scholarly journals Kinematic and Neuromuscular Measures of Intensity During Drop Jumps in Female Volleyball Players

2021 ◽  
Vol 12 ◽  
Author(s):  
Maximiliano Torres-Banduc ◽  
Rodrigo Ramirez-Campillo ◽  
David Cristobal Andrade ◽  
Julio Calleja-González ◽  
Pantelis Theo Nikolaidis ◽  
...  
Keyword(s):  
Contact Time ◽  
Biceps Femoris ◽  
Cross Sectional Study ◽  
Vastus Medialis ◽  
Jump Height ◽  
Strength Index ◽  
Maximal Voluntary Isometric Contraction ◽  
Cross Sectional ◽  
Gastrocnemius Medialis ◽  
Volleyball Players

The aim of this study was to assess drop jump (DJ) performance variables (jump height, contact time, and reactive strength index) concomitant to surface electromyography (sEMG) of lower limb muscles during DJs from different drop heights (intensities). The eccentric and concentric phase sEMG from the gastrocnemius medialis, biceps femoris, and vastus medialis muscles were assessed during all tests, with sEMG activity normalized to maximal voluntary isometric contraction (MVIC). In a cross-sectional, study, 10 amateur female volleyball players (age 22.1 ± 1.8 years; body mass 72.9 ± 15.2 kg; height 1.70 ± 0.08 m) completed DJs from six heights [15–90 cm (DJ15 to DJ90)]. During DJs there was no jump-target box to rebound on to. Results of one-way analysis of variance (ANOVA) showed that the jump height, contact time, and reactive strength index were not significantly (p > 0.05) different between drop heights. Mean biceps femoris eccentric and concentric sEMG ranged from 27 to 50%, although without significant differences between drop heights. Mean gastrocnemius medialis eccentric and concentric sEMG remained relatively constant (∼60–80% MVIC) across DJs heights, although eccentric values reached 90–120% MVIC from DJ75 to DJ90. Mean variations of ∼50–100% MVIC for eccentric and ∼50–70% MVIC for concentric sEMG activations were observed in the vastus medialis across DJs heights. The biceps femoris eccentric/concentric sEMG ratio during DJ45 (i.e., 1.0) was lower (p = 0.03) compared to the ratio observed after DJ90 (i.e., 3.2). The gastrocnemius medialis and vastus medialis eccentric/concentric sEMG ratio were not significantly different between drop heights. In conclusion, jumping performance and most neuromuscular markers were not sensitive to DJ height (intensity) in amateur female volleyball athletes.

scholarly journals Evaluation of Lower Limb Muscle Electromyographic Activity during 400 m Indoor Sprinting among Elite Female Athletes: A Cross-Sectional Study

2021 ◽  
Vol 18 (24) ◽  
pp. 13177
Author(s):  
Przemysław Pietraszewski ◽  
Artur Gołaś ◽  
Michał Krzysztofik ◽  
Marta Śrutwa ◽  
Adam Zając
Keyword(s):  
Lower Limb ◽  
Vastus Lateralis ◽  
Gluteus Maximus ◽  
Biceps Femoris ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Cross Sectional ◽  
Gastrocnemius Medialis ◽  
Lower Limb Muscles ◽  
Semg Signals

The purpose of this cross-sectional study was to analyze changes in normalized surface electromyography (sEMG) signals for the gastrocnemius medialis, biceps femoris, gluteus maximus, tibialis anterior, and vastus lateralis muscles occurring during a 400 m indoor sprint between subsequent curved sections of the track. Ten well-trained female sprinters (age: 21 ± 4 years; body mass: 47 ± 5 kg; body height: 161 ± 7 cm; 400 m personal best: 52.4 ± 1.1 s) performed an all-out 400 m indoor sprint. Normalized sEMG signals were recorded bilaterally from the selected lower limb muscles. The two-way ANOVA (curve × side) revealed no statistically significant interaction. However, the main effect analysis showed that normalized sEMG signals significantly increased in subsequent curves run for all the studied muscles: gastrocnemius medialis (p = 0.003), biceps femoris (p < 0.0001), gluteus maximus (p = 0.044), tibialis anterior (p = 0.001), and vastus lateralis (p = 0.023), but differences between limbs were significant only for the gastrocnemius medialis (p = 0.012). The results suggest that the normalized sEMG signals for the lower limb muscles increased in successive curves during the 400 m indoor sprint. Moreover, the gastrocnemius medialis of the inner leg is highly activated while running curves; therefore, it should be properly prepared for high demands, and attention should be paid to the possibility of the occurrence of a negative adaptation, such as asymmetries.

Male Volleyball Players’ Self-Esteem in the Context of Volleyball Competition

2021 ◽  
Vol 1 (2) ◽  
pp. 1-6
Author(s):  
Shireen Bhatti ◽  
Muhammad Asif Shaikh
Keyword(s):  
Focus Group ◽  
Focus Group Discussion ◽  
Urban Areas ◽  
Group Discussion ◽  
Performance Anxiety ◽  
Age Groups ◽  
Self Esteem ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Volleyball Players

The goal of this study was to evaluate the competition anxiety and self-esteem among male volleyball players. Cross sectional study design, followed by qualitative investigation, was used in the current study. The participants in this study were 20 male volleyball players from the urban areas of the Province of Sindh Public Boys College. Both volleyball players at college and provincial level participated in the volleyball game. The player was between 16 and 20 years of age. Two questionnaires were used in the current study: (1) the Sports Performance Anxiety Test was used to consider performance anxiety and (2) the self-esteem of Rosenberg was used to describe self-esteem and (3) the focus group discussion. The results of the current study showed fluctuation in self-esteem level and anxiety level among players of different age groups regarding participation in volleyball competition. In Focus group discussion, regarding low self-esteem and higher competition anxiety, participants are of the view that low self-esteem and increase in anxiety undoubtedly have a greater negative effect on the team's psychology. Negative attitudes towards oneself, people's evaluation or opinion, fear of failure, risk of competitive climate, fear of adversary, low level of efforts, nervousness, negative feedback, rejection, criticism, nervousness, coach, team mates and high expectations of the audience are the factors that can contribute to low self-esteem and high anxiety. The study proposed some recommendations for future researchers.

scholarly journals Association between the levels of physical activity and plantar pressure in 6-14-year-old children

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8551 ◽  
Author(s):  
Lovro Štefan ◽  
Mario Kasović ◽  
Martin Zvonar
Keyword(s):  
Physical Activity ◽  
Plantar Pressure ◽  
Contact Time ◽  
Cross Sectional Study ◽  
Linear Regression Models ◽  
Older Children ◽  
Cross Sectional ◽  
Time Integral ◽  
Pressure Time ◽  
The Right

Background The main purpose of the study was to determine whether lower levels of physical activity were associated with higher plantar pressure generated under each foot. Methods In this cross-sectional study, we recruited 641 children aged 6–14 years (agemean ± SD = 9.7  ± 2.4 years; heightmean ± SD = 143.6  ± 15.3 cm, weightmean ± SD = 37.6  ± 13.4 kg; body-mass indexmean ± SD = 17.6  ± 3.2 kg/m2; 44.2% girls). We used EMED –XL pressure platform to measure force time integral, pressure-time integral, contact-time and contact area, peak plantar pressure and mean plantar pressure of the right and the left foot during the gait analysis. The level of physical activity was measured by using The Physical Activity Questionnaire for Older Children (PAQ–C). The associations were calculated by using generalized estimating equations with linear regression models. Results Lower levels of physical activity were associated with higher force- and pressure-time integrals, longer contact time and higher peak and mean plantar pressures in both feet. Conclusion Our study shows that the level of physical activity is strongly and inversely associated with plantar pressure in a sample of 6–14 year olds.

scholarly journals The Influence of Recruitment Age and Anthropometric and Physical Characteristics on the Development Pathway of English Academy Football Players

2020 ◽  
pp. 1-9
Author(s):  
Mark R. Noon ◽  
Emma L.J. Eyre ◽  
Matthew Ellis ◽  
Tony D. Myers ◽  
Rhys O. Morris ◽  
...  
Keyword(s):  
Cross Sectional Study ◽  
Physical Characteristics ◽  
Bayesian Regression ◽  
Football Players ◽  
Jump Height ◽  
Countermovement Jump ◽  
Cross Sectional ◽  
Male Youth ◽  
Development Pathway ◽  
Key Indicator

Purpose: To investigate the influence of recruitment age on retention and release across the development pathway and to explore the influence of anthropometric and physical characteristics on retention and release at different ages throughout the development pathway and the likelihood of obtaining a professional contract. Methods: Following receipt of ethics approval, a cross-sectional study tracking 4 cohorts of players over 5 years assessed 76 male youth football players (11–16 y) from an English football academy on 3 occasions annually in anthropometry, countermovement jump height, and linear (30 and 15 m) and multidirectional sprint time. Players were categorized based on their start and release date. Results: Starting early (ie, before U12) in an academy was a key indicator of obtaining a professional contract, representing 87% of the players signed. Bayesian regression models suggest that the majority of differences in physical characteristics between players that were released and retained are trivial, small, and/or uncertain. Players who attained a professional contract at 18 had slower 15- and 30-m sprint times at U13 to U15 (P > 0 = .87–.99), slower multidirectional sprint times at U14 (P > 0 = .99), and lower countermovement jump height at U13 to U16 (P > 0 = .88–.99) compared with players who did not gain a contract. Conclusion: Players recruited early have an increased likelihood of gaining a professional contract. Physical assessments lack utility when used in isolation as a talent-identification tool.

scholarly journals Relationship Between Isokinetic Knee Strength and Single-Leg Drop Jump Performance 9 Months After ACL Reconstruction

2022 ◽  
Vol 10 (1) ◽  
pp. 232596712110638
Author(s):  
N.M. Nuala Crotty ◽  
Katherine A.J. Daniels ◽  
Ciaran McFadden ◽  
Niall Cafferkey ◽  
Enda King
Keyword(s):  
Contact Time ◽  
Cruciate Ligament ◽  
Knee Extensor ◽  
Jump Height ◽  
Drop Jump ◽  
Linear Regression Models ◽  
Level Of Evidence ◽  
Cross Sectional ◽  
Knee Strength ◽  
The Relationship

Background: Deficits in knee strength after anterior cruciate ligament reconstruction (ACLR) surgery are common. Deficits in the single-leg drop jump (SLDJ), a test of plyometric ability, are also found. Purpose: To examine the relationship between isokinetic knee strength, SLDJ performance, and self-reported knee function 9 months after ACLR. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Knee isokinetic peak torque, SLDJ jump height, contact time, and reactive strength index (RSI), as well as International Knee Documentation Committee (IKDC) scores were assessed in 116 male, field-sport athletes at 9.2 months after ACLR. SLDJ testing took place in a 3-dimensional biomechanics laboratory. Linear regression models were used to analyze the relationship between the variables. Results: A significant relationship was found between ACLR-limb isokinetic knee extensor strength and SLDJ jump height ( P < .001, r 2 = 0.29) and RSI ( P < .001, r 2 = 0.33), and between ACLR-limb isokinetic knee flexor strength and SLDJ jump height ( P < .001, r 2 = 0.12) and RSI ( P < .001, r 2 = 0.15). A significant positive relationship was also found between knee extensor asymmetry and SLDJ jump height asymmetry ( P < .001, r 2 = 0.27) and SLDJ reactive strength asymmetry ( P < .001, r 2 = 0.18). Combined ACLR-limb jump height and contact time best predicted IKDC scores ( P < .001, r 2 = 0.12). Conclusion: Isokinetic knee extension strength explained approximately 30% of SLDJ performance, with a much weaker relationship between knee flexion strength and SLDJ performance. Isokinetic strength and SLDJ performance were weak predictors of variation in IKDC scores.

scholarly journals Spiking Kinematics in Volleyball Players With Shoulder Pain

2019 ◽  
Vol 54 (1) ◽  
pp. 90-98 ◽  
Author(s):  
Yi-Fen Shih ◽  
Yuan-Ching Wang
Keyword(s):  
Internal Rotation ◽  
Shoulder Pain ◽  
Glenohumeral Joint ◽  
Tracking System ◽  
Cross Sectional Study ◽  
Control Group ◽  
Cross Sectional ◽  
Volleyball Players ◽  
Ball Contact ◽  
Posterior Tilt

Context Spiking is one of the most frequently used scoring techniques in volleyball games, and around 80% of shoulder pain in volleyball players is linked with the spiking movement. Objective To investigate the differences in glenohumeral joint, scapular, and trunk movements during the spiking motion between volleyball players with and those without shoulder pain. Design Cross-sectional study. Setting University laboratory. Patients or Other Participants Twenty amateur volleyball players with shoulder pain (age = 21.8 ± 1.79 years, with an average of 4.0 ± 0.92 years of volleyball experience and 6.0 ± 3.51 months of shoulder pain) and 20 sex-, age-, and experience-matched control participants. Main Outcome Measure(s) The 3-dimensional kinematics of the shoulder joint, scapula, and trunk during spiking were assessed using an electromagnetic tracking system. Results Compared with the control group, individuals with shoulder pain demonstrated less scapular posterior tilt (P = .041) and more glenohumeral horizontal abduction (P = .008) and scapular internal rotation (P = .02) at ball contact when performing the cross-body spike. Conclusions The decrease in scapular posterior tilt, along with increased glenohumeral horizontal abduction and scapular internal rotation, was associated with shoulder pain in university volleyball players. These changes should be addressed in the training and treatment of young volleyball players.

Risk factors for patellar tendinopathy in volleyball players: a cross-sectional study

2011 ◽  
Vol 45 (6) ◽  
pp. 536-536
Author(s):  
H. van der Worp ◽  
M. van Ark ◽  
J. Zwerver ◽  
I. van den Akker-Scheek
Keyword(s):  
Risk Factors ◽  
Cross Sectional Study ◽  
Patellar Tendinopathy ◽  
Sectional Study ◽  
Cross Sectional ◽  
Volleyball Players

Achilles Tendon Properties of Minimalist and Traditionally Shod Runners

2017 ◽  
Vol 26 (2) ◽  
pp. 159-164 ◽  
Author(s):  
Katherine Histen ◽  
Julia Arntsen ◽  
Lauren L’Hereux ◽  
James Heeren ◽  
Benjamin Wicki ◽  
...  
Keyword(s):  
Outcome Measures ◽  
Cross Sectional Study ◽  
Training Experience ◽  
Laboratory Assessment ◽  
Maximal Voluntary Isometric Contraction ◽  
Cross Sectional ◽  
Mechanical Adaptation ◽  
Trained Runners ◽  
Plantar Flexor Muscles ◽  
Tendon Properties

Context:Tendon adapts to load through alterations in its composition and mechanical properties. Mechanical adaptation to increased load often involves increases in cross-sectional area (CSA), stiffness, and modulus. Runners exhibit these adaptations.Objective:To determine if runners wearing minimalist shoes had larger and stiffer Achilles tendons (AT) than traditionally shod runners.Design:Cross-sectional study of well-trained, traditionally and minimally shod runners.Setting:Laboratory assessment of trained runners.Participants: 23 men (11 traditional, 12 minimalist) and 8 women (6 traditional, 2 minimalist). Runners wearing minimalist shoes had 4.2 ± 1.6 y of training experience in minimalist shoes.Main Outcome Measures:The authors used diagnostic ultrasound and isokinetic dynamometry to generate a force-elongation curve and its derivatives.Results: Minimalist runners had a greater CSA: mean difference (MD) = 9.2 mm2, stiffness (MD = 268.1 N/mm), and modulus (MD = 202.9 MPa). ATs of minimalist runners experienced greater stress (MD 8.6 N/mm2) during maximal voluntary isometric contraction of the plantar-flexor muscles due to greater force of contraction (MD 798.9 N).Conclusion:The AT in minimalist runners adapts by increasing size, stiffness, and modulus, which is consistent with our understanding of mechanical adaptation of tendon to increased loading. Increased stress to the AT likely requires a slow transition to minimalist running to allow the AT to adapt without evidence of injury.

scholarly journals Relationship between Running Spatiotemporal Kinematics and Muscle Performance in Well-Trained Youth Female Athletes. A Cross-Sectional Study

2021 ◽  
Vol 18 (16) ◽  
pp. 8869
Author(s):  
Alejandro Castillo-Domínguez ◽  
Jerónimo García-Romero ◽  
Joaquín Páez-Moguer ◽  
Tomás Ponce-García ◽  
Miguel Medina-Alcántara ◽  
...  
Keyword(s):  
Step Length ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Strength Index ◽  
Countermovement Jump ◽  
Step Frequency ◽  
Cross Sectional ◽  
Performance Variables ◽  
Neuromuscular Performance ◽  
Spatiotemporal Parameters

The purpose of this cross-sectional study was to analyse the relationship of neuromuscular performance and spatiotemporal parameters in 18 adolescent distance athletes (age, 15.5 ± 1.1 years). Using the OptoGait system, the power, rhythm, reactive strength index, jump flying time, and jump height of the squat jump, countermovement jump, and eight maximal hoppings test (HT8max) and the contact time (CT), flying time (FT), step frequency, stride angle, and step length of running at different speeds were measured. Maturity offset was determined based on anthropometric variables. Analysis of variance (ANOVA) of repeated measurements showed a reduction in CT (p < 0.000) and an increase in step frequency, step length, and stride angle (p < 0.001), as the velocity increased. The HT8max test showed significant correlations with very large effect sizes between neuromuscular performance variables (reactive strength index, power, jump flying time, jump height, and rhythm) and both step frequency and step length. Multiple linear regression found this relationship after adjusting spatiotemporal parameters with neuromuscular performance variables. Some variables of neuromuscular performance, mainly in reactive tests, were the predictors of spatiotemporal parameters (CT, FT, stride angle, and VO). Rhythm and jump flying time in the HT8max test and power in the countermovement jump test are parameters that can predict variables associated with running biomechanics, such as VO, CT, FT, and stride angle.

Sign in / Sign up

Export Citation Format

Share Document