scholarly journals Kinetic and Kinematic Characteristics of Proficient and Non-Proficient 2-Point and 3-Point Basketball Shooters

Sports ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 2
Author(s):  
Dimitrije Cabarkapa ◽  
Andrew C. Fry ◽  
Damjana V. Cabarkapa ◽  
Chloe A. Myers ◽  
Grant T. Jones ◽  
...  
Keyword(s):  
Function Analysis ◽  
Force Plate ◽  
Elbow Flexion ◽  
Influential Factor ◽  
High Definition ◽  
Elbow Angle ◽  
Heel Height ◽  
Kinematic Characteristics ◽  
Preparatory Phase ◽  
Hip Flexion

The purpose of this study was to examine kinetic and kinematic characteristics of various types of 2-point and 3-point basketball shooting approaches and determine which variables have the greatest contribution in discriminating proficient (PRO) from non-proficient (N-PRO) shooters. While standing on a force plate, twenty-nine recreationally active males performed a total of 1740 shots by utilizing stationary and step-in shooting approaches. Two high-definition cameras were used to simultaneously capture kinematic parameters of shooting motions. The type of shooting approach showed as a non-influential factor. During the preparatory phase of the shooting motion, PRO 2-point shooters demonstrated higher elbow and basketball height placements, greater flexion in the shoulder and elbow joints while attaining greater release and entry ball angles during the release phase. PRO 3-point shooters demonstrated greater elbow flexion, higher basketball placement, and less hip flexion during the preparatory phase while attaining greater heel, release, and trajectory heights during the release phase. When entered into a full-model discriminant function analysis, elbow angle, elbow height, and release angle variables correctly classified PRO from N-PRO 2-point shooters in 62.1% of cases and hip angle, heel height, and elbow angle variables correctly classified PRO from N-PRO 3-point shooters in 81.6% of cases.

scholarly journals KINEMATIC DIFFERENCES BETWEEN PROFICIENT AND NON-PROFICIENT FREE THROW SHOOTERS – VIDEO ANALYSIS

2021 ◽  
Vol 1 (2021) ◽  
pp. 12-21
Author(s):  
Dimitrije Cabarkapa ◽  
◽  
Andrew C. Fry ◽  
John P. Poggio ◽  
Michael A. Deane ◽  
...  
Keyword(s):  
Video Analysis ◽  
Point Of View ◽  
High Definition ◽  
Projection Model ◽  
Free Throw ◽  
Margin Of Error ◽  
Preparatory Phase ◽  
Release Height ◽  
Hip Flexion ◽  
Shoulder Angle

Despite its importance and significant contribution to the final game outcome, the free throw shooting motion is greatly understudied. The purpose of this study was to examine kinematic differences between proficient and non-proficient free throw shooters and to determine which variables have the greatest impact on successful free throw shooting performance. Thirteen healthy recreationally active males volunteered to participate in this study. Each participant shot three sets of ten consecutive free throws from the regulation distance from the basket. Each set was performed under 3 minutes with 1-2-minute rest between each set. A high-definition camera recording at 30 fps captured the free throw shooting motion from a sagittal point of view. Video analysis software was used to analyze the following kinematic variables: knee angle, elbow angle, hip flexion, ankle flexion, release angle, shoulder angle, hand release height, and elbow height. The findings of this study suggest that lower elbow positioning influenced by greater knee, ankle, and hip flexion during the preparatory phase of the shooting motion may lead to improvements in free throw shooting accuracy. Moreover, greater ball release height and release angle, as previously suggested, could decrease the margin of error and enhance free throw shooting performance. By using these kinematic variables to create the discriminant function projection model, it is plausible that proficient free throw shooters can be accurately classified in 94% of cases.

scholarly journals Effect of Elbow Flexion Angle on Cortical Voluntary Activation of the Non-Impaired Biceps: A 3 Days Repeated Sessions Study

2020 ◽  
Author(s):  
Thibault Roumengous ◽  
Paul A. Howell ◽  
Carrie L. Peterson
Keyword(s):  
Cortical Neurons ◽  
Maximum Voluntary Contraction ◽  
Motor Evoked Potential ◽  
Elbow Flexion ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Elbow Angle ◽  
Flexion Extension ◽  
Minimal Stimulation ◽  
Stimulation Of

ABSTRACTMeasurement of cortical voluntary activation (VA) with transcranial magnetic stimulation (TMS) is limited by technical challenges. One challenge is the difficulty in preferential stimulation of cortical neurons projecting to the target muscle and minimal stimulation of cortical neurons projecting to antagonists. Thus, the motor evoked potential (MEP) response to TMS in the target muscle compared to its primary antagonist may be an important parameter in the assessment of cortical VA. Modulating isometric elbow angle alters the magnitude of MEPs at rest. The purpose of this study was to evaluate the effect of isometric elbow flexion-extension angle on: 1) the ratio of biceps MEP relative to the triceps MEP amplitude across a range of voluntary efforts, and 2) cortical VA. Ten non-impaired participants completed three sessions wherein VA was determined using TMS at 45°, 90° and 120° of isometric elbow flexion, and peripheral electrical stimulation at 90° of elbow flexion. The biceps/triceps MEP ratio was greater in the more flexed elbow angle (120° flexion) compared to 90° during contractions of 50% and 75% of maximum voluntary contraction. Cortical VA assessed in the more extended elbow angle (45° flexion) was lower relative to 90° elbow flexion; this effect was dependent on the biceps/triceps MEP ratio. Cortical VA was sensitive to small changes in the linearity of the voluntary torque and superimposed twitch relationship, regardless of the elbow angle. Peripheral and cortical VA measures at 90° of elbow flexion were repeatable across three days. In conclusion, although the biceps/triceps MEP ratio was increased at a more flexed elbow angle relative to 90°, there was not a corresponding difference in cortical VA. Thus, increasing the MEP ratio via elbow angle did not affect estimation of cortical VA.

Ankle and Midfoot Power During Single-Limb Heel Rise in Healthy Adults

2020 ◽  
Vol 36 (1) ◽  
pp. 52-55
Author(s):  
Frank E. DiLiberto ◽  
Deborah A. Nawoczenski
Keyword(s):  
Peak Power ◽  
Force Plate ◽  
Healthy Adults ◽  
Muscle Performance ◽  
Ground Reaction Forces ◽  
Inverse Dynamic ◽  
Heel Height ◽  
Foot Motion ◽  
Reaction Forces ◽  
Ankle Function

Although the midfoot is recognized to have an important role in the successful performance of a single-limb heel rise, healthy heel rise performance remains primarily characterized by ankle function. The purpose of this study was to examine the contribution of midfoot region power to single-limb heel rise in healthy adults. Participants (N = 12) performed 20 single-limb heel rises. An electromagnetic motion capture system and a force plate were used to record 3-segment foot motion and ground reaction forces. Inverse dynamic calculations were performed to obtain ankle and midfoot region powers. These data were evaluated with descriptive statistics. A correlation was performed to evaluate the contribution of midfoot region power to heel height, as heel height is a clinical measure of heel-rise performance. The midfoot contributed power during single-limb heel rise (peak positive power: 0.5 [0.2] W·kg−1). Furthermore, midfoot peak power accounted for 36% of the variance in heel height (P = .04). As energy generating internal mechanisms, such as muscle activity, are attributed to power generation, midfoot tissue loading and muscle performance should be considered during clinical and modeling applications of the heel-rise task.

scholarly journals The Effect of Prolonged Running on the Symmetry of Biomechanical Variables of the Lower Limb Joints

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 720
Author(s):  
Zixiang Gao ◽  
Qichang Mei ◽  
Gusztáv Fekete ◽  
Julien S Baker ◽  
Yaodong Gu
Keyword(s):  
Lower Limb ◽  
Force Plate ◽  
Knee Extension ◽  
Lower Limbs ◽  
Flexion Angle ◽  
Camera Motion ◽  
Long Distance ◽  
Therapy Assessment ◽  
Long Distance Running ◽  
Hip Flexion

The aim of this study was to examine whether there are kinematic and kinetic differences in the lower limb and whether the symmetry of the lower extremities is different after prolonged-running. Fifteen healthy male amateur runners (age: 22 ± 1 years, height: 173 ± 8 cm, mass: 65 ± 7 kg, BMI: 21.62 ± 2 kg/m2) were recruited as participants for this study. A Vicon eight-camera motion capture system and Kistler force plate were used to collect kinematic and kinetic parameters. A motorized treadmill, 15-point Borg scale and heart rate bands were used to monitor fatigue during a running-induced fatigue protocol. Paired sample T tests were used to check statistical difference (p = 0.05) between the lower limbs and the symmetry changes in pre-fatigue and post-fatigue running sessions. The symmetry angle (SA) of the knee flexion angle, hip flexion angle and hip extension angle in post-fatigue was significantly greater than in pre-fatigue, increasing by 4.32%, 10.71%, and 23.12%, respectively. Moreover, the SA of hip flexion moment increased by 2.61%. However, the knee extension velocity and hip flexion velocity became more symmetrical than in pre-fatigue (p < 0.05), the SA decreased by 5.91% and 5.45%, respectively. Differences in limb function during post-fatigue may lead to changes of symmetry in the lower limbs. The variables of asymmetry may be used as a compensation mechanism to maintain gait stability. Physical therapy assessment of fatigue injuries and long-distance running training programs may want to consider the changes in symmetry due to limb dominance.

scholarly journals Coordinated Ground Forces Exerted by Buttocks and Feet are Adequately Programmed for Weight Transfer During Sit-to-Stand

1999 ◽  
Vol 82 (6) ◽  
pp. 3021-3029 ◽  
Author(s):  
Helga Hirschfeld ◽  
Maria Thorsteinsdottir ◽  
Elisabeth Olsson
Keyword(s):  
Center Of Mass ◽  
Three Dimensional ◽  
The Body ◽  
Whole Body ◽  
Sit To Stand ◽  
Preparatory Phase ◽  
Base Distance ◽  
Left And Right ◽  
Hip Flexion ◽  
Weight Transfer

The purpose of this study was to test the hypothesis whether weight transfer during sit-to-stand (STS) is the result of coordinated ground forces exerted by buttocks and feet before seat-off. Whole-body kinematics and three-dimensional ground forces from left and right buttock as well as from left and right foot were recorded for seven adults during STS. We defined a preparatory phase from onset of the first detectable anterior/posterior (A/P) force to seat-off (buttock forces fell to 0) and a rising phase from seat-off to the decrease of center of mass (CoM) vertical velocity to zero. STS was induced by an increase of vertical and backward directed ground forces exerted by the buttocks that significantly preceded the onset of any trunk movement. All ground forces peaked before or around the moment of seat-off, whereas all kinematic variables, except trunk forward rotation and hip flexion, peaked after seat-off, during or after the rising phase. The present study suggests that the weight transfer from sit to stand is induced by ground forces exerted by buttocks and feet before seat-off, i.e., during the preparatory phase. The buttocks generate the isometric “rising forces,” e.g., the propulsive impulse for the forward acceleration of the body, while the feet apply adequate damping control before seat-off. This indicates that the rising movement is a result of these coordinated forces, targeted to match the subject's weight and support base distance between buttocks and feet. The single peaked, bell-shaped profiles peaking before seat-off, were seen beneath buttocks for the “rising drive,” i.e., between the time of peak backward directed force and seat-off, as well as beneath the feet for the “damping drive,” i.e., from onset to the peak of forward-directed force and for CoM A/P velocity. This suggests that both beginning and end of the weight transfer process are programmed before seat-off. The peak deceleration of A/P CoM took place shortly (∼100 ms) after CoM peak velocity, resulting in a well controlled CoM deceleration before seat-off. In contrast to the view of other authors, this suggests that body equilibrium is controlled during weight transfer.

scholarly journals Swimming and jumping in a semi-aquatic frog

2005 ◽  
Vol 55 (1) ◽  
pp. 3-15 ◽  
Author(s):  
Eize Stamhuis ◽  
Peter Aerts ◽  
Sandra Nauwelaerts
Keyword(s):  
Function Analysis ◽  
Swimming Performance ◽  
Force Plate ◽  
Rana Esculenta ◽  
Terrestrial Locomotion ◽  
Physical Environments ◽  
Image Velocimetry ◽  
Survival And Reproduction ◽  
Set Up ◽  
External Forces

AbstractLocomotion has a clear ecological relevance for many animals. As animals need to move in order to escape from predators, find food, defend territories, etc., it is expected that locomotor performance might affect an individual's survival and reproduction. Clear links have also been found between an animal's performance and its morphology. A function analysis can unravel the underlying mechanistic facets of this link.Frogs are interesting model species because they add an extra element to this topic; they have to perform in two entirely different physical environments, particularly semi-aquatic species. However, no trade-off was found between jumping and swimming performance. Morphological correlates were found but, to understand causations, a thorough understanding of the mechanics of locomotion is required.When comparing the mechanics of jumping and swimming, the question arises of how to ensure a sound comparison. Ideally, some measure of 'effort' has to be added to the analysis. We suggest the use of the propulsive impulse. Unexpectedly, the impulse of swimming proved to be significantly smaller than the jumping impulses during locomotion in a semi-aquatic frog, Rana esculenta, even when maximal performance had been induced in both media.To verify our impulse calculations, we analysed the external forces during both locomotor modes. The forces during terrestrial locomotion can be measured directly using a force plate; determining the forces in water requires a more complex set-up. For that reason, we performed a DPIV (Digital Particle Image Velocimetry) analysis on the flow generated by swimming frogs. These experiments confirmed the results of our impulse calculations.

scholarly journals Machinability Studies and Optimization of AA 6082/Fly Ash/Carbonized Eggshell Matrix Composite

2021 ◽  
Vol 31 (4) ◽  
pp. 207-216
Author(s):  
Ndudim H. Ononiwu ◽  
Chigbogu G. Ozoegwu ◽  
Nkosinathi Madushele ◽  
Esther T. Akinlabi
Keyword(s):  
Fly Ash ◽  
Function Analysis ◽  
Removal Rate ◽  
Desirability Function ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Chip Morphology ◽  
Influential Factor ◽  
Depth Of Cut ◽  
Desirability Function Analysis

Machinability studies of aluminium matrix composites (AMCs) is a necessary investigation required to understand their behaviour during machining to produce components effectively and efficiently. This established need has led to the investigation into the machinability of AA 6082 reinforced with 2.5 wt.% fly ash and 2.5 wt.% carbonized eggshell fabricated via stir casting. The studied machinability indices were material removal rate (MRR), cutting temperature, built-up edges (BUE) formation and chip morphology while the selected inputs were cutting speed (100 mm/min, 200 mm/min, 300 mm/min), feed (0.1 mm/rev, 0.2 mm/rev, 0.3 mm/rev) and depth of cut (0.5 mm, 1 mm, 1.5 mm). For the experimental design, the L9 orthogonal array was preferred to create 9 experimental runs. The analysis of the built-up edges showed that it increased at lower cutting speeds and increased feed and depth of cut. The examination of the produced chips after each experimental run showed the presence of c-shaped, helically shaped and ribbon-shaped chips. The analysis of variance (ANOVA) for both MRR and cutting temperature indicated that the depth of cut was the most influential factor on both responses. Multi-objective optimization using desirability function analysis showed that the optimum combination of parameters was 300 mm/min, 0.2 mm/rev and 1.0 mm for the cutting speed, feed and depth of cut respectively. The ANOVA of the composite desirability indicated that the cutting speed was the most contributing factor.

Running Mechanics and Metabolic Responses With Water Bottles and Bottle Belt Holders

2018 ◽  
Vol 13 (8) ◽  
pp. 977-985 ◽  
Author(s):  
Heather K. Vincent ◽  
Laura A. Zdziarski ◽  
Kyle Fallgatter ◽  
Giorgio Negron ◽  
Cong Chen ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Energy Use ◽  
Elbow Flexion ◽  
Water Bottle ◽  
3 Dimensional ◽  
Side Condition ◽  
Flexion Moment ◽  
The Right ◽  
Hip Flexion ◽  
Trained Runners

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.

scholarly journals Kinematic Strategies for Upper Arm–Forearm Coordination in Three Dimensions

2000 ◽  
Vol 84 (5) ◽  
pp. 2302-2316 ◽  
Author(s):  
W. P. Medendorp ◽  
J. D. Crawford ◽  
D.Y.P. Henriques ◽  
J.A.M. Van Gisbergen ◽  
C.C.A.M. Gielen
Keyword(s):  
Three Dimensional ◽  
Vertical Plane ◽  
Elbow Flexion ◽  
Three Dimensions ◽  
Upper Arm ◽  
Elbow Angle ◽  
Listing's Law ◽  
Listing’S Law ◽  
Governing Principle ◽  
The Cost

This study addressed the question of how the three-dimensional (3-D) control strategy for the upper arm depends on what the forearm is doing. Subjects were instructed to point a laser—attached in line with the upper arm—toward various visual targets, such that two-dimensional (2-D) pointing directions of the upper arm were held constant across different tasks. For each such task, subjects maintained one of several static upper arm–forearm configurations, i.e., each with a set elbow angle and forearm orientation. Upper arm, forearm, and eye orientations were measured with the use of 3-D search coils. The results confirmed that Donders' law (a behavioral restriction of 3-D orientation vectors to a 2-D “surface”) does not hold across all pointing tasks, i.e., for a given pointing target, upper arm torsion varied widely. However, for any one static elbow configuration, torsional variance was considerably reduced and was independent of previous arm position, resulting in a thin, Donders-like surface of orientation vectors. More importantly, the shape of this surface (which describes upper arm torsion as a function of its 2-D pointing direction) depended on both elbow angle and forearm orientation. For pointing with the arm fully extended or with the elbow flexed in the horizontal plane, a Listing's-law-like strategy was observed, minimizing shoulder rotations to and from center at the cost of position-dependent tilts in the forearm. In contrast, when the arm was bent in the vertical plane, the surface of best fit showed a Fick-like twist that increased continuously as a function of static elbow flexion, thereby reducing position-dependent tilts of the forearm with respect to gravity. In each case, the torsional variance from these surfaces remained constant, suggesting that Donders' law was obeyed equally well for each task condition. Further experiments established that these kinematic rules were independent of gaze direction and eye orientation, suggesting that Donders' law of the arm does not coordinate with Listing's law for the eye. These results revive the idea that Donders' law is an important governing principle for the control of arm movements but also suggest that its various forms may only be limited manifestations of a more general set of context-dependent kinematic rules. We propose that these rules are implemented by neural velocity commands arising as a function of initial arm orientation and desired pointing direction, calculated such that the torsional orientation of the upper arm is implicitly coordinated with desired forearm posture.

Accuracy of Visual Estimates of Joint Angle and Angular Velocity Using Criterion Movements

2005 ◽  
Vol 100 (3) ◽  
pp. 599-606 ◽  
Author(s):  
Craig S. Morrison ◽  
Colby Clayburn ◽  
Duane Knudson ◽  
Philip Haywood
Keyword(s):  
Angular Velocity ◽  
Joint Angle ◽  
Sagittal Plane ◽  
Elbow Flexion ◽  
Descriptive Study ◽  
Education Majors ◽  
Elbow Angle ◽  
Video Images ◽  
Physical Education Majors ◽  
True Peak

A descriptive study to document undergraduate physical education majors' (22.8 ± 2.4 yr. old) estimates of sagittal plane elbow angle and angular velocity of elbow flexion visually was performed. 42 subjects rated videotape replays of 30 movements organized into three speeds of movement and two criterion elbow angles. Video images of the movements were analyzed with Peak Motus™ to measure actual values of elbow angles and peak angular velocity. Of the subjects 85.7% had speed ratings significantly correlated with true peak elbow angular velocity in all three angular velocity conditions. Few (16.7%) subjects' ratings of elbow angle correlated significantly with actual angles. Analysis of the subjects with good ratings showed the accuracy of visual ratings was significantly related to speed, with decreasing accuracy for slower speeds of movement. The use of criterion movements did not improve the small percentage of novice observers who could accurately estimate body angles during movement.

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