scholarly journals Leg-Length in Relation to Selected Ballet Performance Indicators

2017 ◽  
Vol 32 (3) ◽  
pp. 165-169 ◽  
Author(s):  
CC Karpodini ◽  
MA Wyon ◽  
N Comoutos ◽  
Y Koutedakis
Keyword(s):  
Range Of Motion ◽  
Lower Limb ◽  
Vertical Jump ◽  
Limb Length ◽  
Leg Length ◽  
Countermovement Jump ◽  
Dance Movements ◽  
Exploratory Data ◽  
The Relationship ◽  
Negative Relationships

It is unclear whether the modern ballet body stereotype of long limbs is advantageous in dance performance. Therefore, we investigated the relationship between leg-length and selected dance movements representative of power, dexterity, and range of motion in ballet dancers at different competence levels. METHODS: The total of 10 recreational, 24 vocational, and 10 professional ballerinas volunteered. They were subjected to: a) lower limb-length measurements, b) power tests (vertical jump-sautés and unilateral countermovement jump-temps levé), c) dexterity tests (tendus and double battement frappes), and d) flexibility tests (lateral active and passive-développé à la seconde). RESULTS: For power, regression analyses revealed negative leg-length relationships in recreational dancers (p<0.05) and positive leg-length relationships in vocational dancers (p<0.05). We also found negative relationships between leg-length and dexterity in the vocational group (p=0.01). No significant predictions of leg-length on power, dexterity, and range of motion were found in professional dancers. Multiple comparisons revealed significant differences between groups only for dexterity (p<0.01) and range of motion (p<0.01). CONCLUSION: Based on selected movements representative of power, dexterity, and range of motion, the present exploratory data indicate that lower limb length is not a determinative criterion for ballet success. Further studies should investigate whether body stereotypes, such as long limbs, are linked to dance injuries.

Relationship between Closed-Linear-Kinetic-and Open-Kinetic-Chain Isokinetic Strength and Lower Extremity Functional Performance

2001 ◽  
Vol 10 (3) ◽  
pp. 196-204 ◽  
Author(s):  
John E. Kovaleski ◽  
Robert J. Heitman ◽  
Damon P.S. Andrew ◽  
Larry R. Gurchiek ◽  
Albert W. Pearsall
Keyword(s):  
Outcome Measures ◽  
Lower Limb ◽  
Functional Performance ◽  
Vertical Jump ◽  
Isokinetic Strength ◽  
Kinetic Chain ◽  
Isokinetic Muscle Strength ◽  
The Relationship ◽  
University Laboratory ◽  
Linear Kinetic

Context:Isokinetic strength and functional performance are used to assess recovery after rehabilitation. It is not known whether low-speed closed-linear-kinetic isokinetic muscle strength correlates with functional performance.Objective:To investigate the relationship between linear closed (CKC) and open (OKC) concentric isokinetic strength of the dominant lower-limb extensors and functional performance.Design:Correlational analysis.Setting:University laboratory.Participants:Thirty uninjured men and women (age = 20.9 ± 2.4 years).Main Outcome Measures:Peak CKC and OKC isokinetic strength and best score from a shuttle run for time, single-leg vertical jump, and single-leg hop for distance.Results:Neither lower-limb CKC nor OKC isokinetic strength measured at low speeds correlated highly with performance on the functional tasks of jumping, hopping, and speed/agility.Conclusions:Although the basis of both closed and open isokinetic strength must be appreciated, they should not be the only determinants of functional performance.

Relative Net Vertical Impulse Determines Jumping Performance

2011 ◽  
Vol 27 (3) ◽  
pp. 207-214 ◽  
Author(s):  
Tyler J. Kirby ◽  
Jeffrey M. McBride ◽  
Tracie L. Haines ◽  
Andrea M. Dayne
Keyword(s):  
Body Mass ◽  
Peak Power ◽  
Vertical Jump ◽  
Peak Force ◽  
Jump Height ◽  
Countermovement Jump ◽  
Jump Performance ◽  
Velocity Peak ◽  
Force Peak ◽  
The Relationship

The purpose of this investigation was to determine the relationship between relative net vertical impulse and jump height in a countermovement jump and static jump performed to varying squat depths. Ten college-aged males with 2 years of jumping experience participated in this investigation (age: 23.3 ± 1.5 years; height: 176.7 ± 4.5 cm; body mass: 84.4 ± 10.1 kg). Subjects performed a series of static jumps and countermovement jumps in a randomized fashion to a depth of 0.15, 0.30, 0.45, 0.60, and 0.75 m and a self-selected depth (static jump depth = 0.38 ± 0.08 m, countermovement jump depth = 0.49 ± 0.06 m). During the concentric phase of each jump, peak force, peak velocity, peak power, jump height, and net vertical impulse were recorded and analyzed. Net vertical impulse was divided by body mass to produce relative net vertical impulse. Increasing squat depth corresponded to a decrease in peak force and an increase in jump height and relative net vertical impulse for both static jump and countermovement jump. Across all depths, relative net vertical impulse was statistically significantly correlated to jump height in the static jump (r= .9337,p< .0001, power = 1.000) and countermovement jump (r= .925,p< .0001, power = 1.000). Across all depths, peak force was negatively correlated to jump height in the static jump (r= –0.3947,p= .0018, power = 0.8831) and countermovement jump (r= –0.4080,p= .0012, power = 0.9050). These results indicate that relative net vertical impulse can be used to assess vertical jump performance, regardless of initial squat depth, and that peak force may not be the best measure to assess vertical jump performance.

The effectiveness and influencing factors of the ‘Y’ line technique in reducing the leg length discrepancy after total hip arthroplasty

2021 ◽  
Author(s):  
Wenshu Jin ◽  
Huaqiang Sun ◽  
Xudong Duan ◽  
Yange Gu ◽  
zhang zhao ◽  
...  
Keyword(s):  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Lower Limb ◽  
Limb Length ◽  
Leg Length Discrepancy ◽  
Leg Length ◽  
X Ray ◽  
Length Discrepancy ◽  
Group A ◽  
Group B

Abstract Objective: To introduce a surgical technique (the ‘Y’ line technique) which is to control the leg length discrepancy (LLD) after total hip arthroplasty.Methods: A total of 350 patients were selected; 134 patients who were used the ‘Y’ line technique to control lower limb length were included in Group A and 166 patients treated with free hand methods to control lower limb length were included in Group B. 50 patients who were taken standard anteroposterior X-ray of bilateral hips preoperatively and used the ‘Y’ line technique during the operation were included in Group C. Results: The postoperative LLD of the three groups was statistically significant (p < 0.001). There were significant differences statistically in comparison between any two groups (P<0.01). Severe unequal length rates of the lower extremities (LLD > 10 mm) were 5.97% (8/134) in Group A, 14.3% (24/166) in Group B and 0% (0/50) in Group C – the difference was statistically significant (p < 0.001). There were significant differences between Group A and Group B, Group B and Group C (P < 0.05), but there was no significant difference between Group A and Group C (P = 0.078).Conclusion: The ‘Y’ line technique, which does not increase the operation time, can effectively reduce postoperative LLD. Insufficient internal rotation of the healthy lower extremity and the low projection position in the preoperative anteroposterior X-ray of bilateral hips were important factors affecting the accuracy of the ‘Y’ line technique.

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.

Short-Term Effects of Kinesio Taping on Muscle Recruitment Order During a Vertical Jump: A Pilot Study

2018 ◽  
Vol 27 (4) ◽  
pp. 319-326 ◽  
Author(s):  
Guillermo Mendez-Rebolledo ◽  
Rodrigo Ramirez-Campillo ◽  
Eduardo Guzman-Muñoz ◽  
Valeska Gatica-Rojas ◽  
Alexis Dabanch-Santis ◽  
...  
Keyword(s):  
Ground Reaction Force ◽  
Lower Limb ◽  
Vertical Jump ◽  
Reaction Force ◽  
Countermovement Jump ◽  
Short Term ◽  
Male Athletes ◽  
Squat Jump ◽  
Kinesio Taping ◽  
Recruitment Order

Context: Kinesio taping is commonly used in sports and rehabilitation settings with the aim of prevention and treatment of musculoskeletal injuries. However, limited evidence exists regarding the effects of 24 and 72 hours of kinesio taping on trunk and lower limb neuromuscular and kinetic performance during a vertical jump. Objective: The purpose of this study was to analyze the short-term effects of kinesio taping on height and ground reaction force during a vertical jump, in addition to trunk and lower limb muscle latency and recruitment order. Design: Single-group pretest–posttest. Setting: University laboratory. Participants: Twelve male athletes from different sports (track and field, basketball, and soccer). Interventions: They completed a single squat and countermovement jump at basal time (no kinesio taping), 24, and 72 hours of kinesio taping application on the gluteus maximus, biceps femoris, rectus femoris, gastrocnemius medialis, and longissimus. Main Outcome Measures: Muscle onset latencies were assessed by electromyography during a squat and countermovement jump, in addition to measurements of the jump height and normalized ground reaction force. Results: The kinesio taping had no effect after 24 hours on either the countermovement or squat jump. However, at 72 hours, the kinesio taping increased the jump height (P = .02; d = 0.36) and normalized ground reaction force (P = .001; d = 0.45) during the countermovement jump. In addition, 72-hour kinesio taping reduced longissimus onset latency (P = .03; d = 1.34) and improved muscle recruitment order during a countermovement jump. Conclusions: These findings suggest that kinesio taping may improve neuromuscular and kinetic performance during a countermovement jump only after 72 hours of application on healthy and uninjured male athletes. However, no changes were observed on a squat jump. Future studies should incorporate a control group to verify kinesio taping’s effects and its influence on injured athletes.

scholarly journals Force-Sensitive Mat for Vertical Jump Measurement to Assess Lower Limb Strength: Validity and Reliability Study (Preprint)

2021 ◽  
Author(s):  
Erik Vanegas ◽  
Yolocuauhtli Salazar ◽  
Raúl Igual ◽  
Inmaculada Plaza
Keyword(s):  
Lower Limb ◽  
Vertical Jump ◽  
Sampling Frequency ◽  
Coefficient Of Determination ◽  
Jump Height ◽  
Countermovement Jump ◽  
Raw Data ◽  
Vertical Jump Height ◽  
High Sampling ◽  
The Impact

BACKGROUND Vertical jump height is widely used in health care and sports fields to assess muscle strength and power from lower limb muscle groups. Different approaches have been proposed for vertical jump height measurement. Some commonly used approaches need no sensor at all; however, these methods tend to overestimate the height reached by the subjects. There are also novel systems using different kind of sensors like force-sensitive resistors, capacitive sensors, and inertial measurement units, among others, to achieve more accurate measurements. OBJECTIVE The objective of this study is twofold. The first objective is to validate the functioning of a developed low-cost system able to measure vertical jump height. The second objective is to assess the effects on obtained measurements when the sampling frequency of the system is modified. METHODS The system developed in this study consists of a matrix of force-sensitive resistor sensors embedded in a mat with electronics that allow a full scan of the mat. This mat detects pressure exerted on it. The system calculates the jump height by using the flight-time formula, and the result is sent through Bluetooth to any mobile device or PC. Two different experiments were performed. In the first experiment, a total of 38 volunteers participated with the objective of validating the performance of the system against a high-speed camera used as reference (120 fps). In the second experiment, a total of 15 volunteers participated. Raw data were obtained in order to assess the effects of different sampling frequencies on the performance of the system with the same reference device. Different sampling frequencies were obtained by performing offline downsampling of the raw data. In both experiments, countermovement jump and countermovement jump with arm swing techniques were performed. RESULTS In the first experiment an overall mean relative error (MRE) of 1.98% and a mean absolute error of 0.38 cm were obtained. Bland-Altman and correlation analyses were performed, obtaining a coefficient of determination equal to <i>R</i><sup>2</sup>=.996. In the second experiment, sampling frequencies of 200 Hz, 100 Hz, and 66.6 Hz show similar performance with MRE below 3%. Slower sampling frequencies show an exponential increase in MRE. On both experiments, when dividing jump trials in different heights reached, a decrease in MRE with higher height trials suggests that the precision of the proposed system increases as height reached increases. CONCLUSIONS In the first experiment, we concluded that results between the proposed system and the reference are systematically the same. In the second experiment, the relevance of a sufficiently high sampling frequency is emphasized, especially for jump trials whose height is below 10 cm. For trials with heights above 30 cm, MRE decreases in general for all sampling frequencies, suggesting that at higher heights reached, the impact of high sampling frequencies is lesser.

scholarly journals Relationships of the 5-Jump Test (5JT) Performance of Youth Players With Volleyball Specific’ Laboratory Tests for Explosive Power

2020 ◽  
Vol 14 (6) ◽  
pp. 155798832097768
Author(s):  
Karim Ben Ayed ◽  
Helmi Ben Saad ◽  
Mohamed Ali Hammami ◽  
Imed Latiri
Keyword(s):  
Peak Power ◽  
Laboratory Tests ◽  
Leg Length ◽  
Countermovement Jump ◽  
Squat Jump ◽  
Explosive Power ◽  
Jump Test ◽  
Volleyball Players ◽  
S Peak ◽  
The Relationship

Volleyball involves movements with and/or without horizontal approaches (i.e., spike jumps, jump setting, blocking). The 5-jump test (5JT) was suggested to assess lower limb explosive power of athletes competing in some disciplines (e.g., soccer, judo, running). It appears that no previous study has investigated the 5JT performance components in volleyball players. This study aimed to test the relationship between 5JT performance and two specific laboratory tests for explosive power (i.e., countermovement jump [CMJ] and squat jump [SJ]). Forty volleyball players (boys, mean age: 12.4 ± 0.8 years) were tested for 5JT, CMJ, and SJ tests. 5JT performance was expressed in absolute terms (m), and relative to leg length (5JTLL) and body mass (5JTBM). The SJ and CMJ tests were evaluated using the optojump photoelectric cells and the following data were collected: peak power (Pp) of jump (W, W.kg-0.67), peak jumping force (Fpeak, N), peak jumping velocity (Vpeak, m/s), peak heights of CMJ and SJ (CMJH and SJH, respectively, cm). Only significant ( p < .05) Pearson product-moment correlations ( r) > 0.30 were considered. 5JT performance was significantly correlated with SJ, Vpeak ( r = 0.90), SJH ( r = 0.88), Pp [W.kg-0.67 ( r = 0.86), W ( r = 0.72)], Fpeak ( r = 0.45); and CMJ, Vpeak ( r = 0.82), CMJH ( r = 0.80), Pp [W.kg-0.67 ( r = 0.89), W ( r = 0.85)], Fpeak ( r = 0.73). 5JTLL values were significantly related to SJ, Pp [W ( r = 0.81), W.kg-0.67 ( r = 0.74)], Vpeak ( r = 0.82); and CMJ, Pp [W ( r = 0.73), W.kg-0.67 ( r = 0.84)], Vpeak ( r = 0.75), Fpeak ( r = 0.67)]. 5JTBM values were significantly related to SJ, Pp (W, r = −0.43). To conclude, in youth volleyball players, the 5JT may be viewed as an explosive strength diagnostic instrument under field circumstances.

scholarly journals Force-Sensitive Mat for Vertical Jump Measurement to Assess Lower Limb Strength: Validity and Reliability Study

10.2196/27336 ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. e27336
Author(s):  
Erik Vanegas ◽  
Yolocuauhtli Salazar ◽  
Raúl Igual ◽  
Inmaculada Plaza
Keyword(s):  
Lower Limb ◽  
Vertical Jump ◽  
Sampling Frequency ◽  
Coefficient Of Determination ◽  
Jump Height ◽  
Countermovement Jump ◽  
Raw Data ◽  
Vertical Jump Height ◽  
High Sampling ◽  
The Impact

Background Vertical jump height is widely used in health care and sports fields to assess muscle strength and power from lower limb muscle groups. Different approaches have been proposed for vertical jump height measurement. Some commonly used approaches need no sensor at all; however, these methods tend to overestimate the height reached by the subjects. There are also novel systems using different kind of sensors like force-sensitive resistors, capacitive sensors, and inertial measurement units, among others, to achieve more accurate measurements. Objective The objective of this study is twofold. The first objective is to validate the functioning of a developed low-cost system able to measure vertical jump height. The second objective is to assess the effects on obtained measurements when the sampling frequency of the system is modified. Methods The system developed in this study consists of a matrix of force-sensitive resistor sensors embedded in a mat with electronics that allow a full scan of the mat. This mat detects pressure exerted on it. The system calculates the jump height by using the flight-time formula, and the result is sent through Bluetooth to any mobile device or PC. Two different experiments were performed. In the first experiment, a total of 38 volunteers participated with the objective of validating the performance of the system against a high-speed camera used as reference (120 fps). In the second experiment, a total of 15 volunteers participated. Raw data were obtained in order to assess the effects of different sampling frequencies on the performance of the system with the same reference device. Different sampling frequencies were obtained by performing offline downsampling of the raw data. In both experiments, countermovement jump and countermovement jump with arm swing techniques were performed. Results In the first experiment an overall mean relative error (MRE) of 1.98% and a mean absolute error of 0.38 cm were obtained. Bland-Altman and correlation analyses were performed, obtaining a coefficient of determination equal to R2=.996. In the second experiment, sampling frequencies of 200 Hz, 100 Hz, and 66.6 Hz show similar performance with MRE below 3%. Slower sampling frequencies show an exponential increase in MRE. On both experiments, when dividing jump trials in different heights reached, a decrease in MRE with higher height trials suggests that the precision of the proposed system increases as height reached increases. Conclusions In the first experiment, we concluded that results between the proposed system and the reference are systematically the same. In the second experiment, the relevance of a sufficiently high sampling frequency is emphasized, especially for jump trials whose height is below 10 cm. For trials with heights above 30 cm, MRE decreases in general for all sampling frequencies, suggesting that at higher heights reached, the impact of high sampling frequencies is lesser.

scholarly journals Lower-Limb Power cannot be Estimated Accurately from Vertical Jump Tests

2013 ◽  
Vol 38 ◽  
pp. 5-13 ◽  
Author(s):  
Jean-François Tessier ◽  
Fabien-A Basset ◽  
Martin Simoneau ◽  
Normand Teasdale
Keyword(s):  
Lower Limb ◽  
Vertical Jump ◽  
Ground Reaction Forces ◽  
Trained Group ◽  
Countermovement Jump ◽  
Predictive Equations ◽  
Jump Test ◽  
Minimal Difference ◽  
Reaction Forces ◽  
Study Power

Abstract The countermovement jump test is often adopted to monitor lower-limb power of an individual. Despite several studies on the validity of this test, there is still a need to determine the minimal difference needed to be confident that a difference in power between two individuals is present or that a true change in the performance of an individual has occurred. In this study, power was measured from ground reaction forces and compared to that obtained from predictive equations for two groups of subjects (67 trained and 20 highly trained individuals). The height of each jump was determined with kinematic techniques. The main outcome is a large discrepancy between power calculated from ground reaction forces and that calculated from predictive equations. For the trained group, the R-square value between power and predicted power was 0.53 and the minimal difference to consider that two individuals were different was 821.7 W. For the highly trained individuals, a much larger R-square value was obtained (0.94). Despite this, the minimal difference to consider that two individuals were different was still large (689.3 W). The large minimal differences obtained raise serious concerns about using countermovement jumps for appraisal and monitoring of lower-limb power of an individual.

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