Ankle Orthosis-induced Decrease in Repetitive Rebound Jump Height: Relationship With Restriction in Sagittal Ankle Range of Motion

Abstract Background: Ankle orthotics decreases the maximal vertical jump height. It is essential to maximize jump height and minimize ground contact time during athletic performance. However, the effect of ankle orthotics on athletic performance has not been reported. We aimed to investigate the effect of ankle orthotics on squat jump (SJ), countermovement jump (CMJ), and repetitive rebound jump (RJ) performance and the relationship between jump performance and restriction in sagittal ankle range of motion. Methods: Twenty healthy volunteers performed SJ, CMJ, repetitive RJ under no-orthosis and two orthotic conditions (orthosis 1 and orthosis 2). During SJ and CMJ, we measured the vertical ground reaction force and calculated the following parameters: jump height, peak vertical ground reaction force, rate of force development, net vertical impulse, and peak power. During repetitive RJ, the jump height, contact time, and RJ index were measured. A two-dimensional motion analysis was used to quantify the ankle range of motion in the sagittal plane during SJ, CMJ, and repetitive RJ. Results: Multivariate analysis of variance and the post hoc test showed a significant decrease in the vertical jump height (p = 0.003), peak power (p = 0.007), and maximum plantarflexion and dorsiflexion angles (p <0.001) during SJ using orthosis 2 compared to those using the no-orthosis condition. Additionally, orthosis 2 significantly decreased the jump height at the end of repetitive RJ (p = 0.046), during which a significant negative correlation was found between jump height and maximum dorsiflexion angle (r = 0.485, p = 0.030). Conclusions: An ankle orthosis-induced restriction of dorsiflexion is associated with a reduction in jump height during static jump and repetitive RJ performance.

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Optimum Drop Jump Height in Division III Athletes: Under 75% of Vertical Jump Height

International Journal of Sports Medicine ◽

10.1055/s-0043-114011 ◽

2017 ◽

Vol 38 (11) ◽

pp. 842-846 ◽

Cited By ~ 3

Author(s):

Hsien-Te Peng ◽

Cong Khuat ◽

Thomas Kernozek ◽

Brian Wallace ◽

Shin-Liang Lo ◽

...

Keyword(s):

Impact Force ◽

Vertical Jump ◽

Reaction Force ◽

Jump Height ◽

Drop Jump ◽

Division Iii ◽

Vertical Ground Reaction Force ◽

Joint Power ◽

Vertical Jump Height ◽

Vertical Ground

AbstractOur purpose was to evaluate the vertical ground reaction force, impulse, moments and powers of hip, knee and ankle joints, contact time, and jump height when performing a drop jump from different drop heights based on the percentage of a performer’s maximum vertical jump height (MVJH). Fifteen male Division III athletes participated voluntarily. Eleven synchronized cameras and two force platforms were used to collect data. One-way repeated-measures analysis of variance tests were used to examine the differences between drop heights. The maximum hip, knee and ankle power absorption during 125%MVJH and 150%MVJH were greater than those during 75%MVJH. The impulse during landing at 100%MVJH, 125%MVJH and 150%MVJH were greater than 75%MVJH. The vertical ground reaction force during 150%MVJH was greater than 50%MVJH, 75%MVJH and 100%MVJH. Drop height below 75%MVJH had the most merits for increasing joint power output while having a lower impact force, impulse and joint power absorption. Drop height of 150%MVJH may not be desirable as a high-intensity stimulus due to the much greater impact force, increasing the risk of injury, without increasing jump height performance.

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Biomechanical Comparison in Different Jumping Tasks Between Untrained Boys and Men

Pediatric Exercise Science ◽

10.1123/pes.25.1.101 ◽

2013 ◽

Vol 25 (1) ◽

pp. 101-113 ◽

Cited By ~ 17

Author(s):

Savvas N. Lazaridis ◽

Eleni I. Bassa ◽

Dimitrios Patikas ◽

Konstantinos Hatzikotoulas ◽

Filippos K. Lazaridis ◽

...

Keyword(s):

Vertical Jump ◽

Reaction Force ◽

Knee Kinematics ◽

Emg Activity ◽

Drop Jump ◽

Adult Males ◽

Vertical Ground Reaction Force ◽

Vertical Ground ◽

Biomechanical Comparison ◽

Braking Phase

This study examines the biomechanical differences during different vertical jump tasks in 12 prepubescent and 12 adult males. The sagittal knee kinematics, vertical ground reaction force (vGRF) and electromyographic (EMG) activity of 5 lower extremity muscles were recorded. Compared with boys, men presented higher peak vGRF during the propulsive phase in all examined jumps, but lower values during the braking phase, even when related to body mass. Normalized EMG agonist activity in all phases was higher in men (p < .05), while antagonist coactivation was enhanced in boys (p < .05). The knee joint was on average 9 degrees more flexed at touchdown in men during drop jump tasks, but boys exhibited 12 degrees and 17 degrees higher knee flexion at the deepest point when performing drop jump from 20 and 40 cm, respectively. In conclusion, the performance deficit observed in boys in all jump types is a reflection of their immature technique, which could be partly attributed to the less efficient stiffness regulation and activation of their neuromuscular system.

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Pelvic Kinematic Method for Determining Vertical Jump Height

Journal of Applied Biomechanics ◽

10.1123/jab.26.4.508 ◽

2010 ◽

Vol 26 (4) ◽

pp. 508-511 ◽

Cited By ~ 17

Author(s):

Loren Z.F. Chiu ◽

George J. Salem

Keyword(s):

Vertical Jump ◽

Center Of Mass ◽

Reaction Force ◽

Jump Height ◽

Impulse Method ◽

Vertical Jump Height ◽

Reconstruction Methods ◽

Kinematic Method ◽

Mass Displacement ◽

Vertical Jumps

Sacral marker and pelvis reconstruction methods have been proposed to approximate total body center of mass during relatively low intensity gait and hopping tasks, but not during a maximum effort vertical jumping task. In this study, center of mass displacement was calculated using the pelvic kinematic method and compared with center of mass displacement using the ground-reaction force-impulse method, in experienced athletes (n= 13) performing restricted countermovement vertical jumps. Maximal vertical jumps were performed in a biomechanics laboratory, with data collected using an 8-camera motion analysis system and two force platforms. The pelvis center of mass was reconstructed from retro-reflective markers placed on the pelvis. Jump height was determined from the peak height of the pelvis center of mass minus the standing height. Strong linear relationships were observed between the pelvic kinematic and impulse methods (R2= .86;p< .01). The pelvic kinematic method underestimated jump height versus the impulse method, however, the difference was small (CV = 4.34%). This investigation demonstrates concurrent validity for the pelvic kinematic method to determine vertical jump height.

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The Effect of Longer versus Shorter Duration of Supervised Physiotherapy after ACL Reconstruction on the Vertical Jump Landing Limb Symmetry

BioMed Research International ◽

10.1155/2018/7519467 ◽

2018 ◽

Vol 2018 ◽

pp. 1-7 ◽

Cited By ~ 5

Author(s):

Aleksandra Królikowska ◽

Andrzej Czamara ◽

Łukasz Szuba ◽

Paweł Reichert

Keyword(s):

Vertical Jump ◽

Reaction Force ◽

Vertical Ground Reaction Force ◽

Group Iii ◽

Jump Landing ◽

Group I ◽

Intergroup Comparison ◽

Vertical Ground ◽

Group Ii ◽

The One

The study investigated the vertical jump landing limb symmetry after ACLR between a group of patients receiving a longer supervised physiotherapeutic procedure and following a shorter supervised physiotherapy. Group I (n=20) and Group II (n=15) were males averagely 30 weeks after ACLR. The time since ACLR in both groups (Group I, 27.95 ± 8.26 weeks; Group II, 32.47 ± 7.74 weeks) was insignificant, although the duration of supervised physiotherapy between the two groups (Group I, 27.9 ± 8.26 weeks; Group II, 11.28 ± 8.20 weeks) significantly differenced. Group III (n=20) were controls. Two-legged and one-legged vertical jumps landing vertical ground reaction force (VGRF) were bilaterally measured in all groups using force plates. The intragroup comparison of two-legged jump landing VGRF revealed p=0.01 between the involved and uninvolved limbs in Group II. The intergroup comparison revealed p≤0.001 in the two-legged vertical jump between Groups II and III, and I and II. The one-legged limb symmetry was comparable in studied groups. In the group following shorter supervised physiotherapy, the two-legged landing limb symmetry was on a worse level than in the group of patients receiving fully supervised procedure and healthy individuals. A fully supervised postoperative physiotherapy is more effective for improving two-legged vertical jump landing limb symmetry.

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Lower-Extremity-Joint Cryotherapy Does Not Affect Vertical Ground-Reaction Forces during Landing

Journal of Sport Rehabilitation ◽

10.1123/jsr.10.2.132 ◽

2001 ◽

Vol 10 (2) ◽

pp. 132-142 ◽

Cited By ~ 12

Author(s):

Andrew G Jameson ◽

Stephen J Kinzey ◽

Jeffrey S Hallam

Keyword(s):

Repeated Measures ◽

Vertical Jump ◽

Reaction Force ◽

Vertical Ground Reaction Force ◽

Physically Active ◽

Before And After ◽

Reaction Forces ◽

Vertical Ground ◽

Chronic Injuries ◽

Vertical Ground Reaction Forces

Context:Cryotherapy is commonly used in the care of acute and chronic injuries. It decreases pain, reduces swelling, and causes vasoconstriction of blood vessels. Its detrimental effects on motor activity might predispose physically active individuals to further injury.Objective:To examine the effects of cryotherapy on vertical-ground-reaction-force (VGRF) during a 2-legged landing from a 2-legged targeted vertical jump.Design:2 × 4 MANOVA with repeated measures.Setting:Biomechanics laboratory.Participants:10 men, means: 22.40 ± 1.26 years, 76.01 ± 26.95 kg, 182.88 ± 6.88 cm.Intervention:VGRF during landing from a targeted vertical jump (90% of maximum) was measured before and after four 20-minute cryotherapy treatments.Results:There were no significant differences in VGRF as a result of cryotherapy.Conclusion:Under the constraints of this study there is no evidence that returning to activity immediately after cryotherapy predisposes an athlete to injury because of a change in VGRF.

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NFL Draft Prep Players Improve 40-Yard Run Times and Foot-Ground Kinetics

Research Directs in Strength and Performance ◽

10.53520/rdsp2021.1056 ◽

2021 ◽

Vol 1 (1) ◽

Author(s):

Monique Mokha ◽

Tobin Silver ◽

Pete Bommarito

Keyword(s):

Contact Time ◽

National Football League ◽

Reaction Force ◽

American Football ◽

Football Players ◽

Ground Contact ◽

Vertical Ground Reaction Force ◽

Linear Speed ◽

Vertical Ground ◽

Ground Contact Time

Introduction: Linear speed is a discriminant factor between drafted and undrafted American football players into the National Football League. Linear speed is influenced by foot-ground contact time and the magnitude of vertical ground reaction force. The aim of this study was to determine if foot-ground kinetics during speed running could be modified through participating in a 6-week NFL draft preparation camp. Methods: To evaluate foot-ground kinetics, 16 American football players ran on an instrumented treadmill for 5 seconds at 6.5 m/s. Linear speed was measured during a 40-yard (36.6 m) outdoor run. Pre- and post-camp linear speed times, stance-averaged vertical ground reaction forces (vGRF, kg/N), foot-ground contact time (msec), and vertical impulse (kg/N * s) were examined using paired t-tests, p<.05. Results: Linear speed times significantly improved [(pre, 4.8±0.2 vs. post, 4.6±0.2 sec), t(15)=13.8, p<.001)], and foot-ground contact time significantly decreased for the right limb [(pre, 177+3.2 vs. post, 168+2.2 ms), t(15)=2.21, p=.043]. Mean vertical impulse and stance-averaged GRF for both limbs remained unchanged, p>.05. Conclusions: Linear speed and selected foot-ground kinetics are modifiable in NFL draft prep players. Training appears to lower 40-yard run times and foot-ground contact time.

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Is There An Optimal Vertical Ground Reaction Force Profile For Maximizing Jump Height In A Countermovement Jump?

Medicine & Science in Sports & Exercise ◽

10.1249/01.mss.0000676400.58371.20 ◽

2020 ◽

Vol 52 (7S) ◽

pp. 261-262

Author(s):

Josef A. Cohen ◽

Malachy P. McHugh ◽

Marc Hickok ◽

Declan AJ Connolly

Keyword(s):

Ground Reaction Force ◽

Reaction Force ◽

Jump Height ◽

Countermovement Jump ◽

Vertical Ground Reaction Force ◽

Force Profile ◽

Vertical Ground

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The Effects of Cryotherapy on Ground-Reaction Forces Produced during a Functional Task

Journal of Sport Rehabilitation ◽

10.1123/jsr.9.1.3 ◽

2000 ◽

Vol 9 (1) ◽

pp. 3-14 ◽

Cited By ~ 15

Author(s):

Stephen J. Kinzey ◽

Mitchell L. Cordova ◽

Kevin J. Gallen ◽

Jason C. Smith ◽

Justin B. Moore

Keyword(s):

Outcome Measures ◽

Ground Reaction Force ◽

Repeated Measures ◽

Vertical Jump ◽

Weight Bearing ◽

Reaction Force ◽

Ground Reaction Forces ◽

Vertical Ground Reaction Force ◽

Reaction Forces ◽

Vertical Ground

Objective:To determine whether a standard 20-min ice-bath (10°C) immersion of the leg alters vertical ground-reaction-force components during a 1 -legged vertical jump.Design:A 1 × 5 factorial repeated-measures model was used.Setting:The Applied Biomechanics Laboratory at The University of Mississippi.Participants:Fifteen healthy and physically active subjects (age = 22.3 ± 2.1 years, height = 177.3 ± 12.2 cm, mass = 76.3 ± 19.1 kg) participated.Intervention:Subjects performed 25 one-legged vertical jumps with their preferred extremity before (5 jumps) and after (20 jumps) a 20-min cold whirlpool to the leg. The 25 jumps were reduced into 5 sets of average trials.Main Outcome Measures:Normalized peak and average vertical ground-reaction forces, as well as vertical impulse obtained using an instrumented force platform.Results:Immediately after cryotherapy (sets 2 and 3), vertical impulse decreased (P= .01); peak vertical ground-reaction force increased (set 2) but then decreased toward baseline measures (P= .02). Average vertical ground-reaction force remained unchanged (P>.05).Conclusions:The authors advocate waiting approximately 15 min before engaging in activities that require the production of weight-bearing explosive strength or power.

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