scholarly journals Biomechanical Determinants of the Reactive Strength Index During Drop Jumps

2018 ◽  
Vol 13 (1) ◽  
pp. 44-49 ◽  
Author(s):  
Kristof Kipp ◽  
Michael T. Kiely ◽  
Matthew D. Giordanelli ◽  
Philip J. Malloy ◽  
Christopher F. Geiser
Keyword(s):  
Ncaa Division I ◽  
Division I ◽  
Drop Height ◽  
Strength Index ◽  
Basketball Players ◽  
Vertical Stiffness ◽  
Biomechanical Behavior ◽  
Drop Jumps ◽  
Initial Drop ◽  
Highly Correlated

The Reactive Strength Index (RSI) is often used to quantify drop-jump (DJ) performance; however, not much is known about its biomechanical determinants. The purpose of this study was to investigate the correlations between the RSI and several biomechanical variables calculated from DJ performed with different initial drop heights. Twelve male NCAA Division I basketball players performed DJs from drop heights of 30, 45, and 60 cm. Force plates were used to calculate DJ performance parameters (ie, DJ height, contact time, and RSI) and DJ biomechanical variables (ie, vertical stiffness and eccentric/concentric energetics). Regression analyses were used to assess the correlations between variables at each drop height, and ANOVAs were used to assess the differences of all variables across drop heights. Follow-up analyses used 2 neural networks to determine if DJ performance and biomechanical data could accurately classify DJ trials by drop-height condition. Vertical-stiffness values were significantly correlated with RSI at each height but did not change across drop heights. Surprisingly, the RSI and other DJ parameters also did not vary across drop height, which resulted in the inability of these variables to accurately classify DJ trials. Given that vertical stiffness did not change across drop height and was highly correlated with RSI at each height, the RSI appears to reflect biomechanical behavior related to vertical stiffness during DJ. However, the inability of the RSI to accurately classify drop-height condition questions the use of RSI profiles established from DJs from different heights.

scholarly journals Effect of Achilles Tendon Repair on Performance Outcomes After Return to Play in National Collegiate Athletic Association Division I Basketball Athletes

2021 ◽  
Vol 9 (6) ◽  
pp. 232596712110152
Author(s):  
Rafael Sanchez ◽  
Blake H. Hodgens ◽  
Joseph S. Geller ◽  
Samuel Huntley ◽  
Jonathan Kaplan ◽  
...  
Keyword(s):  
Ncaa Division I ◽  
National Collegiate Athletic Association ◽  
Performance Metrics ◽  
Female Athletes ◽  
Surgical Repair ◽  
National Basketball Association ◽  
Division I ◽  
Return To Play ◽  
Basketball Players ◽  
Significant Drop

Background: Achilles tendon (AT) ruptures are devastating injuries that are highly prevalent among athletes. Despite our understanding of the effect of AT rupture and in particular its relationship to basketball, no study has examined the effects of AT rupture and repair on performance metrics in collegiate basketball players. Purpose: To evaluate the effect of AT rupture and subsequent surgical repair on performance metrics in National Collegiate Athletic Association (NCAA) Division I basketball players who return to play after injury. Study Design: Descriptive epidemiology study. Methods: NCAA Division I basketball players who sustained an AT rupture and underwent subsequent surgical repair between 2000 and 2019 were identified by systematically evaluating individual injury reports from databases comprising NCAA career statistics and individual school statistics; 65 male and 41 female players were identified. Athletes were included if they participated in at least one-half of the games of 1 collegiate season before tearing the AT and at least 1 season after operative repair. A total of 50 male and 30 female athletes were included. Each injured athlete was matched to a healthy control by conference, position, starter status at time of injury, class year, and number of games played. Matched controls were healthy players and experienced no significant injuries during their NCAA careers. Results: After AT repair, male athletes had significantly more minutes per game, points per game, and compared with before injury. Total blocks significantly decreased after injury. Female athletes scored significantly more points per game but demonstrated a significantly lower 3-point shooting percentage after return to play. Despite undergoing AT rupture and repair, 14% of male players played in the National Basketball Association, and 20% of injured female athletes played in the Women’s National Basketball Association. Conclusion: After returning to play, men demonstrated a significant drop-off in performance only in regard to total blocks. Female athletes after AT repair demonstrated a significant improvement in points per game but had a significant drop-off in 3-point shooting percentage.

scholarly journals Assessing Plyometric Ability during Vertical Jumps Performed by Adults and Adolescents

Sports ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 132 ◽  
Author(s):  
Brandon Snyder ◽  
Shawn Munford ◽  
Chris Connaboy ◽  
Hugh Lamont ◽  
Shala Davis ◽  
...  
Keyword(s):  
Contact Time ◽  
Analysis Data ◽  
Adolescent Male ◽  
Ground Contact ◽  
Strength Index ◽  
Basketball Players ◽  
Contact Phase ◽  
Adult Men ◽  
Drop Jumps ◽  
Vertical Jumps

The purpose of this study was to compare different methods for assessing plyometric ability during countermovement (CMJ) and drop jumps (DJ) in a group of adults and adolescents. Ten resistance-trained adult men (age: 22.6 ± 1.6 years) and ten adolescent male basketball players (age: 16.5 ± 0.7 years) performed a CMJ and a DJ from a height of 0.40 m. Jump height (JH), contact time, normalized work (WNORM), and power output (PONORM) during the absorption and propulsion phases were calculated from force platforms and 3-D motion analysis data. Plyometric ability was assessed using the modified reactive strength index (RSIMOD during CMJ) and the reactive strength index (RSI during DJ) as well as three indices using propulsion time, propulsion work (PWI), and propulsion power. Adults jumped significantly higher than adolescents (mean difference [MD]: 0.05 m) while JH (MD: 0.05 m) and ground contact time (MD: 0.29 s) decreased significantly from CMJ to DJ. WNORM (MD: 4.2 J/kg) and PONORM (MD: 24.2 W/kg) during the absorption phase of CMJ were significantly less than these variables during the propulsion phases of the jumps. The reactive strength index variants increased significantly from the CMJ to DJ (MD: 0.23) while all other plyometric indices decreased significantly. Neither RSIMOD nor RSI contributed significantly to the prediction of JH during CMJ and DJ, respectively, while PWI was able to explain ≥68% of the variance in JH. Variants of the reactive strength index do not reflect the changes in mechanical variables during the ground contact phase of CMJ and DJ and may not provide an accurate assessment of plyometric ability during different vertical jumps.

Relationships Of Lower Body Power And Strength For NCAA Division I Men's Collegiate Basketball Players

2011 ◽  
Vol 43 (Suppl 1) ◽  
pp. 398
Author(s):  
Mike Lane ◽  
Andy C. Fry ◽  
Phil M. Gallagher ◽  
J P. Vardiman ◽  
Andrea Hudy ◽  
...  
Keyword(s):  
Ncaa Division I ◽  
Division I ◽  
Lower Body ◽  
Basketball Players ◽  
Collegiate Basketball ◽  
Lower Body Power

A Comparison of Bilateral and Unilateral Drop Jumping Tasks in the Assessment of Vertical Stiffness

2018 ◽  
Vol 34 (3) ◽  
pp. 199-204
Author(s):  
Sean J. Maloney ◽  
Joanna Richards ◽  
Iain M. Fletcher
Keyword(s):  
Coefficient Of Variation ◽  
Center Of Mass ◽  
Reaction Force ◽  
Force Plate ◽  
Drop Height ◽  
Vertical Stiffness ◽  
Drop Jumps ◽  
Left And Right ◽  
Plate System ◽  
Healthy Males

This study sought to compare vertical stiffness during bilateral and unilateral drop jumping. Specifically, the intersession reliabilities and force-deformation profiles associated with each task were to be examined. On 3 occasions, following familiarization, 14 healthy males (age: 22 [2] y; height: 1.77 [0.08] m; and body mass: 73.5 [8.0] kg) performed 3 bilateral, left leg and right leg drop jumps. All jumps were performed from a drop height of 0.18 m on to a dual force plate system. Vertical stiffness was calculated as the ratio of peak ground reaction force (GRF) to the peak center of mass (COM) displacement. Unilateral drop jumping was associated with higher GRF and greater COM displacement (both Ps < .001), but vertical stiffness was not different between tasks when considering individual limbs (P = .98). A coefficient of variation of 14.6% was observed for bilateral vertical stiffness during bilateral drop jumping; values of 6.7% and 7.6% were observed for left and right limb vertical stiffness during unilateral drop jumping. These findings suggest that unilateral drop jumps may exhibit greater reliability than bilateral drop jumps while eliciting similar vertical stiffness. It is also apparent that higher GRFs during unilateral drop jumping are mitigated by increased COM displacement.

Collegiate Basketball Players’ Experiences of being Coached During a Turnaround Season

2012 ◽  
Vol 26 (1) ◽  
pp. 43-61 ◽  
Author(s):  
Andrea J. Becker
Keyword(s):  
United States ◽  
Ncaa Division I ◽  
Staff Member ◽  
The United States ◽  
Higher Order ◽  
Personality Characteristics ◽  
Division I ◽  
Basketball Players ◽  
Men's Basketball ◽  
Semistructured Interviews

The primary purpose of this study was to examine basketball players’ experiences of being coached during a turnaround season. Participants included eight collegiate men’s basketball players (ages 18–23) and one staff member representing an NCAA Division I program at a large university in the United States. All participants were involved with the basketball program during back-to-back seasons in which the team experienced a losing record (14–17) followed by a coaching change, and then a winning record (22–8) and conference championship. Semistructured interviews (lasting between 30–90 min) were conducted and transcribed verbatim. Analyses of the transcripts revealed 631 meaning units that were further grouped into lower and higher order themes. This led to the development of five major dimensions which encompassed these basketball players’ experiences of being coached during this extraordinary turnaround season including their (a) Experiences of Coach’s Personality Characteristics; (b) Experiences of Coach’s Philosophy, System, and Style of play; (c) Experiences of His Coaching Style; (d) Experiences of the Practice Environment; and (e) Experiences of How Coach Influenced Us.

Lower Body Power-Load Curves For NCAA Division I Men's and Women's Collegiate Basketball Players

2010 ◽  
Vol 42 ◽  
pp. 65
Author(s):  
Andrew C. Fry ◽  
Andrea Hudy ◽  
Philip M. Gallagher ◽  
J. Phillip Vardiman ◽  
Rebecca A. Kudrna ◽  
...  
Keyword(s):  
Ncaa Division I ◽  
Division I ◽  
Lower Body ◽  
Basketball Players ◽  
Power Load ◽  
Collegiate Basketball ◽  
Lower Body Power

scholarly journals Preliminary Scale of Reference Values for Evaluating Reactive Strength Index-Modified in Male and Female NCAA Division I Athletes

Sports ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 133 ◽  
Author(s):  
Christopher Sole ◽  
Timothy Suchomel ◽  
Michael Stone
Keyword(s):  
Reference Values ◽  
Ncaa Division I ◽  
National Collegiate Athletic Association ◽  
Collegiate Athletes ◽  
Division I ◽  
Strength Index ◽  
Male And Female ◽  
Significant Difference ◽  
Males And Females ◽  
Division I Athletes

The purpose of this analysis was to construct a preliminary scale of reference values for reactive strength index-modified (RSImod). Countermovement jump data from 151 National Collegiate Athletic Association (NCAA) Division I collegiate athletes (male n = 76; female n = 75) were analyzed. Using percentiles, scales for both male and female samples were constructed. For further analysis, athletes were separated into four performance groups based on RSImod and comparisons of jump height (JH), and time to takeoff (TTT) were performed. RSImod values ranged from 0.208 to 0.704 and 0.135 to 0.553 in males and females, respectively. Males had greater RSImod (p < 0.001, d = 1.15) and JH (p < 0.001, d = 1.41) as compared to females. No statistically significant difference was observed for TTT between males and females (p = 0.909, d = 0.02). Only JH was found to be statistically different between all performance groups. For TTT no statistical differences were observed when comparing the top two and middle two groups for males and top two, bottom two, and middle two groups for females. Similarities in TTT between sexes and across performance groups suggests JH is a primary factor contributing to differences in RSImod. The results of this analysis provide practitioners with additional insight as well as a scale of reference values for evaluating RSImod scores in collegiate athletes.

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