scholarly journals Effect of Landing Posture on Jump Height Calculated from Flight Time

2020 ◽  
Vol 10 (3) ◽  
pp. 776 ◽  
Author(s):  
Daichi Yamashita ◽  
Munenori Murata ◽  
Yuki Inaba
Keyword(s):  
Vertical Velocity ◽  
Vertical Jump ◽  
Center Of Mass ◽  
Reaction Force ◽  
Three Dimensional ◽  
Flight Time ◽  
Whole Body ◽  
Anatomical Landmarks ◽  
Jump Height ◽  
Postural Changes

Flight time is widely used to calculate jump height because of its simple and inexpensive application. However, this method is known to give different results than the calculation from vertical velocity at takeoff. The purpose of this study is to quantify the effect of postural changes between takeoff and landing on the jump height from flight time. Twenty-seven participants performed three vertical jumps with arm swing. Three-dimensional coordinates of anatomical landmarks and the ground reaction force were analyzed. Two methods of calculating jump height were used: (1) the vertical velocity of the whole-body center of mass (COMwb) at takeoff and (2) flight time. The jump height from flight time was overestimated by 0.025 m compared to the jump height from the takeoff velocity (p < 0.05) due to the lower COMwb height at landing by −0.053 m (p < 0.05). The postural changes in foot, shank, and arm segments mainly contributed to decreasing the COMwb height (−0.025, −0.014, and −0.017 m, respectively). The flight time method is reliable and had low intra-participant variability, but it cannot be recommended for a vertical jump when comparing with others (such as at tryouts) because of the potential “cheating” effect of differences in landing posture.

Pelvic Kinematic Method for Determining Vertical Jump Height

2010 ◽  
Vol 26 (4) ◽  
pp. 508-511 ◽  
Author(s):  
Loren Z.F. Chiu ◽  
George J. Salem
Keyword(s):  
Vertical Jump ◽  
Center Of Mass ◽  
Reaction Force ◽  
Jump Height ◽  
Impulse Method ◽  
Vertical Jump Height ◽  
Reconstruction Methods ◽  
Kinematic Method ◽  
Mass Displacement ◽  
Vertical Jumps

Sacral marker and pelvis reconstruction methods have been proposed to approximate total body center of mass during relatively low intensity gait and hopping tasks, but not during a maximum effort vertical jumping task. In this study, center of mass displacement was calculated using the pelvic kinematic method and compared with center of mass displacement using the ground-reaction force-impulse method, in experienced athletes (n= 13) performing restricted countermovement vertical jumps. Maximal vertical jumps were performed in a biomechanics laboratory, with data collected using an 8-camera motion analysis system and two force platforms. The pelvis center of mass was reconstructed from retro-reflective markers placed on the pelvis. Jump height was determined from the peak height of the pelvis center of mass minus the standing height. Strong linear relationships were observed between the pelvic kinematic and impulse methods (R2= .86;p< .01). The pelvic kinematic method underestimated jump height versus the impulse method, however, the difference was small (CV = 4.34%). This investigation demonstrates concurrent validity for the pelvic kinematic method to determine vertical jump height.

scholarly journals Correlation and Reliability of Two Field Tests for Vertical Jump Height

2020 ◽  
Vol 22 (1) ◽  
pp. 9-14 ◽  
Author(s):  
YongSuk Lee ◽  
Kyeong Eun Min ◽  
Jihong Park
Keyword(s):  
High Reliability ◽  
Pearson Correlation ◽  
Vertical Jump ◽  
Intraclass Correlation ◽  
Field Tests ◽  
Flight Time ◽  
Whole Body ◽  
Jump Height ◽  
Vertical Jump Height ◽  
Highly Correlated

OBJECTIVES This study established the relationship and reliability of vertical jump height measurements using both the jump-reach method and the flight-time method.METHODS Sixteen healthy subjects (13 males and 3 females, body mass index: 22.5 kg/m<sup>2</sup>) visited the laboratory twice with at least two days between visits. During each visit, they performed three successful trials of one- and two-legged maximal vertical jumps on a Vertec jump tester (the jump-reach method). Simultaneously, two digital cameras were videotaped, one for a whole body view and another for a view of the feet (240 frame rate and 1/1000 s shutter speed). Flight-times were measured using a free motion analysis software (Kinovea 0.8.15) and were then inserted into the formula h = t<sup>2 </sup>× 122.625 to calculate the height. To determine if the jump values from each method were correlated, average values from the three trials for both jump methods were analyzed using Pearson correlation and simple linear regression tests. To establish a within- and between-session reliability, the intraclass correlation coefficients (ICCs) were calculated.RESULTS Assessed vertical jump heights using the two methods were highly correlated with each other (r values ranged between 0.86 and 0.93 with p<0.0001 for all tests) and showed high reliability (ICC values ranged between 0.73 and 0.99 for all tests).CONCLUSIONS Vertical jump heights assessed by the two field tests were highly correlated and consistent. Although the flight-time method calculates less jump heights, the underestimated amount can be estimated by the established equations. We suggest that athletes and coaches use either technique in the field in consideration of advantages for each method.

scholarly journals Effects of Plyometric vs. Combined Plyometric Training on Vertical Jump Biomechanics in Female Basketball Players

2021 ◽  
Vol 77 (1) ◽  
pp. 25-35
Author(s):  
Alberto Sánchez-Sixto ◽  
Andrew J Harrison ◽  
Pablo Floría
Keyword(s):  
Vertical Velocity ◽  
Vertical Jump ◽  
Center Of Mass ◽  
Height Velocity ◽  
Moderate Increase ◽  
Training Methods ◽  
Plyometric Training ◽  
Basketball Players ◽  
Jump Performance ◽  
Combined Training

Abstract The purpose of this study was to assess and compare the effects of plyometric training and combined training programs on vertical jump kinematics and kinetics of female basketball players. Thirty-six female basketball players were included in the study and further divided into three groups: plyometric training, n = 11; combined training n =13; and a control group, n =12. Combined training comprised full squat exercise with low resistance (50-65% 1RM) and low volume (3-6 repetitions/set) combined with repeated jumps. Plyometric training included drop jumps and repeated jumps. Both training methods showed a moderate increase in jump performance, although combined training achieved substantially higher values than plyometric training alone. After plyometric training, the vertical velocity and displacement of the center of mass of the countermovement jump increased, while force variables decreased. Combined training increased power, vertical velocity and displacement of the center of mass, but force variables remained unchanged. Both training methods improved jump height, velocity and displacement of the center of mass. Combined training maintained force measures while plyometric training decreased them. These results indicate that combined training might provide better outcomes on jump performance than plyometric training alone. It also appears important to measure biomechanical variables to appropriately interpret the effects of different training methods.

scholarly journals Effect of Leg Dominance on The Center-of-Mass Kinematics During an Inside-of-the-Foot Kick in Amateur Soccer Players

2014 ◽  
Vol 42 (1) ◽  
pp. 51-61 ◽  
Author(s):  
Matteo Zago ◽  
Andrea Francesco Motta ◽  
Andrea Mapelli ◽  
Isabella Annoni ◽  
Christel Galvani ◽  
...  
Keyword(s):  
Body Movement ◽  
Center Of Mass ◽  
Three Dimensional ◽  
The Body ◽  
Soccer Players ◽  
Upper Body ◽  
Whole Body ◽  
Movement Velocity ◽  
Ground Support ◽  
Analysis System

Abstract Soccer kicking kinematics has received wide interest in literature. However, while the instep-kick has been broadly studied, only few researchers investigated the inside-of-the-foot kick, which is one of the most frequently performed techniques during games. In particular, little knowledge is available about differences in kinematics when kicking with the preferred and non-preferred leg. A motion analysis system recorded the three-dimensional coordinates of reflective markers placed upon the body of nine amateur soccer players (23.0 ± 2.1 years, BMI 22.2 ± 2.6 kg/m2), who performed 30 pass-kicks each, 15 with the preferred and 15 with the non-preferred leg. We investigated skill kinematics while maintaining a perspective on the complete picture of movement, looking for laterality related differences. The main focus was laid on: anatomical angles, contribution of upper limbs in kick biomechanics, kinematics of the body Center of Mass (CoM), which describes the whole body movement and is related to balance and stability. When kicking with the preferred leg, CoM displacement during the ground-support phase was 13% higher (p<0.001), normalized CoM height was 1.3% lower (p<0.001) and CoM velocity 10% higher (p<0.01); foot and shank velocities were about 5% higher (p<0.01); arms were more abducted (p<0.01); shoulders were rotated more towards the target (p<0.01, 6° mean orientation difference). We concluded that differences in motor control between preferred and non-preferred leg kicks exist, particularly in the movement velocity and upper body kinematics. Coaches can use these results to provide effective instructions to players in the learning process, moving their focus on kicking speed and upper body behavior

scholarly journals Concurrent Validity of a Portable Force Plate Using Vertical Jump Force–Time Characteristics

2018 ◽  
Vol 34 (5) ◽  
pp. 410-413 ◽  
Author(s):  
Jason Lake ◽  
Peter Mundy ◽  
Paul Comfort ◽  
John J. McMahon ◽  
Timothy J. Suchomel ◽  
...  
Keyword(s):  
Concurrent Validity ◽  
Vertical Jump ◽  
Reaction Force ◽  
Force Plate ◽  
Vertical Force ◽  
Jump Height ◽  
Strength Index ◽  
Limits Of Agreement ◽  
Force Time ◽  
Plate System

This study examined concurrent validity of countermovement vertical jump reactive strength index modified and force–time characteristics recorded using a 1-dimensional portable and laboratory force plate system. Twenty-eight men performed bilateral countermovement vertical jumps on 2 portable force plates placed on top of 2 in-ground force plates, both recording vertical ground reaction force at 1000 Hz. Time to takeoff; jump height; reactive strength index modified; and braking and propulsion impulse, mean net force, and duration were calculated from the vertical force from both force plate systems. Results from both systems were highly correlated (r ≥ .99). There were small (d < 0.12) but significant differences between their respective braking impulse, braking mean net force, propulsion impulse, and propulsion mean net force (P < .001). However, limits of agreement yielded a mean value of 1.7% relative to the laboratory force plate system (95% confidence limits, 0.9%–2.5%), indicating very good agreement across all of the dependent variables. The largest limits of agreement were for jump height (2.1%), time to takeoff (3.4%), and reactive strength index modified (3.8%). The portable force plate system provides a valid method of obtaining reactive strength measures, and several underpinning force–time variables, from unloaded countermovement vertical jump. Thus, practitioners can use both force plates interchangeably.

scholarly journals Association between Changes in Swimming Velocity, Vertical Center of Mass Position, and Projected Frontal Area during Maximal 200-m Front Crawl

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 60
Author(s):  
Sohei Washino ◽  
Akihiko Murai ◽  
Hirotoshi Mankyu ◽  
Yasuhide Yoshitake
Keyword(s):  
Inverse Kinematics ◽  
Center Of Mass ◽  
Three Dimensional ◽  
Frontal Area ◽  
Whole Body ◽  
Swimming Velocity ◽  
Front Crawl ◽  
Motion Data ◽  
Mass Position ◽  
Shape Data

We examined the association between changes in swimming velocity, vertical center of mass (CoM) position, and projected frontal area (PFA) during maximal 200-m front crawl. Three well-trained male swimmers performed a single maximal 200-m front crawl in an indoor 25-m pool. Three-dimensional (3D) shape data of the whole body were fitted to 3D motion data during swimming by using inverse kinematics computation to estimate PFA accurately. Swimming velocity decreased, the vertical CoM position was lowered, and PFA increased with swimming distance. There were significant correlations between swimming velocity and vertical CoM position (|r| = 0.797–0.982) and between swimming velocity and PFA (|r| = 0.716–0.884) for each swimmer. These results suggest that descent of the swimmer’s body and increasing PFA with swimming distance are associated with decreasing swimming velocity, although the causal factor remains unclear.

EVALUATION OF A COMPUTER-SIMULATION MODEL FOR HUMAN AMBULATION ON STILTS

2004 ◽  
Vol 04 (03) ◽  
pp. 283-303 ◽  
Author(s):  
CHRISTOPHER S. PAN ◽  
KIMBERLY M. MILLER ◽  
SHARON CHIOU ◽  
JOHN Z. WU
Keyword(s):  
Computer Simulation ◽  
Ground Reaction Force ◽  
Center Of Mass ◽  
Reaction Force ◽  
Construction Workers ◽  
Whole Body ◽  
Vertical Ground Reaction Force ◽  
Actual Measurement ◽  
Increased Risk ◽  
Vertical Ground

Stilts are elevated tools that are frequently used by construction workers to raise workers 18 to 40 inches above the ground without the burden of erecting scaffolding or a ladder. Some previous studies indicated that construction workers perceive an increased risk of injury when working on stilts. However, no in-depth biomechanical analyses have been conducted to examine the fall risks associated with the use of stilts. The objective of this study is to evaluate a computer-simulation stilts model. Three construction workers were recruited for walking tasks on 24-inch stilts. The model was evaluated using whole body center of mass and ground reaction forces. A PEAK™ motion system and two Kistler™ force platforms were used to collect data on both kinetic and kinematic measures. Inverse- and direct-dynamics simulations were performed using a model developed using commercial software — ADAMS and LifeMOD. For three coordinates (X, Y, Z) of the center of mass, the results of univariate analyses indicated very small variability for the mean difference between the model predictions and the experimental measurements. The results of correlation analyses indicated similar trends for the three coordinates. Plotting the resultant and vertical ground reaction force for both right and left feet showed small discrepancies, but the overall shape was identical. The percentage differences between the model and the actual measurement for three coordinates of the center of mass, as well as resultant and vertical ground reaction force, were within 20%. This newly-developed stilt walking model may be used to assist in improving the design of stilts.

Accuracy of a Vertical Jump Contact Mat for Determining Jump Height and Flight Time

2015 ◽  
Vol 29 (4) ◽  
pp. 877-881 ◽  
Author(s):  
Tyler D. Whitmer ◽  
Andrew C. Fry ◽  
Charles M. Forsythe ◽  
Matthew J. Andre ◽  
Michael T. Lane ◽  
...  
Keyword(s):  
Vertical Jump ◽  
Flight Time ◽  
Jump Height

scholarly journals Assessing the Validity of the MyJump2 App for Measuring Different Jumps in Professional Cerebral Palsy Football Players: An Experimental Study (Preprint)

2018 ◽  
Author(s):  
Victor Coswig ◽  
Anselmo De Athayde Costa E Silva ◽  
Matheus Barbalho ◽  
Fernando Rosch De Faria ◽  
Claudio D Nogueira ◽  
...  
Keyword(s):  
Cerebral Palsy ◽  
Injury Risk ◽  
Mobile Apps ◽  
Vertical Jump ◽  
Field Evaluation ◽  
Flight Time ◽  
Jump Height ◽  
Validity And Reliability ◽  
Jump Performance ◽  
P 16

BACKGROUND Vertical jumps can be used to assess neuromuscular status in sports performance. This is particularly important in Cerebral Palsy Football (CP Football) because players are exposed to high injury risk, but it may be complicated because the gold standard for assessing jump performance is scarce in field evaluation. Thus, field techniques, such as mobile apps, have been proposed as an alternative method for solving this problem. OBJECTIVE This study aims to evaluate the reliability of the measures of the MyJump2 app to assess vertical jump performance in professional CP Football. METHODS We assessed 40 male CP Football athletes (age 28.1 [SD 1.4] years, weight 72.5 [SD 6.2] kg, and height 176 [SD 4.2] cm) through the countermovement jump (CMJ) and squat jump (SJ) using a contact mat. At the same time, we assessed the athletes using the MyJump2 app. RESULTS There were no significant differences between the instruments in SJ height (P=.12) and flight time (P=.15). Additionally, there were no significant differences between the instruments for CMJ in jump height (P=.16) and flight time (P=.13). In addition, it was observed that there were significant and strong intraclass correlations in all SJ variables varying from 0.86 to 0.89 (both P<.001), which was classified as “almost perfect.” Similar results were observed in all variables from the CMJ, varying from 0.92 to 0.96 (both P ≤.001). CONCLUSIONS We conclude that the MyJump2 app presents high validity and reliability for measuring jump height and flight time of the SJ and CMJ in CP Football athletes.

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