Pelvic Rotation Torque During Fast-Pitch Softball Hitting Under Three Ball Height Conditions

2014 ◽  
Vol 30 (4) ◽  
pp. 563-573 ◽  
Author(s):  
Yoichi Iino ◽  
Atsushi Fukushima ◽  
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.

2020 ◽  
Vol 8 (12) ◽  
pp. 232596712096629
Author(s):  
Caroline Martin ◽  
Anthony Sorel ◽  
Pierre Touzard ◽  
Benoit Bideau ◽  
Ronan Gaborit ◽  
...  

Background: The open stance forehand has been hypothesized by tennis experts (coaches, scientists, and clinicians) to be more traumatic than the neutral stance forehand as regards hip injuries in tennis. However, the influence of the forehand stance (open or neutral) on hip kinematics and loading has not been assessed. Purpose: To compare the kinematics and kinetics at the hip joint during 3 common forehand stances (attacking neutral stance [ANS], attacking open stance [AOS], defensive open stance [DOS]) in advanced tennis players to determine whether the open stance forehand induces higher hip loading. Study Design: Descriptive laboratory study. Methods: The ANS, AOS, and DOS forehand strokes of 8 advanced right-handed tennis players were recorded with an optoelectronic motion capture system. The flexion-extension, abduction-adduction, and external-internal rotation angles as well as intersegmental forces and torques of the right hip were calculated using inverse dynamics. Results: The DOS demonstrated significantly higher values than both the ANS and AOS for anterior ( P < .001), medial ( P < .001), and distractive ( P < .001) forces as well as extension ( P = .004), abduction ( P < .001), and external rotation ( P < .001) torques. The AOS showed higher distractive forces than the ANS ( P = .048). The DOS showed more extreme angles of hip flexion ( P < .001), abduction ( P < .001), and external rotation ( P = .010). Conclusion: The findings of this study imply that the DOS increased hip joint angles and loading, thus potentially increasing the risk of hip overuse injuries. The DOS-induced hip motion could put players at a higher risk of posterior-superior hip impingement compared with the ANS and AOS. Clinical Relevance: Coaches and clinicians with players who have experienced hip pain or sustained injuries should encourage them to use a more neutral stance and develop a more aggressive playing style to avoid the DOS, during which hip motion and loading are more extreme.


2012 ◽  
Vol 28 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Violaine Sevrez ◽  
Guillaume Rao ◽  
Eric Berton ◽  
Reinoud J. Bootsma

Five elite gymnasts performed giant circles on the high bar under different conditions of loading (without and with 6-kg loads attached to the shoulders, waist or ankles). Comparing the gymnasts’ kinematic pattern of movement with that of a triple-pendulum moving under the sole influence of nonmuscular forces revealed qualitative similarities, including the adoption of an arched position during the downswing and a piked position during the upswing. The structuring role of nonmuscular forces in the organization of movement was further reinforced by the results of an inverse dynamics analysis, assessing the contributions of gravitational, inertial and muscular components to the net joint torques. Adding loads at the level of the shoulders, waist or ankles systematically influenced movement kinematics and net joint torques. However, with the loads attached at the level of the shoulders or waist, the load-induced changes in gravitational and inertial torques provided the required increase in net joint torque, thereby allowing the muscular torques to remain unchanged. With the loads attached at the level of the ankles, this was no longer the case and the gymnasts increased the muscular torques at the shoulder and hip joints. Together, these results demonstrate that expert gymnasts skillfully exploit the operative nonmuscular forces, employing muscle force only in the capacity of complementary forces needed to perform the task.


1999 ◽  
Vol 23 (2) ◽  
pp. 152-162 ◽  
Author(s):  
P. M. Dall ◽  
B. Müller ◽  
I. Stallard ◽  
J. Edwards ◽  
M. H. Granat

Reciprocally linked orthoses used for paraplegic walking have some form of linkage between the two hip joints. It has been assumed that flexion of the swinging leg is driven by extension of the stance leg. The aims of this study were to investigate the moments generated around the hip joint by the two cables in a Louisiana State University Reciprocating Gait Orthosis (LSU-RGO). Six (6) subjects were recruited from the Regional Spinal Injuries Centre at Southport, who were experienced RGO users. The cables were fitted with strain gauged transducers to measure cable tension. Foot switches were used to divide the gait into swing and stance phases. A minimum of 20 steps were analysed for each subject. Moments about the hip joint for each phase of gait were calculated. There were no moments generated by the front cable in 4 of the subjects. In only 2 subjects did the cable generate a moment that could assist hip flexion during the swing phase. These moments were very low and at best could only have made a small contribution to limb flexion. The back cable generated moments that clearly prevented bilateral flexion. It was concluded that the front cable, as used by these experienced RGO users, did not aid flexion of the swinging limb.


2020 ◽  
Vol 10 (20) ◽  
pp. 7287
Author(s):  
Jihun Kim ◽  
Jaeha Yang ◽  
Seung Tae Yang ◽  
Yonghwan Oh ◽  
Giuk Lee

Although previous research has improved the energy efficiency of humanoid robots to increase mobility, no study has considered the offset between hip joints to this end. Here, we optimized the offsets of hip joints in humanoid robots via the Taguchi method to maximize energy efficiency. During optimization, the offsets between hip joints were selected as control factors, and the sum of the root-mean-square power consumption from three actuated hip joints was set as the objective function. We analyzed the power consumption of a humanoid robot model implemented in physics simulation software. As the Taguchi method was originally devised for robust optimization, we selected turning, forward, backward, and sideways walking motions as noise factors. Through two optimization stages, we obtained near-optimal results for the humanoid hip joint offsets. We validated the results by comparing the root-mean-square (RMS) power consumption of the original and optimized humanoid models, finding that the RMS power consumption was reduced by more than 25% in the target motions. We explored the reason for the reduction of power consumption through bio-inspired analysis from human gait mechanics. As the distance between the left and right hip joints in the frontal plane became narrower, the amplitude of the sway motion of the upper body was reduced. We found that the reduced sway motion of the upper body of the optimized joint configuration was effective in improving energy efficiency, similar to the influence of the pathway of the body’s center of gravity (COG) on human walking efficiency.


2021 ◽  
Vol 13 (2) ◽  
Author(s):  
Yujiang Xiang ◽  
Shadman Tahmid ◽  
Paul Owens ◽  
James Yang

Abstract Box delivery is a complicated task and it is challenging to predict the box delivery motion associated with the box weight, delivering speed, and location. This paper presents a single task-based inverse dynamics optimization method for determining the planar symmetric optimal box delivery motion (multi-task jobs). The design variables are cubic B-spline control points of joint angle profiles. The objective function is dynamic effort, i.e., the time integral of the square of all normalized joint torques. The optimization problem includes various constraints. Joint angle profiles are validated through experimental results using root-mean-square-error (RMSE) and Pearson’s correlation coefficient. This research provides a practical guidance to prevent injury risks in joint torque space for workers who lift and deliver heavy objects in their daily jobs.


Author(s):  
Yana V. Platonova ◽  
Valentina I. Syutina

Introduction. The statistics revealed during the literature analysis indicates the wide-spread of joint diseases worldwide, including hip diseases, and all human motor activity depends on the hip functioning. Limited mobility in the joint is caused by a sedentary lifestyle and the absence of movements with involved hip joint. The practice of conducting recreational aerobics classes with female students has shown the lack of girls’ proper attention to the mobility problem in the hip joints. Methods. 200 female students of 1–4 courses of Derzhavin Tambov State University, engaged in recreational aerobics, took part in the study of hip joint mobility. The study used tests to assess the degree of hip joint opening and to identify the presence of asymmetry when the legs are pulled to the sides. Results. There is a unidirectional tendency in the ability to perform motor action with the maximum amplitude of movement in the hip joints of female students of 1–4 courses. The thighs of the students open in the same way; there is no asymmetry between the right and left legs when opening. Conclusions. The study helped to draw up an overall balance and identify trends in the development of hip joint mobility in girls, to understand the causes leading to pelvic displacement and limited hip flexion amplitude, to expand the understanding of methods for assessing hip joint mobility and tests for detecting asymmetry when the legs are pulled to the sides.


2013 ◽  
Vol 29 (4) ◽  
pp. 428-434 ◽  
Author(s):  
Yoann Blache ◽  
Maarten Bobbert ◽  
Sebastien Argaud ◽  
Benoit Pairot de Fontenay ◽  
Karine M. Monteil

In experiments investigating vertical squat jumping, the HAT segment is typically defined as a line drawn from the hip to some point proximally on the upper body (eg, the neck, the acromion), and the hip joint as the angle between this line and the upper legs (θUL-HAT). In reality, the hip joint is the angle between the pelvis and the upper legs (θUL-pelvis). This study aimed to estimate to what extent hip joint definition affects hip joint work in maximal squat jumping. Moreover, the initial pelvic tilt was manipulated to maximize the difference in hip joint work as a function of hip joint definition. Twenty-two male athletes performed maximum effort squat jumps in three different initial pelvic tilt conditions: backward (pelvisB), neutral (pelvisN), and forward (pelvisF). Hip joint work was calculated by integrating the hip net joint torque with respect to θUL-HAT(WUL-HAT) or with respect to θUL-pelvis(WUL-pelvis). θUL-HATwas greater than θUL-pelvisin all conditions. WUL-HAToverestimated WUL-pelvisby 33%, 39%, and 49% in conditions pelvisF, pelvisN, and pelvisB, respectively. It was concluded that θUL-pelvisshould be measured when the mechanical output of hip extensor muscles is estimated.


2005 ◽  
Vol 99 (3) ◽  
pp. 1093-1103 ◽  
Author(s):  
Daichi Nozaki ◽  
Kimitaka Nakazawa ◽  
Masami Akai

In the single-joint torque exertion task, which has been widely used to control muscle activity, only the relevant joint torque is specified. However, the neglect of the neighboring joint could make the procedure unreliable, considering our previous result that even monoarticular muscle activity level is indefinite without specifying the adjacent joint torque. Here we examined the amount of hip joint torque generated with knee joint torque and its influence on the activity of the knee joint muscles. Twelve healthy subjects were requested to exert various levels of isometric knee joint torque. The knee and hip joint torques were obtained by using a custom-made device. Because no information about hip joint torque was provided to the subjects, the hip joint torque measured here was a secondary one associated with the task. The amount of hip joint torque varied among subjects, indicating that they adopted various strategies to achieve the task. In some subjects, there was a considerable internal variability in the hip joint torque. Such variability was not negligible, because the knee joint muscle activity level with respect to the knee joint torque, as quantified by surface electromyography (EMG), changed significantly when the subjects were requested to change the strategy. This change occurred in a very systematic manner: in the case of the knee extension, as the hip flexion torque was larger, the activity of mono- and biarticular knee extensors decreased and increased, respectively. These results indicate that the conventional single knee joint torque exertion has the drawback that the intersubject and/or intertrial variability is inevitable in the relative contribution among mono- and biarticular muscles because of the uncertainty of the hip joint torque. We discuss that the viewpoint that both joint torques need to be considered will bring insights into various controversial problems such as the shape of the EMG-force relationship, neural factors that help determine the effect of muscle strength training, and so on.


2010 ◽  
Vol 23 (01) ◽  
pp. 19-27 ◽  
Author(s):  
A. Volta ◽  
J. P. Morgan ◽  
M. Bonazzi ◽  
S. Manfredi ◽  
E. Bottarelli ◽  
...  

Summary Objectives: To evaluate distinctive features of pelvis and hip joint development of English Bulldogs throughout the first year of life. Methods: The pelves of 20 English Bulldogs were radiographed at three different ages (<4, 6–8, and 12–14 months). At each time point, the dogs were clinically evaluated and the abnormal hip joints were classified as mild, moderate, or severely deformed. The pelves were compared to a phantom study in which external rotation of a normal hemipelvis around its long axis was artificially created at different degrees, with different pelvic inclinations, and classified as either normal and without deformity, or as mild, moderate, or severely deformed. Hip joints and pelvic scores were statistically compared. Results: Although none of the dogs were considered lame at the end of the study, none of the hips showed normal development; 77.5% were moderately to severely deformed at 12–14 months of age. At this age, 75% of the hemipelves had moderate to severe torsional deformity (>5.2° of external rotation), with retroversion of the acetabulum confirmed by the presence of the crossover sign. An external rotation of the hemipelvis on its long axis >5° was likely associated with a moderate to severely altered hip joint conformation. Clinical Significance: Abnormal hip conformation was common in this series of English Bulldogs. Torsional deformity of the pelves with acetabular retroversion was a common and distinctive feature, which has not yet been thoroughly studied in dogs. These findings need further evaluation in English Bulldogs as well as in other breeds.


2013 ◽  
Vol 378 ◽  
pp. 382-386
Author(s):  
Hai Bin Liu ◽  
Zhi Qiang He ◽  
Wen Xue Yuan ◽  
Zhao Li Meng

Objective: Research on ankle joint torques of healthy women with high heel compared with bare foot based on Inverse Dynamics. Methods: 12 women were recruited and tested by motion and force system. Kinematical, kinetic and personal segment parameter data were used to compute ankle joint torques and compare the differences between bare foot and high heel.Conclusion: compared with bare foot, It can infer that Soleus and Gastrocnemius access the contraction in advance and keep higher muscle force. Tibia Anterior and Posterior must have to make powerful contraction that could keep the ankle joint with higher torque. Compared with sagital and frontal plane, high heel doesnt change the joint torque in horizontal plane during the whole internal phase, but the fluctuations of torque value may influence the stability during normal level walking.


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