clenching, regardless of mouthpiece condition, significantly improved prime mover muscle activation during CMVJ (p < .001). Prime mover muscle activation was significantly greater during CMVJ assessment for jaw repositioning mouthpiece and no mouthpiece conditions over the use of a traditional mouthguard (p < .001), but the repositioning mouthpiece did not lead to improved muscle activation compared to no mouthpiece (p > .05). Conclusion: These findings support jaw clenching as a viable technique to elicit concurrent activation potentiation (CAP) of prime mover muscle activity during dynamic but not isometric physical activity.
Journal of strength and conditioning research, Jan 31, 2017
This study examined the effects of jaw clenching, and a self-adapted, jaw repositioning mouthpiec... more This study examined the effects of jaw clenching, and a self-adapted, jaw repositioning mouthpiece on force production during maximum countermovement vertical jump and maximum isometric mid-thigh clean pull assessments in an attempt to determine any ergogenic effects attributable to clenching, jaw repositioning mouthpiece use, or the combination of both. Thirty-six male subjects performed vertical jump and isometric clean pull assessments from a force platform under various mouthpiece and clench conditions. A 3x2 (mouthpiece x clench) repeated measures ANOVA was conducted to analyze each of the following force production variables for both assessments: peak force, normalized peak force, and rate of force development. Additionally, jump height was analyzed for the vertical jump. Results revealed improvements in peak force (F1,35 = 15.84, p < 0.001, ηp= 0.31), normalized peak force (F1,35 = 16.28, p < 0.001, ηp= 0.32), and rate of force development (F1,35 = 12.89, p = 0.001, ηp=...
To report a method of evaluating 3-dimensional joint motion in dogs with a stifle orthosis. Exper... more To report a method of evaluating 3-dimensional joint motion in dogs with a stifle orthosis. Experimental. Six healthy dogs. Three-dimensional pelvic limb joint motion was recorded with and without a stifle orthosis. Kinematic data were collected from dogs at a walk and trot for the hip, stifle, and tarsus prior to, and after application of, a stifle orthosis. Data were also obtained for the orthosis alone. Comparisons were made between the braced and unbraced limb, and between the braced limb and the orthosis alone. Complete waveforms, kinematic, and temporospatial variables were compared. Gait waveforms differed between braced and unbraced limbs for all joints and planes of motion (P < .05), as well as between the braced stifles and the orthosis alone at both a walk and trot. However, joint ROM was inconsistently altered. The effect of bracing on stifle ROM was limited to a reduced extension at the end of stance. Adjacent joint ROM was affected by the stifle orthosis. Temporospa...
Page 1. A PROPHYLACTIC ANKLE BRACE ALTERS LOWER EXTREMITY KINEMATICS DURING DROP LANDINGS Jae P. ... more Page 1. A PROPHYLACTIC ANKLE BRACE ALTERS LOWER EXTREMITY KINEMATICS DURING DROP LANDINGS Jae P. Yom, Yang-Chieh Fu, Scott W. Arnett, Bradley Bowser, Maggie Law, Ryan E. Embertson, Sean ...
freestyle: an implication of the knee and ankle joint injury prevention 希羅式與自由式摔角於防禦擒抱之力動學與運動學:應用... more freestyle: an implication of the knee and ankle joint injury prevention 希羅式與自由式摔角於防禦擒抱之力動學與運動學:應用於膝關節與踝關節傷害預防 Tsong-Rong Jang, Sheng-Chang Chen, Yang-Chieh Fu, Tsung-Jung Ho, and Tung-Wu Lu Athletics Department and Graduate School, National Taiwan Sport University, Taichung, Taiwan Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan College of Chinese Medicine, China Medical University, Taichung, Taiwan Chinese Medicine Deparment , China Medical University Beigang Hospital, Taiwan
Objectives: To measure in vivo three-dimensional kinematics of the mandible and associated end-po... more Objectives: To measure in vivo three-dimensional kinematics of the mandible and associated end-point trajectories and to quantify their relationships during temporomandibular joint activities using 3D fluoroscopy. Methods: A novel fluoroscopy-based 3D measurement method was used to measure motions of the mandible and the associated end points (i.e. incisors and lateral poles of both condyles) during open close, lateral gliding and protrusion-retraction movements in healthy young individuals. The contributions of each of the rotational and translational components of the mandible to the end-point trajectories were quantified through experiment-based computer simulations. Results: The mandibular rotation was found to account for 91% of the maximal mouthopening-capacity and 73% of the maximal lateral incisor movement, while the condylar translation contributed to 99% of the anterior protrusion distance. Incisor trajectories were nearly vertical within the first 60% of the maximal opening during the open-close movement. Conclusions: Similar condylar downward rotation paths but with bilaterally asymmetrical ranges were used to perform basic mandibular movements of different targeted TI trajectories in three dimensions, that is, open-close, lateral-gliding and protrusion-retraction. Mandibular rotations contributed to the majority of the principal displacement components of the incisor, that is, vertical during open-close and towards the working-side-during lateral-gliding, while mandibular translation contributed mainly to the forward movement of the incisor during protrusion-retraction. Owing to the anatomical constraints, the freedom of mandibular translation is limited and mainly in the anteroposterior direction, which is considered helpful for the control and stability of the TMJ during oral activities.
International Journal of Kinesiology and Sports Science, 2015
The purpose of this study was to investigate the effects of general and specific warm-up protocol... more The purpose of this study was to investigate the effects of general and specific warm-up protocols on rate of force development (RFD), relative RFD (rRFD), ground reaction force (GRF) and relative ground reaction force (rGRF) during an isometric mid-thigh pull (IMTP), after WBV exposure. Methods: Fifteen healthy recreationally trained males (age: 24.1 ± 2.3 yrs, height: 72.9 ± 7.8 cm; mass: 86.9 ± 8.3) completed five protocols: baseline, isometric vibration (iVib), isometric no vibration (iNV), dynamic vibration (dVib) and dynamic no vibration (dNV). The baseline was completed without any warm-up prior to the IMTP. The intervention protocols had the same prescription of 4 sets of 30-second bouts of quarter squats (dynamic [DQS] and isometric [IQS]) on the WBV platform with or without vibration. Following a one-minute rest period after each protocol, participants completed three maximal IMTPs. Results: Repeated measures ANOVA with a Bonferroni post hoc demonstrated that RFD in dNV (7657.8 ± 2292.5 N/s) was significantly greater than iVib (7156.4 ± 2170.0 N/s). However, the other experimental trials for RFD demonstrated no significant differences (p>0.05). There were also no significant differences for rRFD, GRF or rGRF between protocols. Conclusion: These results demonstrate that a dynamic warm-up without WBV elicits greater RFD than an isometric warm-up with WBV prior to a maximal isometric exercise. Further research needs to be investigated utilizing dynamic and isometric warm-ups in conjunction with WBV and power output.
Objective: To evaluate examiner variability in a superficial skin marker model of canine stifle k... more Objective: To evaluate examiner variability in a superficial skin marker model of canine stifle kinematics. Study Design: Experimental. Animals: Six clinically normal dogs. Methods: Dogs had 11 retroreflective markers fixed to the skin on the right hindlimb. Dogs were trotted 5 times through the calibrated testing space and this was repeated on 4 different testing days. Examiner A applied all markers to a dog and collected 6 good trials for analysis. The markers were then removed and Examiner B immediately repeated the process on the same dog. This was repeated for each dog on the 4 testing days. The dogs were trotted at a velocity of 1.70-2.10 m/s through the testing space to obtain the dynamic data sets. Comparisons were performed with Fourier analysis and Generalized Indicator Function Analysis (GIFA). Significance was set at P <.05 for all comparisons. Results: Fourier analysis and GIFA found differences within and between examiners. Fourier analysis found no differences in sagittal and transverse planes for the experienced (A) and novice examiner (B), respectively. Fourier analysis detected fewer differences for the experienced examiner (A). Conclusion: Variability occurs within and between examiners using the same kinematic model. Transverse and frontal plane kinematics produce variable results between examiners. Prior experience with the model reduces the amount of variability and results in consistent and repeatable sagittal plane kinematic data collection.
Objective: To model the kinematics of the canine stifle in 3 dimensions using the Joint Coordinat... more Objective: To model the kinematics of the canine stifle in 3 dimensions using the Joint Coordinate System (JCS) and compare the JCS method with linear and segmental models. Study Design: In vivo biomechanical study. Animals: Normal adult mixed breed dogs (n = 6). Methods: Dogs had 10 retroreflective markers affixed to the skin on the right pelvic limb. Dogs were walked and trotted 5 times through the calibrated space and the procedure was repeated 5 days later. Sagittal flexion and extension angle waveforms acquired during each trial with all 3 models (JCS, Linear, and Segmental) were produced simultaneously during each gait. The JCS method provided additional internal/external and abduction/adduction angles. Comparison of sagittal flexion and extension angle waveforms was performed with generalized indicator function analysis (GIFA) and Fourier analysis. A normalization procedure was performed. Results: Each model provided consistent equivalent sagittal flexion-extension data. The JCS provided consistent additional internal/external and abduction/adduction. Sagittal waveform differences were found between methods and testing days for each dog at a walk and a trot with both GIFA and Fourier analysis. After normalization, differences were less with Fourier analysis and were unaltered with GIFA. Conclusions: Whereas all methods produced similar flexion-extension waveforms, JCS provided additional valuable data. Clinical Relevance: The JCS model provided sagittal plane flexion/extension data as well as internal/external rotation and abduction/adduction data.
An accurate, non-invasive method for in vivo bone position determination is essential for the stu... more An accurate, non-invasive method for in vivo bone position determination is essential for the study of joint kinematics. Previous studies using skin markers on body segments to determine the underlying bone positions are prone to errors due to undesired motion between the ...
The purpose of this paper is to design an image-based platform for real-time dispatching of multi... more The purpose of this paper is to design an image-based platform for real-time dispatching of multi-robots, in the context of, for example, supporting a courier transportation system. With this integration platform, we are able to compare efficiencies with different dispatching policies. With the global information regarding the robots and pick-up points available from the image process, this real-time dispatching platform
Swing velocity has been considered as one of the essential factors of bat swing biomechanics, and... more Swing velocity has been considered as one of the essential factors of bat swing biomechanics, and traditionally coaches and players think it can be altered by using a differently weighted bat for warm-up before an at bat. The purpose of this study was to examine the effects of 3 differently weighted warm-up bats on 3D linear and angular kinematics. Ten female varsity softball players were recruited and bat swing kinematics with normal (NW), heavy (HW), and light (LW) weighted warm-up bats were collected. Both linear and angular kinematic variables were compared between different bat weights using RMANOVA. Only 1 velocity variable difference between LW and NW, and 4 temporal differences between HW and NW were found. It is suggested that in general, swing kinematics is not altered by differently weighted bats warm-up prior maximal swing.
Survivor rates of unicompartmental knee arthroplasty (UKA) vary, and reasons for this phenomenon ... more Survivor rates of unicompartmental knee arthroplasty (UKA) vary, and reasons for this phenomenon are not clear. Biomechanically, knee joint kinematics affect physical function and long-term survivorship. Therefore, the goal of the first study was to compare, the in-vivo tibio-femoral kinematics displayed during a step-up task stair ascent of lateral (LAT) and medial (MED) UKA users. The purpose of the second study was to compare the biomechanics of LAT- and MED-UKA users to control (CON) participants for stair ascent. Fourteen MED-UKA and eight LAT-UKA (N = 22), participants were recruited in the first study. Twenty-six UKA participants (17 MED- and 9 LAT-UKA) participated in the second study, and 26 healthy matched participants were recruited. UKA participants received a CT scan of the operative knee, and the knee kinematics during step-up motion was measured using videofluoroscopy system in the first study. For Study 2, all participants performed stair ascent, and kinematics and k...
Objectives: To measure in vivo three-dimensional kinematics of the mandible and associated end-po... more Objectives: To measure in vivo three-dimensional kinematics of the mandible and associated end-point trajectories and to quantify their relationships during temporomandibular joint activities using 3D fluoroscopy. Methods: A novel fluoroscopy-based 3D measurement method was used to measure motions of the mandible and the associated end points (i.e. incisors and lateral poles of both condyles) during open close, lateral gliding and protrusion-retraction movements in healthy young individuals. The contributions of each of the rotational and translational components of the mandible to the end-point trajectories were quantified through experiment-based computer simulations. Results: The mandibular rotation was found to account for 91% of the maximal mouth-opening-capacity and 73% of the maximal lateral incisor movement, while the condylar translation contributed to 99% of the anterior protrusion distance. Incisor trajectories were nearly vertical within the first 60% of the maximal open...
Background: The purpose of the study was to assess the postural stability and complexity of postu... more Background: The purpose of the study was to assess the postural stability and complexity of postural control for moderately physically active individuals with spinal fusion for adolescent idiopathic scoliosis at two years postoperation. Methods: Limit of stability test and sensory organization test were conducted for 10 moderately physically-active participants with spinal fusion and 10 controls pair-matched for mass, height and physical activity level. During the limit of stability test, participants were instructed to lean the center of gravity as far as possible toward 8 predetermined directions and the maximum excursion and direction control were analyzed. During the sensory organization test, participants were instructed to maintain as still as possible in six test conditions and equilibrium scores and sway area of center of pressure were analyzed. Multi-scale entropy of center of pressure was calculated to quantify sway complexity. Findings: Most postural stability outcomes of spinal fusion participants were comparable to controls except for significantly reduced equilibrium scores (p = 0.039, partial η 2 = 0.217). Moreover, spinal fusion participants exhibited tendencies of reduced direction control (p = 0.053) during the limit of stability test and greater sway area (p = 0.052) during the sensory organization test. Interpretation: Although the center of gravity control might be affected, spinal fusion individuals who were moderately physically active likely progressively learned to adapt postoperatively to their fused spine to meet the postural demands required when performing physical movements. We suggest that spinal fusion is a satisfactory treatment in regard to the recovery of postural stability.
The purpose of the study was to determine if the intratrunk coordination of axial rotation exhibi... more The purpose of the study was to determine if the intratrunk coordination of axial rotation exhibited by individuals with spinal fusion for adolescent idiopathic scoliosis (SF-AIS) during running varies from healthy individuals and how the coordination differs among adjacent trunk-segment pairs. Axial rotations of trunk segments (upper, middle, lower trunk) and pelvis were collected for 11 SF-AIS participants and 11 matched controls during running. Cross-correlation determined the phase lag between the adjacent segment motions. The coupling angle was generated using the vector coding method and classified into 1 of the 4 major, modified coordination patterns: in-phase, anti-phase, superior, and inferior phase. Two-way, mixed-model ANCOVA was employed to test phase lag, cross-correlation r, and time spent in each major coordination pattern. A significantly lower phase lag for SF-AIS was observed compared with controls. Qualitatively, there was a tendency that SF-AIS participants spent...
International Journal of Kinesiology and Sports Science
The purpose of this study was to investigate the effects of a self-adapted, jaw repositioning mou... more The purpose of this study was to investigate the effects of a self-adapted, jaw repositioning mouthpiece and jaw clenching on muscle activity during the countermovement vertical jump (CMVJ) and isometric mid-thigh clean pull (MTCP). Methods: Thirty-six healthy, recreationally trained males (n=36; age, 23 ± 2.8 years; height, 178.54 ± 9.0 cm; body mass, 83.09 ± 7.8 kg) completed maximal CMVJ and MTCP assessments under six experimental conditions: jaw repositioning mouthpiece plus clenching (MP+C), jaw repositioning mouthpiece with jaw relaxed (MP), traditional mouthguard plus clenching (MG+C), traditional mouthguard with jaw relaxed (MG), no mouthpiece plus clenching (NoMP+C) and no mouthpiece with jaw relaxed (NoMP) while muscle activity of the dominant leg medial gastrocnemius (G), medial hamstring (H), vastus medialis (VMO), and erector spinae (ES) was recorded. Results: Repeated measures ANOVA revealed no changes in MTCP muscle activation for any mouthpiece or clench condition. Jaw clenching, regardless of mouthpiece condition, significantly improved prime mover muscle activation during CMVJ (p < .001). Prime mover muscle activation was significantly greater during CMVJ assessment for jaw repositioning mouthpiece and no mouthpiece conditions over the use of a traditional mouthguard (p < .001), but the repositioning mouthpiece did not lead to improved muscle activation compared to no mouthpiece (p > .05). Conclusion: These findings support jaw clenching as a viable technique to elicit concurrent activation potentiation (CAP) of prime mover muscle activity during dynamic but not isometric physical activity.
Journal of strength and conditioning research, Jan 31, 2017
This study examined the effects of jaw clenching, and a self-adapted, jaw repositioning mouthpiec... more This study examined the effects of jaw clenching, and a self-adapted, jaw repositioning mouthpiece on force production during maximum countermovement vertical jump and maximum isometric mid-thigh clean pull assessments in an attempt to determine any ergogenic effects attributable to clenching, jaw repositioning mouthpiece use, or the combination of both. Thirty-six male subjects performed vertical jump and isometric clean pull assessments from a force platform under various mouthpiece and clench conditions. A 3x2 (mouthpiece x clench) repeated measures ANOVA was conducted to analyze each of the following force production variables for both assessments: peak force, normalized peak force, and rate of force development. Additionally, jump height was analyzed for the vertical jump. Results revealed improvements in peak force (F1,35 = 15.84, p < 0.001, ηp= 0.31), normalized peak force (F1,35 = 16.28, p < 0.001, ηp= 0.32), and rate of force development (F1,35 = 12.89, p = 0.001, ηp=...
To report a method of evaluating 3-dimensional joint motion in dogs with a stifle orthosis. Exper... more To report a method of evaluating 3-dimensional joint motion in dogs with a stifle orthosis. Experimental. Six healthy dogs. Three-dimensional pelvic limb joint motion was recorded with and without a stifle orthosis. Kinematic data were collected from dogs at a walk and trot for the hip, stifle, and tarsus prior to, and after application of, a stifle orthosis. Data were also obtained for the orthosis alone. Comparisons were made between the braced and unbraced limb, and between the braced limb and the orthosis alone. Complete waveforms, kinematic, and temporospatial variables were compared. Gait waveforms differed between braced and unbraced limbs for all joints and planes of motion (P < .05), as well as between the braced stifles and the orthosis alone at both a walk and trot. However, joint ROM was inconsistently altered. The effect of bracing on stifle ROM was limited to a reduced extension at the end of stance. Adjacent joint ROM was affected by the stifle orthosis. Temporospa...
Page 1. A PROPHYLACTIC ANKLE BRACE ALTERS LOWER EXTREMITY KINEMATICS DURING DROP LANDINGS Jae P. ... more Page 1. A PROPHYLACTIC ANKLE BRACE ALTERS LOWER EXTREMITY KINEMATICS DURING DROP LANDINGS Jae P. Yom, Yang-Chieh Fu, Scott W. Arnett, Bradley Bowser, Maggie Law, Ryan E. Embertson, Sean ...
Purpose: The purpose of this study was to investigate the effects of general and specific warm-up... more Purpose: The purpose of this study was to investigate the effects of general and specific warm-up protocols on rate of force development (RFD), relative RFD (rRFD), ground reaction force (GRF) and relative ground reaction force (rGRF) during an isometric mid-thigh pull (IMTP), after WBV exposure. Methods: Fifteen healthy recreationally trained males (age: 24.1 ± 2.3 yrs, height: 72.9 ± 7.8 cm; mass: 86.9 ± 8.3) completed five protocols: baseline, isometric vibration (iVib), isometric no vibration (iNV), dynamic vibration (dVib) and dynamic no vibration (dNV). The baseline was completed without any warm-up prior to the IMTP. The intervention protocols had the same prescription of 4 sets of 30-second bouts of quarter squats (dynamic [DQS] and isometric [IQS]) on the WBV platform with or without vibration. Following a one-minute rest period after each protocol, participants completed three maximal IMTPs. Results: Repeated measures ANOVA with a Bonferroni post hoc demonstrated that RFD in dNV (7657.8 ± 2292.5 N/s) was significantly greater than iVib (7156.4 ± 2170.0 N/s). However, the other experimental trials for RFD demonstrated no significant differences (p>0.05). There were also no significant differences for rRFD, GRF or rGRF between protocols. Conclusion: These results demonstrate that a dynamic warm-up without WBV elicits greater RFD than an isometric warm-up with WBV prior to a maximal isometric exercise. Further research needs to be investigated utilizing dynamic and isometric warm-ups in conjunction with WBV and power output.
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Papers by Yang-Chieh Fu