Effect of pressure on the internal rotation angle of biphenyl in carbon disulfide

1988 ◽  
Vol 89 (9) ◽  
pp. 5417-5421 ◽  
Author(s):  
Minoru Katō ◽  
Mikio Higashi ◽  
Yoshihiro Taniguchi
Keyword(s):  
Internal Rotation ◽  
Carbon Disulfide ◽  
Rotation Angle ◽  
Effect Of Pressure ◽  
Internal Rotation Angle

scholarly journals The Effects of Gluteal Strength and Activation on the Relationship Between Femoral Alignment and Functional Valgus Collapse During a Single-Leg Landing

2021 ◽  
pp. 1-10
Author(s):  
Jennifer A. Hogg ◽  
Terry Ackerman ◽  
Anh-Dung Nguyen ◽  
Scott E. Ross ◽  
Randy J. Schmitz ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Muscle Activation ◽  
Rotation Angle ◽  
Critical Role ◽  
Future Research ◽  
Mediation Effects ◽  
Peak Knee ◽  
Hip Abduction ◽  
Internal Rotation Angle ◽  
Abduction Strength

Context: A bias toward femoral internal rotation is a potential precursor to functional valgus collapse. The gluteal muscles may play a critical role in mitigating these effects. Objective: Determine the extent to which gluteal strength and activation mediate associations between femoral alignment measures and functional valgus collapse. Design: Cross-sectional. Setting: Research laboratory. Patients or Other Participants: Forty-five females (age = 20.1 [1.7] y; height = 165.2 [7.6] cm; weight = 68.6 [13.1] kg) and 45 males (age = 20.8 [2.0] y; height = 177.5 [8.7] cm; weight = 82.7 [16.5] kg), healthy for 6 months prior. Intervention(s): Femoral alignment was measured prone. Hip-extension and abduction strength were obtained using a handheld dynamometer. Three-dimensional biomechanics and surface electromyography were obtained during single-leg forward landings. Main Outcome Measures: Forward stepwise multiple linear regressions determined the influence of femoral alignment on functional valgus collapse and the mediating effects of gluteus maximus and medius strength and activation. Results: In females, less hip abduction strength predicted greater peak hip adduction angle (R2 change = .10; P = .02), and greater hip-extensor activation predicted greater peak knee internal rotation angle (R2 change = .14; P = .01). In males, lesser hip abduction strength predicted smaller peak knee abduction moment (R2 change = .11; P = .03), and the combination of lesser hip abduction peak torque and lesser gluteus medius activation predicted greater hip internal rotation angle (R2 change = .15; P = .04). No meaningful mediation effects were observed (υadj < .01). Conclusions: In females, after accounting for femoral alignment, less gluteal strength and higher muscle activation were marginally associated with valgus movement. In males, less gluteal strength was associated with a more varus posture. Gluteal strength did not mediate femoral alignment. Future research should determine the capability of females to use their strength efficiently.

Computed Tomographic Evaluation of the Position of the Leg for Mortise Radiographs

2001 ◽  
Vol 22 (10) ◽  
pp. 828-831 ◽  
Author(s):  
Masato Takao ◽  
Mitsuo Ochi ◽  
Kohei Naito ◽  
Atsushi Iwata ◽  
Yuji Uchio ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Rotation Angle ◽  
Average Height ◽  
Computed Tomographic ◽  
Foot Length ◽  
Significant Difference ◽  
Tibiofibular Joint ◽  
Internal Rotation Angle ◽  
The Mean ◽  
Set Up

We investigated the most advantageous internal rotation angle of the leg for mortise radiographs. One hundred and twenty-eight feet of 64 healthy volunteers with no histories of ankle or foot pathology (72 feet of 36 males, 56 feet of 28 females) were examined. The subjects had an average age of 29 years (range, 19 to 51 years), average height of 167 cm (range, 157 to 181 cm), and average foot length of 25 cm (range, 23 to 27 cm). We obtained a plain axial view at the level of the central patella and 5 mm proximal to the tibial plafond using computed tomography, and investigated the inclination angle of the distal tibiofibular joint to a horizontal plane, regarding it as a mortise angle. The mean mortise angle was 19.1 + 5.0°. However, two peaks were observed at around 15° and 20°. This indicated that the mean mortise angle of the males was 21.2 + 4.6°, and the mean mortise angle of the females was 16.4 + 4.1°, with a significant difference between the males and the females' mortise angle (P < 0.0001). There was no correlation between the mortise angle and the height (P = 0.899 in the males, and P = 0.871 in the females), nor between the mortise angle and the foot length (P = 0.359 in the males, and P = 0.512 in the females). Therefore, we concluded that the internal rotation angle of the leg for mortise radiography should be generally set up at about 20° on males and 15° on females.

scholarly journals Use of a 3D Virtually Reconstructed Patient-Specific Model to Examine the Effect of Acetabular Labral Interference on Hip Range of Motion

2020 ◽  
Vol 8 (11) ◽  
pp. 232596712096446
Author(s):  
Shota Higashihira ◽  
Naomi Kobayashi ◽  
Hyonmin Choe ◽  
Kosuke Sumi ◽  
Yutaka Inaba
Keyword(s):  
Range Of Motion ◽  
Internal Rotation ◽  
Dynamic Simulation ◽  
Rotation Angle ◽  
Specific Model ◽  
Developmental Dysplasia ◽  
Patient Specific ◽  
Before And After ◽  
Internal Rotation Angle ◽  
Mri Scans

Background: The labrum is likely to influence impingement, which may also depend on acetabular coverage. Simulating impingement using 3-dimensional (3D) computed tomography (CT) is a potential solution to evaluating range of motion (ROM); however, it is based on bony structures rather than on soft tissue. Purpose: To examine ROM when the labrum is considered in a 3D dynamic simulation. A particular focus was evaluation of maximum flexion and internal rotation angles before occurrence of impingement, comparing them in cases of cam-type femoroacetabular impingement (FAI) and borderline developmental dysplasia of the hip (BDDH). Study Design: Descriptive laboratory study. Methods: Magnetic resonance imaging (MRI) and CT scans of 40 hips (20 with cam-type FAI and 20 with BDDH) were reviewed retrospectively. The thickness and width of the labrum were measured on MRI scans. A virtual labrum was reconstructed based on patient-specific sizes measured on MRI scans. The impingement point was identified using 3D dynamic simulation and was compared with the internal rotation angle before and after labral reconstruction. Results: The thickness and width of the labrum were significantly larger in BDDH than in FAI ( P < .001). In FAI, the maximum internal rotation angles without the labrum were 30.3° at 90° of flexion and 56.9° at 45° of flexion, with these values decreasing to 18.7° and 41.4°, respectively, after labral reconstruction ( P < .001). In BDDH, the maximum internal rotation angles were 48.0° at 90° of flexion and 76.7° at 45° of flexion without the labrum, decreasing to 31.1° and 55.3°, respectively, after labral reconstruction ( P < .001). The differences in the angles before and after labral reconstruction were larger in BDDH than in FAI (90° of flexion, P = .03; 45° of flexion, P = .01). Conclusion: As the labrum was significantly more hypertrophic in BDDH than in FAI, the virtual labral model revealed that the labrum’s interference with the maximum internal rotation angle was also significantly larger in BDDH. Clinical Relevance: The labrum has a significant effect on impingement; this is more significant for BDDH than for FAI.

Evaluation of an examination chair to quantify the hip internal rotation angle

2019 ◽  
Vol 30 (5) ◽  
pp. 581-586
Author(s):  
Bernd Friesenbichler ◽  
Nicola C Casartelli ◽  
Nicola A Maffiuletti ◽  
Michael Leunig
Keyword(s):  
Measurement Error ◽  
Internal Rotation ◽  
Measurement Errors ◽  
Rotation Angle ◽  
Hip Osteoarthritis ◽  
Observer Reliability ◽  
Future Assessment ◽  
Improve Measurement ◽  
Internal Rotation Angle ◽  
Hip Internal Rotation

Background:Deformities of the femoral head-neck junction are associated with limited hip internal rotation, which may lead to femoroacetabular impingement and consequently to hip osteoarthritis. This study compared inter- and intra-observer reproducibility of 3 different methods to quantify hip internal rotation.Methods:2 investigators assessed hip internal rotation of 30 asymptomatic participants during 2 separate testing sessions. Internal rotation was assessed by rotating the 90°-flexed hip manually while in a supine position (manual), in an examination chair capable of applying a single load (EC1) and in a newly developed examination chair with 5 load levels (EC2). Inter- and intra-observer reproducibility was compared among methods using reliability (intra-class correlation coefficient, ICC) and measurement error (smallest detectable chance).Results:Inter-observer reliability was good for the manual assessment (ICC = 0.83) and excellent for the EC1 and EC2 methods (ICC ⩾ 0.95) with expected measurement errors of 15.9°, 7.1° and 6.8°-14.3°, respectively. Intra-observer reliability was excellent for each method (ICC ⩾ 0.96), although measurement error ranged from 7.6°-11.8° for EC2 and was slightly higher compared to the manual (7.8°) and EC1 (5.9°) methods.Conclusions:Reproducibility of EC2 hip internal rotation angle assessment is superior to that of the manual assessment at specific load levels but not to the EC1 method. Future assessment devices need to incorporate a means of precisely producing and quantifying the loads applied to the hip joint in order to improve measurement reproducibility.

scholarly journals Association Between Hip Rotation and Activation of the Quadriceps and Gluteus Maximus in Male Runners

2020 ◽  
Vol 8 (11) ◽  
pp. 232596712096280
Author(s):  
Walaa S. Mohammad ◽  
Walaa M. Elsais
Keyword(s):  
Internal Rotation ◽  
Rotation Angle ◽  
Knee Injuries ◽  
Gluteus Maximus ◽  
Level Surface ◽  
Joint Injuries ◽  
Internal Rotation Angle ◽  
Recreational Runners ◽  
Hip Internal Rotation ◽  
Hip Rotation

Background: Although running can provide health benefits, knee joint injuries are frequently reported by recreational runners. To date, the precise mechanism responsible for anterior knee pain remains elusive, and the source of symptoms is debated. Inconsistencies are found in the literature pertaining to the relationship between hip mechanics and activity in the quadriceps and gluteus maximus (GMax) during the running gait. Purpose/Hypothesis: To investigate the correlations between hip rotation and the activity in the quadriceps and GMax during running. We hypothesized that increased hip rotation is correlated with decreased activity in these muscles. Study Design: Descriptive laboratory study. Methods: A cohort of 30 healthy recreational runners volunteered to participate in the study (mean ± SD age, 28.8 ± 5.66 years; height, 1.73 ± 0.05 m; mass, 69 ± 6.3 kg; body mass index, 23.02 ± 1.42 kg/m2). Surface electromyography (EMG) data were obtained from the GMax, vastus medialis obliquus (VMO), and vastus lateralis obliquus (VLO). These data were synchronized with a motion capture system during a level-surface running activity at a speed of 3.2 m/s. Results: A significantly strong, negative correlation was found between the hip internal rotation angle and EMG activity of the GMax and the VMO. However, the VLO showed a significant, moderate, and positive correlation of activity with the hip internal rotation angle. Conclusion: The present study showed that during level-surface running, decreased GMax activity may be the cause of distal joint injuries and alteration in quadriceps muscle activity. Clinical Relevance: Because GMax activity is important for controlling the lower body mechanics during running, evaluating GMax activity and internal hip rotation angle is important to prevent the running-related knee injuries that are linked to quadriceps deficits, such as patellofemoral pain. Additionally, clinicians and trainers should consider strengthening the GMax while rehabilitating running-related knee injuries.

scholarly journals Association Between Knee- and Hip-Extensor Strength and Running-Related Injury Biomechanics in Collegiate Distance Runners

2020 ◽  
Vol 55 (12) ◽  
pp. 1262-1269
Author(s):  
Tyler J. Moffit ◽  
Melissa M. Montgomery ◽  
Robert G. Lockie ◽  
Derek N. Pamukoff
Keyword(s):  
Internal Rotation ◽  
Knee Flexion ◽  
Rotation Angle ◽  
Distance Runners ◽  
Vertical Loading ◽  
Back Squat ◽  
Peak Knee ◽  
Internal Rotation Angle ◽  
Foot Strike ◽  
Running Biomechanics

Context Running-related injuries are common in distance runners. Strength training is used for performance enhancement and injury prevention. However, the association between maximal strength and distance-running biomechanics is unclear. Objective To determine the relationship between maximal knee- and hip-extensor strength and running biomechanics previously associated with injury risk. Design Cross-sectional study. Setting Research laboratory. Patients or Other Participants A total of 36 collegiate distance runners (26 men, 10 women; age = 20.0 ± 1.5 years, height = 1.74 ± 0.09 m, mass = 61.97 ± 8.26 kg). Main Outcome Measure(s) Strength was assessed using the 1-repetition maximum (1RM) back squat and maximal voluntary isometric contractions of the knee extensors and hip extensors. Three-dimensional running biomechanics were assessed overground at a self-selected speed. Running variables were the peak instantaneous vertical loading rate; peak forward trunk-lean angle; knee-flexion, internal-rotation, and -abduction angles and internal moments; and hip-extension, internal-rotation, and -adduction angles and internal moments. Separate stepwise linear regression models were used to examine the associations between strength and biomechanical outcomes (ΔR2) after accounting for sex, running speed, and foot-strike index. Results Greater 1RM back-squat strength was associated with a larger peak knee-flexion angle (ΔR2 = 0.110, ΔP = .045) and smaller peak knee internal-rotation angle (ΔR2 = 0.127, ΔP = .03) and internal-rotation moment (ΔR2 = 0.129, ΔP = .03) after accounting for sex, speed, and foot-strike index. No associations were found between 1RM back-squat strength and vertical loading rate, trunk lean, or hip kinematics and kinetics. Hip- and knee-extensor maximal voluntary isometric contractions were also not associated with any biomechanical variables. Conclusions Greater 1RM back-squat strength was weakly associated with a larger peak knee-flexion angle and smaller knee internal-rotation angle and moment in collegiate distance runners. Runners who are weaker in the back-squat exercise may exhibit running biomechanics associated with the development of knee-related injuries.

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