processing. The marker coordinates were used to construct local orthonormal reference frames per segment to calculate segment angles (pelvis and trunk) and joint angles (shoulder, elbow, and wrist) based on the International Society of Biomechanics (ISB) guidelines for construction of reference frames and
Ben Serrien, Maggy Goossens, and Jean-Pierre Baeyens
M. A. Urbin, David Stodden, and Glenn Fleisig
Individual body segment actions evolve during throwing skill development. Maximal trunk involvement is typically the last feature of the movement pattern to fully develop. The current study examined developmental levels of trunk action and the associated variability in the throwing motion. The throwing motions of children and adolescents were analyzed via motion capture and trunk actions were classified as exhibiting no rotation (n = 7), blocked rotation (n = 6), or differentiated rotation (n = 11). Results indicated nonrotators exhibited greater variability than blocked-rotators in maximum humeral external rotation and humeral horizontal adduction angles at ball release; nonrotators also demonstrated greater variability than differentiated-rotators on these parameters, in addition to forward trunk tilt and elbow extension angle at ball release. Nonrotators produced more variable peak upper torso and humeral horizontal adduction angular velocities, as well as peak upper torso linear velocity, relative to differentiated-rotators. Blocked-rotators produced more variable peak pelvis, upper torso, and humeral horizontal adduction angular velocities, as well peak pelvis linear velocity, relative to differentiated-rotators. Nonrotators were less consistent relative to blocked- and differentiated-rotators in the time that elapsed from peak pelvis angular velocity to ball release. These results indicate that greater trunk involvement is associated with more consistent movement production.
Jongseong An, Gabriele Wulf, and Seonjin Kim
We examined the effects of attentional focus instructions on the learning of movement form and carry distance in low-skilled golfers. The X-factor describes the rotation of the shoulders relative to the pelvis, and its increase during the downswing (so-called X-factor stretch) is associated with the carry distance of the ball. X-factor stretch and carry distance have been shown to be associated with an early weight shift toward the front leg during the downswing. In our study, one group (internal focus, IF) was instructed to focus on shifting their weight to their left foot while hitting the ball, whereas another group (external focus, EF) was instructed to focus on pushing against the left side of the ground. A control (C) group was not given attentional focus instructions. Participants performed 100 practice trials. Learning was assessed after a 3-day interval in a retention test without focus instructions. The EF group demonstrated a greater carry distance, X-factor stretch, and higher maximum angular velocities of the pelvis, shoulder, and wrist than both the IF and C groups, which showed very similar performances. These findings demonstrate that both movement outcome and form can be enhanced in complex skill learning by providing the learner with an appropriate external focus instruction. Moreover, they show that a single external focus cue can be sufficient to elicit an effective whole-body coordination pattern.
Jianwei Duan, Kuan Wang, Tongbo Chang, Lejun Wang, Shengnian Zhang, and Wenxin Niu
0.625-mm slice thickness. Scanning range includes the fifth lumbar vertebrae, intervertebral disc, whole pelvis, and the two proximal femurs in the standard supine position. The image data were imported into Mimics (version 17.0; Materialise, Leuven, Belgium) for segmentation and reconstruction
Rose M. Angell, Stephen A. Butterfield, Shihfen Tu, E. Michael Loovis, Craig A. Mason, and Christopher J. Nightingale
Object control skills (OCS) provide children the means to be physically active. However, gender equality in some OCS remains elusive. Particularly troublesome is the basic throwing pattern and, by extension, the striking pattern, both of which rely on forceful, rapid rotation of the pelvis, trunk, and shoulders. Some scholars argue that sex differences in throwing and striking are rooted in human evolution. The purpose of this study was to examine development of throwing and striking at the fundamental movement level. The design was multi-cohort sequential: 280 boys and girls grades K–8 (ages 4–15) were tested up to three times per year for 5 years on the Test of Gross Motor Development (TGMD-2). Hierarchical linear modeling (HLM) was applied to analyze individual growth curves. As anticipated, significant (p < .001) age-related gains were found for throwing and striking. In terms of sex (biology) or gender (sociocultural) differences, boys performed better longitudinally at throwing (p < .05) and striking (p < .05). These results reinforce theories that girls may be disadvantaged in achieving proficiency in throwing and striking. Interventions designed to enhance development of these skills should be in place long before grade 4, when most physical education curricula transitions to games and sports.
Anson B. Rosenfeldt, Amanda L. Penko, Andrew S. Bazyk, Matthew C. Streicher, Tanujit Dey, and Jay L. Alberts
self-paced treadmill surrounded by a 180° projection screen allows an individual to be immersed in an activity or scene. A self-paced treadmill speed algorithm ( Sloot, van der Krogt, & Harlaar, 2014 ) incorporating anterior–posterior pelvis position relative to the center of the treadmill to control
Caterina Pesce, Ilaria Masci, Rosalba Marchetti, Giuseppe Vannozzi, and Mirko Schmidt
association was inverse, because the lower the aP ML , the better the running performance. As regards throwing, two parameters were directly and inversely associated with perceived competence, respectively: range of motion of yaw calculated during the cocking phase (ROM Yaw ) and the maximum pelvis vertical
Danielle Nesbitt, Sergio Molina, Ryan Sacko, Leah E. Robinson, Ali Brian, and David Stodden
Categories for Task of Rising from a Supine to a Standing Position (Adapted from Marsala & VanSant, 1998 ; Vansant, 1988a , 1988b ) Upper Extremity Movement Patterns Level 1 Push and reach to bilateral push. One hand is placed on the support surface beside the pelvis. The other arm reaches across the
Jerraco L. Johnson, Mary E. Rudisill, Peter A. Hastie, and Julia Sassi
trunk action occurs, it accompanies the forward thrust of the arm by flexing forward at the hips. Preparatory extension sometimes precedes forward hip flexion. Step 2 Upper trunk rotation or total trunk (“block”) rotation. The spine and pelvis rotate away from the intended line of flight and then
Nathaniel S. Nye, Drew S. Kafer, Cara Olsen, David H. Carnahan, and Paul F. Crawford
lower extremity, pelvis/spine, or upper extremity during this period. Those with nonmusculoskeletal injuries, such as concussions or skin lacerations, were not excluded. Furthermore, those with a documented diagnosis of any one or more possible confounding conditions were completely excluded from the