scholarly journals A comparison of mechanical parameters between the counter movement jump and drop jump in Biathletes

2012 ◽  
Vol 34 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Henryk Król ◽  
Władysław Mynarski
Keyword(s):  
Vertical Jump ◽  
Muscular Activity ◽  
Lower Limbs ◽  
Drop Jump ◽  
Mean Power ◽  
Line System ◽  
Counter Movement Jump ◽  
Drop Jumps ◽  
Reaction Forces ◽  
Vertical Jumps

AbstractThe main objective of the study was to determine to what degree higher muscular activity, achieved by increasedload in the extension phase (eccentric muscle action) of the vertical jump, affects the efficiency of the vertical jump.Sixteen elite biathletes participated in this investigation. The biathletes performed tests that consisted of five, single“maximal” vertical jumps (counter movement jump - CMJ) and five, single vertical jumps, in which the task was totouch a bar placed over the jumping biathletes (specific task counter movement jump - SCMJ). Then, they performedfive, single drop jumps from an elevation of 0.4m (DJ). Ground reaction forces were registered using the KISTLER9182C force platform. MVJ software was used for signal processing (Król, 1999) and enabling calculations forkinematic and kinetic parameters of the subject’s jump movements (on-line system). The results indicate that onlyheight of the jump (h) and mean power (Pmean) during the takeoff are statistically significant. Both h and Pmean arehigher in the DJ. The results of this study may indicate that elite biathletes are well adapted to eccentric work of thelower limbs, thus reaching greater values of power during the drop jump. These neuromuscular adaptive changes mayallow for a more dynamic and efficient running technique.

scholarly journals Hindlimb muscular activity, kinetics and kinematics of cats jumping to their maximum achievable heights

1981 ◽  
Vol 91 (1) ◽  
pp. 73-86 ◽  
Author(s):  
F. E. Zajac ◽  
M. R. Zomlefer ◽  
W. S. Levine
Keyword(s):  
Vertical Jump ◽  
Muscular Activity ◽  
Dynamic State ◽  
Extensor Muscles ◽  
Ankle Joints ◽  
Flexor Muscles ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces ◽  
Propulsion Phase

Cats were trained to jump from a force platform to their maximum achievable heights. Vertical ground reaction forces developed by individual hindlimbs showed that the propulsion phase consists of two epochs. During the initial “preparatory phase' the cat can traverse many different paths. Irrespective of the path traversed, however, the cat always attains the same position, velocity and momentum at the end of this phase. Starting from this dynamic state the cat during the subsequent “launching phase' (about 150 ms long) generates significant propulsion as its hindlimbs develop force with identical, stereotypic profiles. Cinematographic data, electromyographic data, and computed torques about the hip, knee and ankle joints indicate that during the jump proximal extensor musculature is activated before distal musculature. During terminal experiments when the hindlimb was set at positions corresponding to those in the jump, isometric torques produced by tetanic stimulation of groups of extensor and flexor muscles were compared with computed torques developed by the same cat during previous jumps. These comparisons suggest that extensor muscles of the hindlimb are fully activated during the maximal vertical jump.

scholarly journals Prediction of Myoelectric Biomarkers in Post-Stroke Gait

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5334
Author(s):  
Iqram Hussain ◽  
Se-Jin Park
Keyword(s):  
Muscular Activity ◽  
Classification Performance ◽  
Lower Limbs ◽  
Training Dataset ◽  
Control Group ◽  
Mean Power ◽  
Predictive Tool ◽  
Post Stroke ◽  
Healthy Elderly ◽  
Power Frequency

Electromyography (EMG) is sensitive to neuromuscular changes resulting from ischemic stroke and is considered a potential predictive tool of post-stroke gait and rehabilitation management. This study aimed to evaluate the potential myoelectric biomarkers for the classification of stroke-impaired muscular activity of the stroke patient group and the muscular activity of the control healthy adult group. We also proposed an EMG-based gait monitoring system consisting of a portable EMG device, cloud-based data processing, data analytics, and a health advisor service. This system was investigated with 48 stroke patients (mean age 70.6 years, 65% male) admitted into the emergency unit of a hospital and 75 healthy elderly volunteers (mean age 76.3 years, 32% male). EMG was recorded during walking using the portable device at two muscle positions: the bicep femoris muscle and the lateral gastrocnemius muscle of both lower limbs. The statistical result showed that the mean power frequency (MNF), median power frequency (MDF), peak power frequency (PKF), and mean power (MNP) of the stroke group differed significantly from those of the healthy control group. In the machine learning analysis, the neural network model showed the highest classification performance (precision: 88%, specificity: 89%, accuracy: 80%) using the training dataset and highest classification performance (precision: 72%, specificity: 74%, accuracy: 65%) using the testing dataset. This study will be helpful to understand stroke-impaired gait changes and decide post-stroke rehabilitation.

Acute effect of post activation potentiation using drop jumps on repeated sprints combined with vertical jumps in young handball players

2020 ◽  
pp. 1-8
Author(s):  
Mahfoodha Al Kitani ◽  
Ahmed Ambussaidi ◽  
Majid Al Busafi ◽  
Badriya Al-Hadabi ◽  
Radhouane Haj Sassi ◽  
...  
Keyword(s):  
Reference Value ◽  
Acute Effect ◽  
Drop Jump ◽  
Countermovement Jump ◽  
Jump Performance ◽  
Warm Up ◽  
Repeated Sprints ◽  
Counter Movement Jump ◽  
Drop Jumps ◽  
Study Participants

BACKGROUND: The use of post-activation potentiation (PAP) exercises at the end of the warm-up may increase muscles nerve conduction speed and per consequent improve speed, strength and explosive power performances. OBJECTIVE: To assess the effect of PAP during warm-up using vertical or horizontal drop jumps on repeated sprints performance combined with countermovement jump in young handball players. METHODS: 12 young handball players participated in this study. Participants realized 3 randomized warm-up protocols: a warm-up without PAP, a warm-up with PAP using vertical drop jumps, and a warm-up with PAP using horizontal drop jumps. After the assigned PAP protocol, the subject realized a counter movement jump as a reference value (CMJr), and thereafter repeated sprint tests with and without changing of direction (six maximal 2 × 12.5 m shuttle sprints and six maximal 25 m straight sprints, respectively) combined with vertical jumping. RESULTS: Horizontal drop jump during warm-up showed larger improvements in repeated sprints performance with and without change of direction for the parameters best time and mean time, compared with warm up without drop jumps (p< 0.01) and warm up with vertical drop jumps (p< 0.05). Vertical drop jump performance during warm-up induced greater gains in countermovement jump reference value in comparison with warm up without drop jump (p< 0.01), or warm up with horizontal drop jump (p< 0.01). CONCLUSION: PAP during warm-up using horizontal drop jump improves repeated sprints performance with and without changing of direction while PAP using vertical drop jump improves CMJ reference value.

A Comparison of the Kinetic and Kinematic Characteristics of Plyometric Drop-Jump and Pendulum Exercises

1998 ◽  
Vol 14 (3) ◽  
pp. 260-275 ◽  
Author(s):  
Neil E. Fowler ◽  
Adrian Lees
Keyword(s):  
Training Stimulus ◽  
Reaction Force ◽  
Drop Jump ◽  
Coordination Strategies ◽  
Kinematic Characteristics ◽  
Drop Jumps ◽  
Reaction Forces ◽  
Cross Correlations ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces

The aim of this study was to compare the kinetic and kinematic characteristics of plyometric drop-jump and pendulum exercises. Exercises were filmed (100 Hz) from the sagittal view and manually digitized; the data were smoothed and differentiated using cross-validated quintic splines. Ground reaction force data were sampled using a Kistler force platform sampling at 500 Hz. Differences between movement amplitudes and coordination strategies were assessed usingttests and conjugate cross-correlations. Pendulum exercises involved a greater range of motion at the ankle and knee but less motion at the hip joint than drop-jumps. Although different in absolute terms, the exercises used a similar coordination strategy. Drop-jumps resulted in greater peak vertical ground reaction forces than the pendulum exercises although the latter involved a greater net impulse. The similarity between the movement patterns for the two modes of exercise led to the conclusion that pendulum exercises offer a training stimulus similar to that of drop-jumps.

Lower Limb Kinetics and Kinematics during Two Different Jumping Methods

2015 ◽  
Vol 22 ◽  
pp. 29-35 ◽  
Author(s):  
Yang Shu ◽  
Dong Sun ◽  
Qiu Li Hu ◽  
Yan Zhang ◽  
Jian She Li ◽  
...  
Keyword(s):  
Lower Limb ◽  
Impact Force ◽  
Vertical Jump ◽  
Lower Limbs ◽  
Countermovement Jump ◽  
Kinematic Parameters ◽  
Squat Jump ◽  
High Level ◽  
Vertical Jumps ◽  
Kinematics Parameters

The purpose of the study is to investigate into the dynamic and kinematic parameters of lower limbs about two types of jump high-level basketball athlete doing: countermovement jump and squat jump. There were distinctively different in jump height between two types. Kinetics and kinematics parameters of squat jump were less than countermovement jump. Using Vertical Jumps countermovement jump can increase the height of vertical jump effectively. These jumps all can cushion the pressure of impact force in landing phase.

Kinesiological Factors in Vertical Jump Performance: Differences among Individuals

1997 ◽  
Vol 13 (1) ◽  
pp. 24-44 ◽  
Author(s):  
Luis F. Aragón-Vargas ◽  
M. Melissa Gross
Keyword(s):  
Vertical Jump ◽  
Video Data ◽  
Mechanical Power ◽  
Whole Body ◽  
Jump Performance ◽  
Physically Active ◽  
Reaction Forces ◽  
Body Level ◽  
Vertical Jumps ◽  
Level Of Analysis

The purpose of this study was to investigate the kinesiological factors that distinguish good jumpers from poor ones, in an attempt to understand the critical factors in vertical jump performance(VJP).Fifty-two normal, physically active male college students each performed five maximal vertical jumps with arms akimbo. Ground reaction forces and video data were collected during the jumps. Subjects' strength was tested isometrically. Thirty-five potential predictor variables were calculated for statistical modeling by multiple-regression analysis. At the whole-body level of analysis, the best models (which included peak and average mechanical power) accounted for 88% ofVJPvariation (p< .0005). At the segmental level, the best models accounted for 60% of variation inVJP(p< .0005). Unexpectedly, coordination variables were not related toVJP. These data suggested thatVJPwas most strongly associated with the mechanical power developed during jump execution.

Dynamic Force Response of Human Legs due to Vertical Jumps

2011 ◽  
Author(s):  
Kinjal Prajapati ◽  
Fred Barez ◽  
James Kao ◽  
David Wagner
Keyword(s):  
Knee Joint ◽  
Hip Joint ◽  
Vertical Jump ◽  
Injury Mechanism ◽  
Ankle Injuries ◽  
Musculoskeletal Simulation ◽  
Joint Reaction Forces ◽  
Reaction Forces ◽  
Vertical Jumps ◽  
Joint Reaction

Jumping is a natural exertion that occurs during a variety of human activities including playing sports, working, skateboarding, dancing, escaping from hazardous events, rescue activities, and many others. During jumping, the ankles in particular are expected to support the entire body weight of the jumper and that may lead to ankle injuries. Each year hundreds of patients are treated for ankle sprains/strains with ankle fractures as one of the most common injuries treated by orthopedists and podiatrists. The knee joint is also considered the most-often injured joint in the entire human body. Although the general anatomy of the lower extremities is fairly well understood, an understanding of the injury mechanism during these jumping tasks is not well understood. The aim of this study is to determine the reaction forces exerted on legs and joints due to vertical jumps, through musculoskeletal simulation and experimental studies to better understand the dynamic jump process and the injury mechanism. The joint reaction forces and moments exerted on the ankle, knee and hip joint during takeoff and extreme squat landing of a vertical jump were determined through the application of musculoskeletal simulation. It is concluded that during extreme squat landing of a vertical jump, joint reaction forces and moments were highest in proximal/distal and anteroposterior direction may cause most likely injury to the hip joint ligaments, ankle fracture and knee joint, respectively.

scholarly journals Effect of drop jump technique on the reactive strength index

2016 ◽  
Vol 52 (1) ◽  
pp. 157-164 ◽  
Author(s):  
Artur Struzik ◽  
Grzegorz Juras ◽  
Bogdan Pietraszewski ◽  
Andrzej Rokita
Keyword(s):  
Force Plate ◽  
Jump Height ◽  
Drop Jump ◽  
Plyometric Training ◽  
Strength Index ◽  
Basketball Players ◽  
Male Youth ◽  
Kinematic Data ◽  
Drop Jumps ◽  
Reaction Forces

AbstractThe basic drill of plyometric training aimed at improving lower limb power and jump height is a drop jump. This exercise can be performed using different techniques, which substantially affects jump variables. Therefore, the aim of this study was to compare the values of the reactive strength index (RSI) for countermovement drop jumps (CDJs) and bounce drop jumps (BDJs). The study was carried out in a group of 8 male youth basketball players. The tests were conducted using the AMTI BP600900 force plate to measure ground reaction forces and the Noraxon MyoMotion system to record kinematic data. Each player performed two CDJs and two BDJs from the height of 15, 30, 45 and 60 cm. The RSI was calculated as a ratio of jump height and contact time. Moreover, the RSI was determined for the amortization and take-off phases separately. Significant differences (p < 0.05) between RSI values for CDJs and BDJs were recorded for jumps from 30, 45 and 60 cm. Differences in RSI values for jumps from 15 cm were not significant. Furthermore, CDJ height values were significantly higher (p < 0.05) than the values recorded for BDJs. Times of contact, amortization and take-off during BDJs were significantly shorter (p < 0.05) than the respective values obtained for CDJs. Therefore, the use of the RSI to monitor plyometric training should be based on the drop jump technique that is commonly performed by basketball players.

scholarly journals The Occurrence of Different Vertical Jump Types in Basketball Competition and their Relationship with Lower-Body Speed-Strength Qualities.

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Scott Talpey ◽  
Andrew Smyth ◽  
Mathew O'Grady ◽  
Matthew Morrison ◽  
Warren Young
Keyword(s):  
Vertical Jump ◽  
Lower Body ◽  
Basketball Players ◽  
Squat Jump ◽  
Professional Basketball ◽  
Counter Movement Jump ◽  
One Step ◽  
Run Up ◽  
Standing Start ◽  
Vertical Jumps

Jumps occur frequently in basketball and can be executed from a single-leg take-off following a run-up or bilaterally from a standing start. Understanding the type of jumps performed in competition and how different muscular qualities influence their performance, informs training prescription. Firstly, to quantify the occurrence of different jump types performed in competition an analysis of 15 semi-professional basketball games was undertaken. Secondly, to understand the influence of muscular qualities on performance of different jump types, Semi-professional male basketball players (N=17) performed jump tests; standing vertical jump, running vertical jumps with a double leg take-off (RVJ2) and a single leg take-off (RVJ1) and tests of lower-body speed-strength; reactive strength index (RSI) from a drop jump, counter movement jump (CMJ) and squat jump.  A stationary approach was employed for 69%, a running approach for 26% and a one-step approach for 5%. RVJ1 displayed non-significant (P=0.07) moderate correlation with jump height attained from the CMJ (r=0.439) and a very large (r =.806) significant (P<0.01) correlation with RSI. Most jumps were executed from a stationary start with a bilateral take-off while a run-up occurred prior to a substantial proportion of jumps. Jumps with a single-leg take-off from a run-up strongly correlate with RSI.

scholarly journals VERTICAL JUMPING PERFORMANCE RELATES TO SPRINTING PERFORMANCE OVER SHORT DISTANCES AND DIFFERENT SECTIONS

2021 ◽  
Vol 2 (2021) ◽  
pp. 17-27
Author(s):  
Sebastian Möck ◽  
◽  
René Hartmann ◽  
Klaus Wirth ◽  
◽  
...  
Keyword(s):  
Cycle Performance ◽  
Drop Jump ◽  
Countermovement Jump ◽  
Jump Performance ◽  
Squat Jump ◽  
Mean Values ◽  
Vertical Jumping ◽  
Drop Jumps ◽  
Reaction Forces ◽  
High Level

A high level of sprinting performance is relevant in various sports. Because of the transition of movement patterns in different sprint sections there is a shift in the relevance of speed-strength of the knee and hip extensors, and stretch-shortening cycle performance seems conceivable. Fifty-six physical education students (23.70 ± 3.00 years, 176.9 ± 8.10cm, 74.20 ± 10.30kg) were investigated. They performed sprints up to 30m in which different sections were analyzed and vertical jumps (squat jump, countermovement jump, drop jump from different dropping heights). Vertical jumping tests in squat jump and countermovement jump revealed mean values of 31.95 ± 6.56cm and 34.28 ± 7.47cm, respectively, while the drop jumps showed mean RSI values between 155.11 ± 36.77 and 168.24 ± 36.29 dependent on the dropping height. The sprint test showed a mean performance of 4.464 ± .343s (30m). The correlational analysis showed significant correlations (p < .01) for vertical jumping height with all sprinting sections (r = −.652 to −.834). Drop jump performance also showed significant correlations (p < .01) with all the sections (r = −.379 to −.594). The results let us hypothesize that the observed sample generated similar ground-reaction forces in the sprint and drop jump from a height of 40 cm.

Sign in / Sign up

Export Citation Format

Share Document