Search Results

You are looking at 1 - 10 of 32 items for :

  • "pelvic rotation" x
  • Refine by Access: All Content x
Clear All
Restricted access

Yoichi Iino, Atsushi Fukushima, and Takeji Kojima

The purpose of this study was to investigate the relevance of hip joint angles to the production of the pelvic rotation torque in fast-pitch softball hitting and to examine the effect of ball height on this production. Thirteen advanced female softball players hit stationary balls at three different heights: high, middle, and low. The pelvic rotation torque, defined as the torque acting on the pelvis through the hip joints about the pelvic superior–inferior axis, was determined from the kinematic and force plate data using inverse dynamics. Irrespective of the ball heights, the rear hip extension, rear hip external rotation, front hip adduction, and front hip flexion torques contributed to the production of pelvic rotation torque. Although the contributions of the adduction and external rotation torques at each hip joint were significantly different among the ball heights, the contributions of the front and rear hip joint torques were similar among the three ball heights owing to cancelation of the two torque components. The timings of the peaks of the hip joint torque components were significantly different, suggesting that softball hitters may need to adjust the timings of the torque exertions fairly precisely to rotate the upper body effectively.

Restricted access

Soo-Yong Kim, Jae-Seop Oh, and Min-Hyeok Kang

asymmetrically, then rotation may occur, disrupting the neutral position of the lumbopelvic region. Subsequently, pelvic rotation torque may produce bilateral activity of the trunk or asymmetry of the hip extensors. 7 , 8 Additionally, the repeated performance of bridge exercises using the sling in the absence

Restricted access

Aiko Sakurai, Kengo Harato, Yutaro Morishige, Shu Kobayashi, Yasuo Niki, and Takeo Nagura

anterior inclination, deg 18.9 (10.0) 16.4 (9.9)* 14.2 (10.6)** , *** <.001 Pelvic inclination toward the nonlanding side, deg 7.4 (9.4) 0.3 (5.1)* −4.6 (4.1)** , *** <.001 Pelvic rotation toward the nonlanding side, deg 29.7 (8.5) 11.7 (7.7)* −1.6 (9.2)** , *** <.001 Trunk anterior inclination, deg 25

Restricted access

Matt Greig

calculated. The orientation of the pelvis relative to the frontal plane was also quantified for each stage, given the contribution of pelvic rotation to kicking performance. 15 , 21 Coordinate data of the anterior superior iliac spine, posterior superior iliac spine, and each greater trochanter were used to

Restricted access

Christian A. Clermont, Lauren C. Benson, W. Brent Edwards, Blayne A. Hettinga, and Reed Ferber

) bounce (vertical oscillation, in centimeters); (4) pelvic rotation (side-to-side movement of the pelvis, in degrees); (5) pelvic drop (side-to-side drop of the pelvis, in degrees); and (6) ground contact time (time foot is in contact with the ground at each step, in milliseconds). The Lumo Run® variables

Restricted access

Richard W. Bohannon and Jason Smutnick

Motion of the femur and pelvis during hip flexion has been examined previously, but principally in the sagittal plane and during nonfunctional activities. In this study we examined femoral elevation in the sagittal plane and pelvic rotation in the sagittal and frontal planes while subjects flexed their hips to ascend single steps. Fourteen subjects ascended single steps of 4 different heights leading with each lower limb. Motion of the lead femur and pelvis during the flexion phase of step ascent was tracked using an infrared motion capture system. Depending on step height and lead limb, step ascent involved elevation of the femur (mean 47.2° to 89.6°) and rotation of the pelvis in both the sagittal plane (tilting: mean 2.6° to 9.7°) and frontal plane (listing: mean 4.2° to 11.9°). Along with maximum femoral elevation, maximum pelvic rotation increased significantly (p < .001) with step height. Femoral elevation and pelvic rotation during the flexion phase of step ascent were synergistic (r = .852–.999). Practitioners should consider pelvic rotation in addition to femoral motion when observing individuals’ ascent of steps.

Restricted access

David W. Meister, Amy L. Ladd, Erin E. Butler, Betty Zhao, Andrew P. Rogers, Conrad J. Ray, and Jessica Rose

The purpose of this study was to determine biomechanical factors that may influence golf swing power generation. Three-dimensional kinematics and kinetics were examined in 10 professional and 5 amateur male golfers. Upper-torso rotation, pelvic rotation, X-factor (relative hip-shoulder rotation), O-factor (pelvic obliquity), S-factor (shoulder obliquity), and normalized free moment were assessed in relation to clubhead speed at impact (CSI). Among professional golfers, results revealed that peak free moment per kilogram, peak X-factor, and peak S-factor were highly consistent, with coefficients of variation of 6.8%, 7.4%, and 8.4%, respectively. Downswing was initiated by reversal of pelvic rotation, followed by reversal of upper-torso rotation. Peak X-factor preceded peak free moment in all swings for all golfers, and occurred during initial downswing. Peak free moment per kilogram, X-factor at impact, peak X-factor, and peak upper-torso rotation were highly correlated to CSI (median correlation coefficients of 0.943, 0.943, 0.900, and 0.900, respectively). Benchmark curves revealed kinematic and kinetic temporal and spatial differences of amateurs compared with professional golfers. For amateurs, the number of factors that fell outside 1–2 standard deviations of professional means increased with handicap. This study identified biomechanical factors highly correlated to golf swing power generation and may provide a basis for strategic training and injury prevention.

Restricted access

Leo Ng, Amity Campbell, Angus Burnett, and Peter O’Sullivan

The trunk and pelvis kinematics of 20 healthy male and female adolescent rowers were recorded during an ergometer trial using an electromagnetic tracking system (Fastrak). The kinematics of each drive phase were collected during the 1st and 20th minute, respectively. The mean and range of the kinematics, stroke rate and stroke length were compared between genders and over time. Male rowers postured their pelvis with more posterior tilt and their thoracic spine in more flexion than female rowers (P < .05). Both genders postured their pelvis in more posterior pelvic rotation and upper trunk in more flexion over time. Male rowers were found to have a significantly shorter drive phase than female rowers (P = .001). Differences in trunk and pelvic kinematics between adolescent male and female rowers suggest potentially various mechanisms for biomechanical stress. Assessment and training of rowers should take gender differences into consideration.

Restricted access

Katherine A. Boyer, Julia Freedman Silvernail, and Joseph Hamill

Injury rates among runners are high, with the knee injured most frequently. The interaction of running experience and running mechanics is not well understood but may be important for understanding relative injury risk in low vs higher mileage runners. The study aim was to apply a principal component analysis (PCA) to test the hypothesis that differences exist in kinematic waveforms and coordination between higher and low mileage groups. Gait data were collected for 50 subjects running at 3.5 m/s assigned to either a low (< 15 miles/wk) or higher (> 20 miles/wk, 1 year experience) mileage group. A PCA was performed on a matrix of trial vectors of all force, joint kinematic, and center of pressure data. The projection of the subjects’ trial vectors onto the linear combination of PC7, PC10, PC13, and PC19 was significantly different between the higher and lower mileage groups (d = 0.63, P = .012). This resultant PC represented variation in transverse plane pelvic rotation, hip internal rotation, and hip and knee abduction and adduction angles. These results suggest the coordination of lower extremity segment kinematics is different for lower and higher mileage runners. The adopted patterns of coordinated motion may explain the lower incidence of overuse knee injuries for higher mileage runners.

Restricted access

Heather K. Vincent, Laura A. Zdziarski, Kyle Fallgatter, Giorgio Negron, Cong Chen, Trevor Leavitt, MaryBeth Horodyski, Joseph G. Wasser, and Kevin R. Vincent

Purpose: To determine whether differential kinematics, kinetics, rates of energy use, and cardiopulmonary responses occur during running with water bottles and bottle belt holders compared with running only. Methods: Trained runners (N = 42; age 27.2 [6.4] y) ran on an instrumented treadmill for 4 conditions in a randomized order: control run (CON), handheld full water bottle (FULL; 16.9 fluid oz; 454 g), handheld half-full water bottle (HALF; 8.4 fluid oz; 227 g), and waist-worn bottle belt holder (BELT; hydration belt; 676 g). Gas exchange was measured using a portable gas analyzer. Kinetic and kinematic responses were determined by standard 3-dimensional videographic techniques. Interactions of limb side (right and left) by study condition (CON, FULL, HALF, and BELT) were tested for rates of oxygen use and energy expenditure and kinematic and kinetic parameters. Results: No significant limb-side × condition interactions existed for rates of oxygen use or energy expenditure. A significant interaction occurred with sagittal elbow flexion (P < .001). Transverse pelvic-rotation excursions differed on average 3.8° across conditions. The minimum sagittal hip-flexion moment was higher in the right leg in the HALF and BELT conditions compared with CON (P < .001). Conclusions: Carrying water by hand or on the waist does not significantly change the kinematics of running motion, rates of oxygen use and energy expenditure, or cardiopulmonary measures over short durations. Runners likely make adjustments to joint moments and powers that preserve balance and protect the lower-extremity joints while maintaining rates of oxygen use and energy expenditure.