The effect of overhead target on the lower limb biomechanics during a vertical drop jump test in elite female athletes

2015 ◽  
Vol 27 (2) ◽  
pp. 161-166 ◽  
Author(s):  
K-M. Mok ◽  
R. Bahr ◽  
T. Krosshaug
2005 ◽  
Vol 33 (2) ◽  
pp. 197-207 ◽  
Author(s):  
Frank R. Noyes ◽  
Sue D. Barber-Westin ◽  
Cassie Fleckenstein ◽  
Cathy Walsh ◽  
John West

Background A valgus lower limb alignment has been noted during noncontact anterior cruciate ligament injuries. A video dropjump test can indicate an athlete's ability to control lower limb axial alignment in the coronal plane. Hypotheses Female athletes have decreased knee separation distances on landing and acceleration; male athletes have a neutrally aligned lower limb position. A neuromuscular training program will significantly increase knee separation distance in female athletes. Study Design Cohort study; Level of evidence, 2. Methods The authors tested 325 female and 130 male athletes aged 11 to 19 years. The distance between the hips, knees, and ankles was measured during a drop-jump test. The separation distance between the knees and ankles was normalized by the hip separation distance. A neuromuscular training program (Sportsmetrics) was completed by 62 female athletes, and their jump-landing characteristics were reexamined. Results A marked decrease in knee separation distance was found on takeoff in 80% of female athletes and in 72% of male athletes. There was no difference between male and female athletes in the normalized knee and ankle separation distance during the landing and takeoff phases. The knee separation distance on landing was 23 ± 9 cm in the female athletes and 22 ± 8 cm in the male athletes. The normalized knee separation distance was 51% ± 19% in the female athletes and 51% ± 15% in the male athletes. After training, statistically significant increases were found in the female athletes in the knee separation distance on landing (29 ± 8 cm, P<. 0001) and in the normalized knee separation distance (68% ± 18%, P<. 0001). The trained female athletes had significantly greater knee separation distance and normalized knee separation distance than did the males (P<. 0001). Conclusions The majority of untrained female and male athletes demonstrated a valgus alignment appearance on the video test. After neuromuscular training, female athletes had improved knee separation distances and a more neutral lower limb alignment on landing and takeoff.


Author(s):  
L. Derek Gerber ◽  
Evan V. Papa ◽  
Eydie A. Kendall

Background: Dynamic knee valgum is a major risk factor in ligamentous injuries of the knee. Different sports have higher rates of knee ligament injury than others and females experience knee non-contact ligament injuries at higher rates than their male counterparts. Objectives: The purpose of this study was to investigate the lower extremity biomechanics of genu valgum in female collegiate athletes of various sports while performing a drop jump test. This information may provide those designing individualized prevention programs assistance in reducing risk of knee ligamentous injury during jumping tasks. Methods: Current members of Idaho State University’s women’s basketball, soccer, and softball teams were evaluated for this study. Thirty-seven athletes participated. Motion capture reflective markers were placed bilaterally on the lower extremities to allow for analysis of knee biomechanics during a double-leg drop jump test. The angles of knee valgum in the frontal plane were calculated and analyzed between sport groups. Results: Female athletes of different sports displayed statistically significant differences in knee angles for both right, and left knees. Post hoc analysis with a Bonferroni adjustment revealed that basketball players utilized a more valgus right knee angle compared to both soccer and softball players and a more varus left knee angle compared with softball players. Conclusions: Our study suggests that collegiate-level female basketball players have an increased risk of right leg non-contact knee ligament injury during jump landing maneuvers when compared to collegiate level softball and soccer players due to increased knee valgus movements during the drop jump test. Collegiate-level female basketball players may benefit from biomechanical exercise interventions designed to decrease right knee valgus moments in jumping and landing to decrease their risk of injury.


2005 ◽  
Vol 33 (12) ◽  
pp. 1853-1860 ◽  
Author(s):  
Sue D. Barber-Westin ◽  
Marc Galloway ◽  
Frank R. Noyes ◽  
George Corbett ◽  
Catherine Walsh

Background Although neuromuscular indices have been extensively studied in adolescents and adults, limited data exist for prepubescent children. Hypothesis No differences exist between prepubescent boys and girls in lower limb strength, symmetry on single-legged hop testing, and limb alignment during drop-jump testing. Study Design Cross-sectional study (prevalence); Level of evidence, 1. Methods The authors tested 27 female and 25 male athletes who were aged 9 to 10 years and matched for both body mass index and years of organized sports participation. In a drop-jump screening test, the distance between the right and left hips, knees, and ankles was measured as an indicator of lower limb axial alignment in the coronal plane. The distance between the knees and ankles was normalized by the hip separation distance. Quadriceps and hamstrings strengths were measured isokinetically at 180 deg/s. Lower limb symmetry was determined from 2 single-legged hop function tests. Results Boys demonstrated greater mean absolute and normalized knee and ankle separation distances on the drop-jump test. Even so, 76% of boys had a normalized knee separation distance of 60% or less of the hip separation distance, as did 93% of girls, indicating a distinctly valgus alignment. There were no differences between the sexes in quadriceps and hamstrings peak torques, hamstrings/quadriceps ratio, time to peak torque, total work, or lower limb symmetry values. Conclusions A high percentage of the prepubescent athletes studied had a distinctly valgus lower limb alignment during the drop-jump test and a lack of lower limb symmetry during the hop tests. These same indices have been hypothesized to increase the risk for knee ligament injuries in older athletes. Neuromuscular training may be needed to address these issues in children.


2019 ◽  
Vol 14 (9) ◽  
pp. 1200-1204
Author(s):  
Thomas M. Comyns ◽  
Eamonn P. Flanagan ◽  
Sean Fleming ◽  
Evan Fitzgerald ◽  
Damian J. Harper

Purpose: To examine the interday reliability and usefulness of a reactive strength index (RSI) derived from a maximal 5-rebound jump test (5max RJT) and a maximal 10-rebound jump test (10/5 RJT). Methods: Twenty male field-sport athletes (24.5 [3.0] y, 1.78 [0.1] m, 84.9 [5.2] kg) and 15 female participants (21.1 [0.9] y, 1.65 [0.73] m, 62.0 [5.1] kg) performed 2 maximal repetitions of the 5max RJT and the 10/5 RJT on 2 testing days after a specific warm-up. A 1-wk period separated testing days, and these sessions were preceded by a familiarization session. RSI was calculated by dividing jump height (in meters) by contact time (in seconds). The 5max RJT and the 10/5 RJT trial with the highest RSI on each testing day were used for reliability and usefulness analysis. Results: Both tests were deemed reliable for determining RSI for male, female, and pooled male and female cohorts, as the intraclass correlation coefficients were ≥.80 and the coefficient of variation was ≤10%. Only the 5max RJT was rated as “good” at detecting the smallest worthwhile change in performance for female athletes (smallest worthwhile change: 0.10 > typical error: 0.07). The 5max RJT for men and the 10/5 RJT for men and women were rated “good” in detecting a moderate change in performance only. Conclusions: Both tests are reliable for the determination of RSI, but the usefulness of the tests in detecting the smallest worthwhile change is questionable.


Sports ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 104
Author(s):  
Konstantina Karagianni ◽  
Olyvia Donti ◽  
Christos Katsikas ◽  
Gregory C. Bogdanis

This study examined the effects of a short-duration supplementary strength–power training program on neuromuscular performance and sport-specific skills in adolescent athletes. Twenty-three female “Gymnastics for All” athletes, aged 13 ± 2 years, were divided into a training group (TG, n = 12) and a control group (CG, n = 11). Both groups underwent a test battery before and after 10 weeks of intervention. TG completed, in addition to gymnastics training, a supplementary 7–9 min program that included two rounds of strength and power exercises for arms, torso, and legs, executed in a circuit fashion with 1 min rest between rounds, three times per week. Initially, six exercises were performed (15 s work–15 s rest), while the number of exercises was decreased to four and the duration of each exercise was increased to 30 s (30 s rest) after the fifth week. TG improved countermovement jump performance with one leg (11.5% ± 10.4%, p = 0.002) and two legs (8.2% ± 8.8%, p = 0.004), drop jump performance (14.4% ± 12.6%, p = 0.038), single-leg jumping agility (13.6% ± 5.2%, p = 0.001), and sport-specific performance (8.8% ± 7.4%, p = 0.004), but not 10 m sprint performance (2.4% ± 6.6%, p = 0.709). No change was observed in the CG (p = 0.41 to 0.97). The results of this study indicated that this supplementary strength–power program performed for 7–9 min improves neuromuscular and sport-specific performance after 10 weeks of training.


2019 ◽  
Vol 31 (4) ◽  
pp. 465-472 ◽  
Author(s):  
Mehrez Hammami ◽  
Rodrigo Ramirez-Campillo ◽  
Nawel Gaamouri ◽  
Gaith Aloui ◽  
Roy J. Shephard ◽  
...  

Purpose: To analyze the effects of a 9-week plyometric training program on the sprint times (5, 10, 20, and 30 m), change-of-direction speed (modified T test and modified Illinois test), jumping (squat jump, countermovement jump, countermovement jump with arms, and horizontal 5-jump test), upper-body strength (right and left handgrip, back extensor strength, and medicine ball throw), and balance (Y and stork balance tests) of female handball players. Methods: Athletes were randomly divided into experimental (n = 21; age = 13.5 [0.3] y) and control (n = 20; age = 13.3 [0.3] y) groups. Training exercises and matches were performed together, but the experimental group replaced a part of their normal regimen by biweekly upper- and lower-limb plyometric training. Results: Both groups improved performance, but to a greater extent in the experimental group compared with controls for 20- and 30-m sprint times (Δ% = 9.6, P < .05, d = 0.557 and Δ% = 20.9, P < .001, d = 1.07, respectively), change of direction (T test: P < .01, Δ% = 14.5, d = 0.993 and Illinois test: P < .01, Δ% = 7.9, d = 0.769), vertical and horizontal jumping (P < .05), all measures of upper-limb strength (P < .001), and left-leg stork balance (P < .001, Δ% = 49.9, d = 1.07). Conclusions: A plyometric training program allows female junior handball players to improve important components of their physical performance.


2017 ◽  
Vol 73 (2) ◽  
pp. 140-145 ◽  
Author(s):  
Anup Krishnan ◽  
Deep Sharma ◽  
Madhu Bhatt ◽  
Apoorv Dixit ◽  
P. Pradeep

2018 ◽  
Vol 61 (1) ◽  
pp. 131-140
Author(s):  
Daniel Castillo ◽  
Javier Yanci ◽  
Jesús Cámara

Abstract The evaluation of match officials’ neuromuscular performance is now an important consideration and the vertical jump test is considered suitable for assessing lower limb power, partly because it is directly related to refereeing. The aim of this study, therefore, was to determine the effect of soccer matches on match officials’ vertical jump performance by assessing various biomechanical variables. Eighteen field referees (FRs) and 36 assistant referees (ARs) who officiated in 18 official matches participated in this study. Before the match, at half time and immediately after the match, officials performed two countermovement jumps. Flight phase time (FT), maximum force production (MFpropulsion), time to production of maximum force (TMFpropulsion), production of maximum power (MP), maximum landing force (MFlanding) and time to stabilization (TTS) were calculated for all jumps. There was a tendency for match officials’ jumping performance to improve after matches than beforehand (FR: effect size (ES) = 0.19 ± 0.36, possibly trivial; AR: ES = 0.07 ± 0.17, likely trivial). There were also likely small and very likely moderate differences between FRs’ MP in pre-match and half-time jumps (ES = 0.46 ± 0.47) and in their pre- and post-match jumps (ES = 0.71 ± 0.48). These results indicate that refereeing soccer matches does not reduce vertical jump performance; the subsequent neuromuscular fatigue is not sufficient to affect landing technique.


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