Effects Of Different Levels Of Assisted Jumping On Vertical Jump Height And Relative Ground Reaction Force

2010 ◽  
Vol 42 ◽  
pp. 370-371 ◽  
Author(s):  
Tai T. Tran ◽  
Lee E. Brown ◽  
Jared W. Coburn ◽  
Scott K. Lynn ◽  
Nicole C. Dabbs ◽  
...  
2010 ◽  
Vol 26 (4) ◽  
pp. 508-511 ◽  
Author(s):  
Loren Z.F. Chiu ◽  
George J. Salem

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.


2021 ◽  
Author(s):  
Morikawa Masanori ◽  
Maeda Noriaki ◽  
Komiya Makoto ◽  
Kobayashi Toshiki ◽  
Urabe Yukio

Abstract Background: Ankle orthotics decreases the maximal vertical jump height. It is essential to maximize jump height and minimize ground contact time during athletic performance. However, the effect of ankle orthotics on athletic performance has not been reported. We aimed to investigate the effect of ankle orthotics on squat jump (SJ), countermovement jump (CMJ), and repetitive rebound jump (RJ) performance and the relationship between jump performance and restriction in sagittal ankle range of motion. Methods: Twenty healthy volunteers performed SJ, CMJ, repetitive RJ under no-orthosis and two orthotic conditions (orthosis 1 and orthosis 2). During SJ and CMJ, we measured the vertical ground reaction force and calculated the following parameters: jump height, peak vertical ground reaction force, rate of force development, net vertical impulse, and peak power. During repetitive RJ, the jump height, contact time, and RJ index were measured. A two-dimensional motion analysis was used to quantify the ankle range of motion in the sagittal plane during SJ, CMJ, and repetitive RJ. Results: Multivariate analysis of variance and the post hoc test showed a significant decrease in the vertical jump height (p = 0.003), peak power (p = 0.007), and maximum plantarflexion and dorsiflexion angles (p <0.001) during SJ using orthosis 2 compared to those using the no-orthosis condition. Additionally, orthosis 2 significantly decreased the jump height at the end of repetitive RJ (p = 0.046), during which a significant negative correlation was found between jump height and maximum dorsiflexion angle (r = 0.485, p = 0.030). Conclusions: An ankle orthosis-induced restriction of dorsiflexion is associated with a reduction in jump height during static jump and repetitive RJ performance.


2017 ◽  
Vol 38 (11) ◽  
pp. 842-846 ◽  
Author(s):  
Hsien-Te Peng ◽  
Cong Khuat ◽  
Thomas Kernozek ◽  
Brian Wallace ◽  
Shin-Liang Lo ◽  
...  

AbstractOur purpose was to evaluate the vertical ground reaction force, impulse, moments and powers of hip, knee and ankle joints, contact time, and jump height when performing a drop jump from different drop heights based on the percentage of a performer’s maximum vertical jump height (MVJH). Fifteen male Division III athletes participated voluntarily. Eleven synchronized cameras and two force platforms were used to collect data. One-way repeated-measures analysis of variance tests were used to examine the differences between drop heights. The maximum hip, knee and ankle power absorption during 125%MVJH and 150%MVJH were greater than those during 75%MVJH. The impulse during landing at 100%MVJH, 125%MVJH and 150%MVJH were greater than 75%MVJH. The vertical ground reaction force during 150%MVJH was greater than 50%MVJH, 75%MVJH and 100%MVJH. Drop height below 75%MVJH had the most merits for increasing joint power output while having a lower impact force, impulse and joint power absorption. Drop height of 150%MVJH may not be desirable as a high-intensity stimulus due to the much greater impact force, increasing the risk of injury, without increasing jump height performance.


2021 ◽  
pp. 1-8
Author(s):  
Junta Iguchi ◽  
Minoru Matsunami ◽  
Tatsuya Hojo ◽  
Yoshihiko Fujisawa ◽  
Kenji Kuzuhara ◽  
...  

BACKGROUND: Few studies have investigated the variations in body composition and performance in Japanese collegiate American-football players. OBJECTIVE: To clarify what characterizes competitors at the highest levels – in the top division or on the starting lineup – we compared players’ body compositions and performance test results. METHODS: This study included 172 players. Each player’s body composition and performance (one-repetition maximum bench press, one-repetition maximum back squat, and vertical jump height) were measured; power was estimated from vertical jump height and body weight. Players were compared according to status (starter vs. non-starter), position (skill vs. linemen), and division (1 vs. 2). Regression analysis was performed to determine characteristics for being a starter. RESULTS: Players in higher divisions and who were starters were stronger and had more power, greater body size, and better performance test results. Players in skill positions were relatively stronger than those in linemen positions. Vertical jump height was a significant predictor of being a starter in Division 1. CONCLUSION: Power and vertical jump may be a deciding factor for playing as a starter or in a higher division.


2020 ◽  
Vol 38 (13) ◽  
pp. 1475-1487 ◽  
Author(s):  
Rodrigo Ramirez-Campillo ◽  
Javier Sanchez-Sanchez ◽  
Blanca Romero-Moraleda ◽  
Javier Yanci ◽  
Antonio García-Hermoso ◽  
...  

2014 ◽  
Vol 20 (3) ◽  
pp. 303-309 ◽  
Author(s):  
Gleber Pereira ◽  
Paulo B. de Freitas ◽  
Jose A. Barela ◽  
Carlos Ugrinowitsch ◽  
André L. F. Rodacki ◽  
...  

The aim of this study was to describe the intersegmental coordination and segmental contribution during intermittent vertical jumps performed until fatigue. Seven male visited the laboratory on two occasions: 1) the maximum vertical jump height was determined followed by vertical jumps habituation; 2) participants performed intermittent countermovement jumps until fatigue. Kinematic and kinetic variables were recorded. The overall reduction in vertical jump height was 5,5%, while the movement duration increased 10% during the test. The thigh segment angle at movement reversal significantly increased as the exercise progressed. Non-significant effect of fatigue on movement synergy was found for the intersegmental coordination pattern. More than 90% of the intersegmental coordination was explained by one coordination pattern. Thigh rotation contributed the most to the intersegmental coordination pattern, with the trunk second and the shank the least. Therefore, one intersegmental coordination pattern is followed throughout the vertical jumps until fatigue and thigh rotation contributes the most to jump height.


Author(s):  
Matthew R. Maulit ◽  
David C. Archer ◽  
Whitney D. Leyva ◽  
Cameron N. Munger ◽  
Megan A. Wong ◽  
...  

Background: Recent research has compared explosive deadlift to kettlebell training observing their effects on strength. The kettlebell swing is a popular practical exercise as it shares share a hip hinge movement with the explosive deadlift, but the two have not been compared. Objectives: The purpose of this study was to compare the effects of kettlebell swing vs. explosive deadlift training on strength and power. Methods: Thirty-one recreationally resistance-trained men (age = 23.1 ± 2.3 years, height = 175.5 ± 6.6 cm, mass = 83.9 ± 13.8 kg, 1RM deadlift = 159.9 ± 31.7 kg) were randomly assigned to one of two groups [kettlebell swing group (KBG) n = 15, or explosive deadlift group (EDLG) n = 16]. Vertical jump height, isometric mid-thigh pull (MTP), and 1RM deadlift were measured pre and post training. Both groups trained twice per week for 4 weeks. Volume and load were increased after the first 2 weeks of training. Results: A 2 (time) x 2 (group) mixed factor ANOVA revealed a significant (P<0.05) increase in deadlift 1RM (pre: 159.9 ± 31.7 kg, post: 168.9 ± 31.8 kg) and vertical jump height (pre: 56.6 ± 9.9 cm, post: 57.9 ± 9.7 cm) for both groups, but were not significantly different between groups. There were no significant changes in MTP. Conclusions: Strength and conditioning professionals may use both kettlebell swings and explosive deadlifts to increase deadlift strength and vertical jump power.


2021 ◽  
pp. 149-157
Author(s):  
Manuel V. Garnacho-Castaño ◽  
Marcos Faundez-Zanuy ◽  
Noemí Serra-Payá ◽  
José L. Maté-Muñoz ◽  
Josep López-Xarbau ◽  
...  

This study aimed to assess the reliability and validity of the Polar V800 to measure vertical jump height. Twenty-two physically active healthy men (age: 22.89 ± 4.23 years; body mass: 70.74 ± 8.04 kg; height: 1.74 ± 0.76 m) were recruited for the study. The reliability was evaluated by comparing measurements acquired by the Polar V800 in two identical testing sessions one week apart. Validity was assessed by comparing measurements simultaneously obtained using a force platform (gold standard), high-speed camera and the Polar V800 during squat jump (SJ) and countermovement jump (CMJ) tests. In the test-retest reliability, high intraclass correlation coefficients (ICCs) were observed (mean: 0.90, SJ and CMJ) in the Polar V800. There was no significant systematic bias ± random errors (p > 0.05) between test-retest. Low coefficients of variation (<5%) were detected in both jumps in the Polar V800. In the validity assessment, similar jump height was detected among devices (p > 0.05). There was almost perfect agreement between the Polar V800 compared to a force platform for the SJ and CMJ tests (Mean ICCs = 0.95; no systematic bias ± random errors in SJ mean: -0.38 ± 2.10 cm, p > 0.05). Mean ICC between the Polar V800 versus high-speed camera was 0.91 for the SJ and CMJ tests, however, a significant systematic bias ± random error (0.97 ± 2.60 cm; p = 0.01) was detected in CMJ test. The Polar V800 offers valid, compared to force platform, and reliable information about vertical jump height performance in physically active healthy young men.


2007 ◽  
Vol 23 (3) ◽  
pp. 180-189 ◽  
Author(s):  
Niell G. Elvin ◽  
Alex A. Elvin ◽  
Steven P. Arnoczky

Modern electronics allow for the unobtrusive measurement of accelerations outside the laboratory using wireless sensor nodes. The ability to accurately measure joint accelerations under unrestricted conditions, and to correlate them with jump height and landing force, could provide important data to better understand joint mechanics subject to real-life conditions. This study investigates the correlation between peak vertical ground reaction forces, as measured by a force plate, and tibial axial accelerations during free vertical jumping. The jump heights calculated from force-plate data and accelerometer measurements are also compared. For six male subjects participating in this study, the average coefficient of determination between peak ground reaction force and peak tibial axial acceleration is found to be 0.81. The coefficient of determination between jump height calculated using force plate and accelerometer data is 0.88. Data show that the landing forces could be as high as 8 body weights of the jumper. The measured peak tibial accelerations ranged up to 42 g. Jump heights calculated from force plate and accelerometer sensors data differed by less than 2.5 cm. It is found that both impact accelerations and landing forces are only weakly correlated with jump height (the average coefficient of determination is 0.12). This study shows that unobtrusive accelerometers can be used to determine the ground reaction forces experienced in a jump landing. Whereas the device also permitted an accurate determination of jump height, there was no correlation between peak ground reaction force and jump height.


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