OPTIMAL STANDING LONG JUMP SIMULATION FROM DIFFERENT STARTING POSTURES

2005 ◽  
Vol 05 (02) ◽  
pp. 203-215 ◽  
Author(s):  
KUANG-YOU B. CHENG ◽  
WEN-CHIEN CHEN
Keyword(s):  
Center Of Mass ◽  
Joint Torque ◽  
Horizontal Distance ◽  
Human Body Model ◽  
Body Model ◽  
Standing Long Jump ◽  
Jump Distance ◽  
Torque Generation ◽  
Long Jump ◽  
Simulation Results

A planar 4-segment human body model is used to simulate and study the effects of starting posture on standing long jumping performance. The model consists of frictionless hinge joints and is driven by joint torque actuators. The four segments represent feet, shanks, thighs, and trunk with head and arms. Movement simulations start from three different postures: high squat, squat, and low squat. The control variables are the joint torque activation levels and takeoff time. The objective function is the maximum horizontal distance from the toe point at takeoff to the center of mass (c.m.) position at landing. Optimal simulation results agree reasonably well with measurements. Different from previous high jump simulation study, slight dependence of initial posture on jump distance is found. Longer jump distance from a higher initial posture is probably due to greater range of countermovement that results in larger extension joint torque generation.

Phase-Specific Force and Time Predictors of Standing Long Jump Distance

2021 ◽  
pp. 1-8
Author(s):  
John R. Harry ◽  
John Krzyszkowski ◽  
Luke D. Chowning ◽  
Kristof Kipp
Keyword(s):  
National Collegiate Athletic Association ◽  
Reaction Force ◽  
Vertical Force ◽  
Jump Height ◽  
Strength Index ◽  
Phase Duration ◽  
Standing Long Jump ◽  
Jump Distance ◽  
Long Jump ◽  
Force Time

This study sought to identify potential predictors of standing long jump (SLJ) performance using force–time strategy metrics within the unloading, eccentric yielding, eccentric braking, and concentric phases. Fifteen National Collegiate Athletic Association division 1 male soccer players (19 [1] y, 1.81 [0.94] m, 80.3 [22.4] kg) performed 3 maximum-effort SLJs, while 3-dimensional ground reaction force (GRF) data were obtained. Regularized regression models were used to investigate associations between force–time strategy metrics and 2 metrics of SLJ performance (ie, jump distance and modified reactive strength index). Jump height and eccentric yielding time were the only predictors of jump distance that also demonstrated large correlations to jump distance. Anterior–posterior unloading yank, average concentric vertical force, and concentric phase duration were the only predictors of modified reactive strength index that also demonstrated large correlations to modified reactive strength index. To maximize SLJ distance in high-level soccer athletes, human performance practitioners could design interventions to drive changes in strategy to increase jump height and decrease eccentric yielding time. To improve SLJ explosiveness, interventions to drive changes in unloading and concentric force application and decrease concentric time could be emphasized. Importantly, unique variable combinations can be targeted when training for SLJ distance and explosiveness adaptations.

A New Method to Concentrate Electromagnetic Field Within ROI Using a High Dielectric Material in 3T Body MRI

2013 ◽  
Author(s):  
Bu S. Park ◽  
Sunder S. Rajan ◽  
Leonardo M. Angelone
Keyword(s):  
Numerical Simulation ◽  
Electromagnetic Field ◽  
Human Body ◽  
Region Of Interest ◽  
Dielectric Materials ◽  
The Body ◽  
Human Body Model ◽  
Body Model ◽  
Simulation Results ◽  
High Dielectric

We present numerical simulation results showing that high dielectric materials (HDMs) when placed between the human body model and the body coil significantly alter the electromagnetic field inside the body. The numerical simulation results show that the electromagnetic field (E, B, and SAR) within a region of interest (ROI) is concentrated (increased). In addition, the average electromagnetic fields decreased significantly outside the region of interest. The calculation results using a human body model and HDM of Barium Strontium Titanate (BST) show that the mean local SAR was decreased by about 56% (i.e., 18.7 vs. 8.2 W/kg) within the body model.

Is Increased Residual Shank Length a Competitive Advantage for Elite Transtibial Amputee Long Jumpers?

2011 ◽  
Vol 28 (3) ◽  
pp. 267-276 ◽  
Author(s):  
Lee Nolan ◽  
Benjamin L. Patritti ◽  
Laura Stana ◽  
Sean M. Tweedy
Keyword(s):  
Vertical Velocity ◽  
Important Determinant ◽  
Elite Athletes ◽  
Center Of Mass ◽  
Transtibial Amputation ◽  
Jump Performance ◽  
Performance Variables ◽  
Jump Distance ◽  
Long Jump ◽  
The Relationship

The purpose of this study was to evaluate the extent to which residual shank length affects long jump performance of elite athletes with a unilateral transtibial amputation. Sixteen elite, male, long jumpers with a transtibial amputation were videoed while competing in major championships (World Championships 1998, 2002 and Paralympic Games, 2004). The approach, take-off, and landing of each athlete’s best jump was digitized to determine residual and intact shank lengths, jump distance, and horizontal and vertical velocity of center of mass at touchdown. Residual shank length ranged from 15 cm to 38 cm. There were weak, nonsignificant relationships between residual shank length and (a) distance jumped (r = 0.30), (b) horizontal velocity (r = 0.31), and vertical velocity (r = 0.05). Based on these results, residual shank length is not an important determinant of long jump performance, and it is therefore appropriate that all long jumpers with transtibial amputation compete in the same class. The relationship between residual shank length and key performance variables was stronger among athletes that jumped off their prosthetic leg (N = 5), and although this result must be interpreted cautiously, it indicates the need for further research.

Development and Evaluation of a Close-Fitting Assistive Suit for Back and Arm Muscle – e.z.UP®–

2020 ◽  
Vol 32 (1) ◽  
pp. 157-172
Author(s):  
Yun-Ting Liao ◽  
Toshifumi Ishioka ◽  
Kazuko Mishima ◽  
Chiaki Kanda ◽  
Kenji Kodama ◽  
...  
Keyword(s):  
Human Body ◽  
Layer Structure ◽  
Human Body Model ◽  
Actuation Mechanism ◽  
Body Model ◽  
Additional Burden ◽  
Arm Muscles ◽  
Simulation Results ◽  
Young Subjects ◽  
Aged Subjects

This paper proposes a close-fitting assistive suit, called e.z.UP®, with a passive actuation mechanism composed of an adjustable structure. The suit can adequately assist the back and arm muscles of a user with the proposed layout of an arm assistive belt and a two-layer structure, respectively. With its lightweight characteristic (i.e., weighing 0.75 kg only), the proposed suit is portable and easy to wear without additional burden. By using the averaged Japanese body data, a simulation was conducted based on a human body model wearing our proposed suit to evaluate the layout of the arm assistive belt. The simulation results prove that the proposed suit can adequately assist the user’s arm muscles based on the user’s motion. An experiment involving the measurement of muscle activities is also implemented with seven young subjects and seven middle-aged subjects to evaluate the arm assistive belt and the two-layer structure. The experimental results reveal that the proposed suit can successfully and appropriately assist both the arm and back muscles simultaneously.

scholarly journals The adaptation to standing long jump distance in parkour is performed by the modulation of specific variables prior and during take-off

2017 ◽  
pp. 27-37
Author(s):  
Sidney Grosprêtre ◽  
Pierre Ufland ◽  
Daniel Jecker
Keyword(s):  
Center Of Pressure ◽  
Vertical Jump ◽  
Standing Long Jump ◽  
Jump Distance ◽  
Long Jump ◽  
Reaction Forces ◽  
Similar Distance ◽  
Force Time ◽  
Jump Trajectory ◽  
Curvilinear Trajectory

The present study aimed at investigating different variables that can be manipulated prior to and during take-off, to execute a specific standing long jump (SLJ) distance, according to jump expertise in parkour practitioners (= traceurs). Fourteen healthy young traceurs were included and separated into two groups: beginners (BEG) and experts (EXP). Firstly, classical vertical jump battery was used to characterize participants arm use and leg efficiency. Secondly, standing long jump (SLJ) performances were analyzed at four distances: 70, 80, 90, and 100% of each participant’s maximal SLJ distance. The force-time curves of the ground reaction forces (GRF) and the center of pressure (CoP) trajectory were measured with a force platform during the jump impulses. Take-off speed, angle and jump trajectory were estimated. For all of the participants, take-off speed and angle, power output, and vertical GRF during jump preparation (counter movement) varied with distance. The EXP group exhibited greater backward CoP excursion, greater arm participation, greater take-off velocity and a greater modulation of take-off angle than BEG group. When comparing jumps of similar distance, EXP exhibited a more curvilinear trajectory with a higher peak than BEG. To conclude, different motor strategies can be adopted based on the jump distance, and these strategies can evolve as parkour experience increases.

The Isometric Midthigh Pull in Basketball: An Effective Predictor of Sprint and Jump Performance in Male, Adolescent Players

2020 ◽  
Vol 15 (3) ◽  
pp. 409-415
Author(s):  
Aaron T. Scanlan ◽  
Neal Wen ◽  
Joshua H. Guy ◽  
Nathan Elsworthy ◽  
Michele Lastella ◽  
...  
Keyword(s):  
Peak Force ◽  
Male Adolescent ◽  
Basketball Players ◽  
Jump Performance ◽  
Sprint Time ◽  
Distance Correlation ◽  
Standing Long Jump ◽  
Jump Distance ◽  
Specific Performance ◽  
Long Jump

Purpose: To examine correlations between peak force and impulse measures attained during the isometric midthigh pull (IMTP) and basketball-specific sprint and jump tests. Methods: Male, adolescent basketball players (N = 24) completed a battery of basketball-specific performance tests. Testing consisted of the IMTP (absolute and normalized peak force and impulse at 100 and 250 ms); 20-m sprint (time across 5, 10, and 20 m); countermovement jump (CMJ; absolute and normalized peak force and jump height); standing long jump (distance); and repeated lateral bound (distance). Correlation and regression analyses were conducted between IMTP measures and other attributes. Results: An almost perfect correlation was evident between absolute peak force attained during the IMTP and CMJ (r = .94, R2 = 56%, P < .05). Moderate to very large correlations (P < .05) were observed between IMTP normalized peak force and 5-m sprint time (r = −.44, R2 = 19%), 10-m sprint time (r = −.45, R2 = 20%), absolute (r = .57, R2 = 33%), normalized (r = .86, R2 = 73%) CMJ peak force, and standing long-jump distance (r = .51, R2 = 26%). Moderate to very large correlations were evident between impulse measures during the IMTP and 5-m sprint time (100 ms, r = −.40, R2 = 16%, P > .05) and CMJ absolute peak force (100 ms, r = .73, R2 = 54%; 250 ms, r = .68, R2 = 47%; P < .05). Conclusions: The IMTP may be used to assess maximal and rapid force expression important across a range of basketball-specific movements.

scholarly journals Validity of field assessments to predict peak muscle power in preschoolers

2017 ◽  
Vol 42 (8) ◽  
pp. 850-854 ◽  
Author(s):  
Sara King-Dowling ◽  
Nicole A. Proudfoot ◽  
John Cairney ◽  
Brian W. Timmons
Keyword(s):  
Muscle Power ◽  
Linear Regression Analysis ◽  
Standing Long Jump ◽  
Jump Distance ◽  
Long Jump ◽  
Efficient Estimate ◽  
Run Time ◽  
Cost Efficient ◽  
Shuttle Run ◽  
Age And Sex

Field-based fitness assessments are time- and cost-efficient. However, no studies to date have reported the predictive value of field-based musculoskeletal fitness assessments in preschoolers. The purpose of this study was to determine the validity of 2 field assessments to predict peak muscle power in preschool-aged children. Four-hundred and nineteen 3- to 5-year olds participated (208 girls, 211 boys; mean age: 4.5 ± 0.9 years). Peak power (PP) was evaluated using a modified 10-s Wingate protocol as the criterion standard. Standing long-jump was measured in inches to the back of the heel using a 2-footed takeoff and landing. Shuttle-run time was measured using a shuttle-run protocol, which required children to sprint 50 feet (15.2 m), pick up a small block, and sprint back, with time measured to the closest tenth of a second. Regression modelling was used to calculate the predictive power of each field-based measurement, adjusting for weight (kg), age, and sex. Both standing long-jump distance and shuttle-run time were significantly correlated with PP (r = 0.636, p < 0.001, and r = –0.684, p < 0.001, respectively). Linear regression analysis determined that a child’s PP can be predicted from the child’s weight, age, and sex and either standing long-jump or shuttle-run time (adjusted R2 = 0.79, p < 0.001, and 0.81, p < 0.001, respectively). The standing long-jump and the Bruininks Oseretsky Test of Motor Proficiency 2nd Edition shuttle-run are both significant predictors of peak muscle power in preschool children. Either measure can be used as a cost- and time-efficient estimate of musculoskeletal fitness in preschoolers.

Kinematic Characteristics of the Standing Long Jump in Young Children Aged 4–5 Years

2021 ◽  
pp. 1-15
Author(s):  
Mana Ogawa ◽  
Chiaki Ohtaka ◽  
Motoko Fujiwara ◽  
Hiroki Nakata
Keyword(s):  
Young Children ◽  
Angular Displacement ◽  
Horizontal Direction ◽  
Movement Speed ◽  
Greater Trochanter ◽  
Kinematic Data ◽  
Kinematic Characteristics ◽  
Standing Long Jump ◽  
Jump Distance ◽  
Long Jump

The authors investigated the kinematic characteristics of the standing long jump in preschool children. Sixty 4-year-old children (boys: 30 and girls: 30) and sixty 5-year-old children (boys: 30 and girls: 30) participated in the present study. The authors focused on three differences in kinematics: between 4- and 5-year-old children, between boys and girls, and between high and low jumping performance groups at the same age. The kinematic data included the maximum flexions of the knee and hip before takeoff, at takeoff, and on landing; angular displacement of the upper body; takeoff speeds in horizontal and vertical directions; and takeoff angle of the greater trochanter. Anthropometric variables and kinematic data were separately analyzed with factors of age, sex, and group. The authors also performed multiple regression analysis to identify predictors of the jump distance. The movement speed of the greater trochanter in a horizontal direction, the maximum flexion angle of the hip before takeoff, and the hip angle on landing were identified as significant predictors of the jump distance among young children. These findings suggest that knowing how to use the hip and awareness of the horizontal direction are key factors to improve the long jump distance in young children.

Sign in / Sign up

Export Citation Format

Share Document