scholarly journals Does Footwear Influence Countermovement Jump Parameters Used to Assess Performance in Collegiate Basketball Players?

2021 ◽  
Vol 9 (2) ◽  
pp. 14
Author(s):  
Aaron D. Heishman ◽  
Keldon M. Peak ◽  
Bryce D. Daub ◽  
Ryan M. Miller ◽  
Eduardo D.S. Freitas
Keyword(s):  
Repeated Measures ◽  
Performance Outcomes ◽  
Performance Assessments ◽  
Countermovement Jump ◽  
Mean Power ◽  
Basketball Players ◽  
Short And Long Term ◽  
Collegiate Basketball ◽  
Testing Protocols

Background: The countermovement jump (CMJ) is used to monitor short- and long-term changes in neuromuscular performance, where practically relevant alteration may be subtle, requiring detailed and consistent testing protocols to limit error and allow detection of meaningful change. Collegiate basketball players often wear different types of footwear depending upon the training activity, potentially influencing CMJ performance outcomes. Objective: This study evaluated the influence of footwear on key CMJ variables used for routine performance assessments in a cohort of 11 NCAA women’s collegiate basketball players. Method: In a cross-over repeated measures study design, players performed three CMJs in Basketball-, Training-(Trainers), and Olympic Weightlifting (WL) shoes, in a randomized order during one testing session. One-way repeated measures analyses of variance (p ≤ .05) and effect sizes (Cohen’s d) were used to discern differences in CMJ variables among shoe conditions. Results: WL demonstrated greater Eccentric Mean Force (p ≤ .014, d ≥ 0.03) and lower Flight Time:Contraction Time (p ≤ .029, d ≥ 0.31), Jump Height (p ≤ .040, d ≥ 0.32), and Reactive Strength Index-Modified (p ≤ .032, d ≥ 0.40) than both Basketball and Trainers. Additionally, WL exhibited lower Concentric Mean Force (p = .018, d = 0.19), Concentric Mean Power (p = .008, d = 0.29), Eccentric Peak Force (p = .050, d = 0.19), and Flight Time (p = .036, d = 0.31) compared to Trainer. No significant differences and only trivial effects appeared between Basketball and Trainers (p > 0.05, d < 0.1). Conclusion: These findings suggest footwear significantly influences CMJ performance. WL shoes appear to negatively impact CMJ performance; however, Basketball and Trainers appear to exert negligible effects that should allow clinicians and practitioners to feel confident about measurement and data quality when performing short- and long-term CMJ measurements in either Basketball or Trainers.

scholarly journals The Influence of Countermovement Jump Protocol on Reactive Strength Index Modified and Flight Time: Contraction Time in Collegiate Basketball Players

Sports ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 37 ◽  
Author(s):  
Aaron Heishman ◽  
Brady Brown ◽  
Bryce Daub ◽  
Ryan Miller ◽  
Eduardo Freitas ◽  
...  
Keyword(s):  
Force Plate ◽  
Flight Time ◽  
Contraction Time ◽  
Strength Index ◽  
Countermovement Jump ◽  
Basketball Players ◽  
Arm Swing ◽  
Collegiate Basketball ◽  
Positive Correlations ◽  
The Relationship

The purpose of the present investigation was to evaluate differences in Reactive Strength Index Modified (RSIMod) and Flight Time to Contraction Time Ratio (FT:CT) during the countermovement jump (CMJ) performed without the arm swing (CMJNAS) compared to the CMJ with the arm swing (CMJAS), while exploring the relationship within each variable between jump protocols. A secondary purpose sought to explore the relationship between RSIMod and FT:CT during both jump protocols. Twenty-two collegiate basketball players performed both three CMJNAS and three CMJAS on a force plate, during two separate testing sessions. RSIMod was calculated by the flight-time (RSIModFT) and impulse-momentum methods (RSIModIMP). CMJ variables were significantly greater during the CMJAS compared to CMJNAS (p < 0.001). There were large to very large correlations within each variable between the CMJAS and CMJNAS. There were significant positive correlations among RSIModFT, RSIModIMP, and FT:CT during both the CMJAS (r ≥ 0.864, p < 0.001) and CMJNAS (r ≥ 0.960, p < 0.001). These findings identify an increase in RSIMod or FT:CT during the CMJAS, that may provide independent information from the CMJNAS. In addition, either RSIMod or FT:CT may be utilized to monitor changes in performance, but simultaneous inclusion may be unnecessary.

scholarly journals Enhancement of Countermovement Jump Performance Using a Heavy Load with Velocity-Loss Repetition Control in Female Volleyball Players

2021 ◽  
Vol 18 (21) ◽  
pp. 11530
Author(s):  
Michal Krzysztofik ◽  
Rafal Kalinowski ◽  
Robert Trybulski ◽  
Aleksandra Filip-Stachnik ◽  
Petr Stastny
Keyword(s):  
Body Mass ◽  
Repeated Measures ◽  
Performance Enhancement ◽  
Countermovement Jump ◽  
Mean Power ◽  
Mean Velocity ◽  
Heavy Load ◽  
Jump Performance ◽  
Volleyball Players ◽  
Post Hoc

Although velocity control in resistance training is widely studied, its utilization in eliciting post-activation performance enhancement (PAPE) responses receives little attention. Therefore, this study aimed to evaluate the effectiveness of heavy-loaded barbell squats (BS) with velocity loss control conditioning activity (CA) on PAPE in subsequent countermovement jump (CMJ) performance. Sixteen resistance-trained female volleyball players participated in this study (age: 24 ± 5 yrs.; body mass: 63.5 ± 5.2 kg; height: 170 ± 6 cm; relative BS one-repetition maximum (1RM): 1.45 ± 0.19 kg/body mass). Each participant performed two different conditions: a set of the BS at 80% 1 RM with repetitions performed until a mean velocity loss of 10% as the CA or a control condition without CA (CNTRL). To assess changes in jump height (JH) and relative mean power output (MP), the CMJ was performed 5 min before and throughout the 10 min after the CA. The two-way analysis of variance with repeated measures showed a significant main effect of condition (p = 0.008; η2 = 0.387) and time (p < 0.0001; η2 = 0.257) for JH. The post hoc test showed a significant decrease in the 10th min in comparison to the value from baseline (p < 0.006) for the CNTRL condition. For the MP, a significant interaction (p = 0.045; η2 = 0.138) was found. The post hoc test showed a significant decrease in the 10th min in comparison to the values from baseline (p < 0.006) for the CNTRL condition. No significant differences were found between all of the time points and the baseline value for the CA condition. The CA used in the current study fails to enhance subsequent countermovement jump performance in female volleyball players. However, the individual analysis showed that 9 out of the 16 participants (56%) responded positively to the applied CA, suggesting that the PAPE effect may be individually dependent and should be carefully verified before implementation in a training program.

scholarly journals Countermovement Jump Inter-Limb Asymmetries in Collegiate Basketball Players

Sports ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 103 ◽  
Author(s):  
Aaron Heishman ◽  
Bryce Daub ◽  
Ryan Miller ◽  
Brady Brown ◽  
Eduardo Freitas ◽  
...  
Keyword(s):  
Injury Risk ◽  
Force Plate ◽  
Return To Play ◽  
Countermovement Jump ◽  
Basketball Players ◽  
Arm Swing ◽  
Force Development ◽  
Collegiate Basketball ◽  
Limb Asymmetry ◽  
Absolute Reliability

The purpose of the present study was to establish the intrasession and intersession reliability of variables obtained from a force plate that was used to quantitate lower extremity inter-limb asymmetry during the bilateral countermovement jump (CMJ). Secondarily, a comparison was performed to determine the influence of the jump protocol CMJ with or without an arm swing (CMJ AS and CMJ NAS, respectively) on inter-limb asymmetries. Twenty-two collegiate basketball players performed three CMJ AS and three CMJ NAS on dual force platforms during two separate testing sessions. A majority of variables met the acceptable criterion of intersession and intrasession relative reliability (ICC > 0.700), while fewer than half met standards established for absolute reliability (CV < 10%). CMJ protocol appeared to influence asymmetries; Concentric Impulse-100 ms, Eccentric Braking Rate of Force Development, Eccentric Deceleration, and Force at Zero velocity were significantly different between jumping conditions (CMJAS versus CMJ NAS; p < 0.05). The present data establish the reliability and smallest worthwhile change of inter-limb asymmetries during the CMJ, while also identifying the influence of CMJ protocol on inter-limb asymmetries, which can be useful to practitioners and clinicians in order to effectively monitor changes associated with performance, injury risk, and return-to-play strategies.

scholarly journals Short- and long-term effects of using shooting straps on free-throw accuracy of young female basketball players

Kinesiology ◽  
2017 ◽  
Vol 49 (2) ◽  
pp. 225-234 ◽  
Author(s):  
Miguel-Ángel Gómez ◽  
Jaime Sampaio
Keyword(s):  
Basketball Player ◽  
Control Group ◽  
Long Term Effects ◽  
Basketball Players ◽  
Intervention Training ◽  
Free Throw ◽  
Short And Long Term ◽  
One Year ◽  
Experimental Group

This study identified the short- and long-term effects of using a shooting strap on the accuracy of freethrows performed by U15 female basketball players during training and competition. Thirty six female<br>basketball player volunteers (aged 14.3±0.5 years) from the Lithuanian Schoolchildren Basketball League were randomly assigned to either an experimental or control group. The experimental group used a shooting strap that immobilized movements of the supporting hand while shooting. The control group performed freethrows without any training aid. Learning and transfer of performance was assessed before and after the intervention training sessions (4-week intervention program applied 4 times per week), and on a retention test after one year. Results showed that: (a) free-throw accuracy was higher after one month and after one year of intervention than before the intervention training program in both practice and competition; (b) the experimental group scored better in practice and competition than the control group after one month and one year of the intervention; and (c) free-throw accuracy was higher during training sessions than during&nbsp;competition. The identified short-term and long-term improvements in free-throw shooting accuracy support the usage of shooting straps. The use of shooting straps and external assisting devices might allow adjusting programs of training to provide fluent free-throw accuracy progresses from youth to senior categories.

The Effects of Retesting on the Mechanical Properties of Brain Tissue

2013 ◽  
Author(s):  
A. Rezaei ◽  
M. Salimi Jazi ◽  
G. Karami ◽  
M. Ziejewski
Keyword(s):  
Mechanical Properties ◽  
Brain Tissue ◽  
Relaxation Times ◽  
Human Brain Tissue ◽  
Relaxation Functions ◽  
Before And After ◽  
Short And Long Term ◽  
Tissue Characteristics ◽  
Testing Protocols

Traumatic brain injury (TBI) is one of the most important problems in biomechanical engineering, and there have been many experiments conducted in order to characterize the mechanical properties of brain tissue. However, obtaining fresh human brain tissue is difficult, if not impossible. Also, the sample preparation and testing protocols must be carried out with great delicacy because brain tissue is very soft and vulnerable to being deformed under a very small amount of load. Most importantly, according to several researchers, each sample must be tested only one time as the tissue may be damaged and its characteristics subsequently changed. This paper is intended to examine the amount of decay that can happen in material characteristics due to retesting. A stress relaxation test is conducted on the same samples of the swine brain tissue multiple times in small and large deformations. The mechanical properties of the substance are calculated before and after retesting, and the constants of the tissue, as mechanical characteristics, are determined and compared. Short- and long-term moduli, relaxation times and relaxation functions are calculated and compared to understand how much they decay after repeating the experiments. The results show that retesting does not significantly change the elastic part of the tissue characteristics, but the viscous behavior shows a relatively sizeable change. The ability to account for the material decay of the samples due to repetition of the experiments results in the need for fewer samples and less preparation time and effort.

CSR portfolio characteristics and performance outcomes: examining the impacts of CSR portfolio diversity and dynamism

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kyle Turner ◽  
Craig A. Turner ◽  
William H. Heise
Keyword(s):  
Firm Performance ◽  
Dynamic Range ◽  
Performance Outcomes ◽  
Short Term ◽  
Content Type ◽  
Short And Long Term ◽  
Long Term Performance ◽  
Term Performance ◽  
The Relationship

Purpose The purpose of this paper is to introduce and test a portfolio view of a firm’s corporate social responsibility (CSR) activities. Drawing from stakeholder theory and the dynamic capabilities literature, the authors introduce CSR portfolio diversity and dynamism as key portfolio characteristics that have differential impacts across short- and long-term performance contexts. Design/methodology/approach The study draws from the Kinder, Lydenberg and Domini database to examine CSR portfolio diversity and dynamism across seven dimensions of CSR activities. The authors test the direct and indirect relationships between CSR portfolio characteristics and both short- and long-term performance outcomes to assess the opportunities and challenges associated with managing a diverse and dynamic CSR portfolio. Findings The findings suggest that a diverse portfolio of CSR activities positively impacts long-term performance; however, CSR portfolio diversity yields negative performance outcomes in the short-term. The authors also find that CSR portfolio dynamism moderates the relationship between CSR level and firm performance, such that a dynamic portfolio of CSR positively moderates the relationship between a firm’s CSR level and long-term performance; however, it negatively moderates the relationship between CSR level and short-term performance. Originality/value This study integrates insights from the literature that examine the independent effects of individual CSR activities and the broader perspective that assesses the aggregated summation of CSR activities in relation to firm performance. By taking a portfolio perspective, the present study provides a unique integration of these two research streams to examine the performance implications of engaging in a diverse and dynamic range of CSR activities.

scholarly journals Biomechanical Analysis of the Jump Shot in Basketball

2014 ◽  
Vol 42 (1) ◽  
pp. 73-79 ◽  
Author(s):  
Artur Struzik ◽  
Bogdan Pietraszewski ◽  
Jerzy Zawadzki
Keyword(s):  
Peak Power ◽  
High Performance ◽  
Force Plate ◽  
Lower Limbs ◽  
Biomechanical Analysis ◽  
Countermovement Jump ◽  
Mean Power ◽  
Basketball Players ◽  
Arm Swing ◽  
High Level

Abstract Basketball players usually score points during the game using the jump shot. For this reason, the jump shot is considered to be the most important element of technique in basketball and requires a high level of performance. The aim of this study was to compare the biomechanical characteristics of the lower limbs during a jump shot without the ball and a countermovement jump without an arm swing. The differences between variables provide information about the potential that an athlete can utilise during a game when performing a jump shot. The study was conducted among 20 second-league basketball players by means of a Kistler force plate and the BTS SMART system for motion analysis. The variables measured included the take-off time, mean power, peak power, relative mean power, jump height, maximum landing force and calculated impact ratio. Surprisingly, more advantageous variables were found for the jump shot. This finding suggests a very high performance level in the jump shot in the studied group and a maximum utilisation of their motor abilities. Both types of jumps were characterised by high mean and peak power values and average heights. The high forces at landing, which result in considerable impact ratios, may have prompted the studied group to land softly. Use of the countermovement jump without an arm swing is recommended to assess and predict the progression of player’s jumping ability

scholarly journals Does Footwear Influence Countermovement Jump Parameters Used To Monitor Performance In Collegiate Basketball Players?

2021 ◽  
Vol 53 (8S) ◽  
pp. 42-43
Author(s):  
Keldon Peak ◽  
Aaron Heishman ◽  
Bryce Daub ◽  
Ryan Miller ◽  
Eduardo Freitas ◽  
...  
Keyword(s):  
Countermovement Jump ◽  
Basketball Players ◽  
Collegiate Basketball

scholarly journals Short- and Long-Term Effects of DBS on Gait in Parkinson's Disease

2021 ◽  
Vol 12 ◽  
Author(s):  
Hana Brozova ◽  
Isabelle Barnaure ◽  
Evzen Ruzicka ◽  
Jan Stochl ◽  
Ron Alterman ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Repeated Measures ◽  
Rating Scale ◽  
Long Term Effects ◽  
Short Term ◽  
Short And Long Term ◽  
Mean Time ◽  
Stn Dbs

The aim was to compare the short and long-term effects of subthalamic nucleus (STN) deep brain stimulation (DBS) on gait dysfunction and other cardinal symptoms of Parkinson's disease (PD). Two groups of patients were studied. The first group (short-term DBS, n = 8) included patients recently implanted with STN DBS (mean time since DBS 15.8 months, mean age 58.8 years, PD duration 13 years); the second group (long-term DBS, n = 10) included patients with at least 5 years of DBS therapy (mean time since DBS 67.6 months, mean age 61.7 years, PD duration 17.1 years). Both groups were examined using the Unified Parkinson's Disease Rating Scale (UPDRS) and Gait and Balance scale (GABS) during four stimulation/medication states (ON/OFF; OFF/OFF; OFF/ON; ON/ON). Data were analyzed using repeated measures ANOVA with time since implantation (years) between groups and medication or DBS effect (ON, OFF) within groups. In the short-term DBS group, stimulation improved all UPDRS subscores similar to dopaminergic medications. In particular, average gait improvement was over 40% (p = 0.01), as measured by the UPDRS item 29 and GABS II. In the long-term DBS group, stimulation consistently improved all clinical subscores with the exception of gait and postural instability. In these patients, the effect of levodopa on gait was partially preserved. Short-term improvement of gait abnormalities appears to significantly decline after 5 years of STN DBS in PD patients, while effectiveness for other symptoms remains stable. Progressive non-dopaminergic (non-DBS responsive) mechanisms or deleterious effects of high frequency STN stimulation on gait function may play a role.

Effects of Increased Muscle Strength and Muscle Mass on Endurance-Cycling Performance

2016 ◽  
Vol 11 (3) ◽  
pp. 283-289 ◽  
Author(s):  
Iñigo Mujika ◽  
Bent R. Rønnestad ◽  
David T. Martin
Keyword(s):  
Resistance Training ◽  
Muscle Mass ◽  
Endurance Performance ◽  
Cycling Performance ◽  
Lower Body ◽  
Mean Power ◽  
Endurance Cycling ◽  
Efficient Type ◽  
Short And Long Term

Despite early and ongoing debate among athletes, coaches, and sport scientists, it is likely that resistance training for endurance cyclists can be tolerated, promotes desired adaptations that support training, and can directly improve performance. Lower-body heavy strength training performed in addition to endurance-cycling training can improve both short- and long-term endurance performance. Strength-maintenance training is essential to retain strength gains during the competition season. Competitive female cyclists with greater lower-body lean mass (LBLM) tend to have ~4–9% higher maximum mean power per kg LBLM over 1 s to 10 min. Such relationships enable optimal body composition to be modeled. Resistance training off the bike may be particularly useful for modifying LBLM, whereas more cycling-specific training strategies like eccentric cycling and single-leg cycling with a counterweight have not been thoughtfully investigated in well-trained cyclists. Potential mechanisms for improved endurance include postponed activation of less efficient type II muscle fibers, conversion of type IIX fibers into more fatigue-resistant IIa fibers, and increased muscle mass and rate of force development.

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