keyword
MENU ▼
Read by QxMD icon Read
search

drop jump

keyword
https://www.readbyqxmd.com/read/28078337/a-solvable-model-of-axisymmetric-and-non-axisymmetric-droplet-bouncing
#1
Matthew Andrew, Julia M Yeomans, Dmitri O Pushkin
We introduce a solvable Lagrangian model for droplet bouncing. The model predicts that, for an axisymmetric drop, the contact time decreases to a constant value with increasing Weber number, in qualitative agreement with experiments, because the system is well approximated as a simple harmonic oscillator. We introduce asymmetries in the velocity, initial droplet shape, and contact line drag acting on the droplet and show that asymmetry can often lead to a reduced contact time and lift-off in an elongated shape...
January 12, 2017: Soft Matter
https://www.readbyqxmd.com/read/28062120/robotic-simulation-of-identical-athletic-task-kinematics-on-cadaveric-limbs-exhibits-a-lack-of-differences-in-knee-mechanics-between-contralateral-pairs
#2
Nathaniel A Bates, April L McPhearson, Rebecca J Nesbitt, Jason T Shearn, Gregory D Myer, Timothy E Hewett
Limb asymmetry is a known factor for increased ACL injury risk. These asymmetries are normally observed during in vivo testing. Prior studies have developed in vitro testing methodologies driven by in vivo kinematics to investigate knee mechanics relative to ACL injury. The objective of this study was to determine if mechanical side-to-side asymmetries persist in contralateral pairs during in vitro simulation testing. In vivo kinematics were recorded for male and female drop vertical jump and sidestep cutting tasks...
December 29, 2016: Journal of Biomechanics
https://www.readbyqxmd.com/read/28059779/effect-of-leg-compliance-in-multi-directional-jumping-of-the-flea-inspired-mechanism
#3
Gwang-Pil Jung, Hong-Cheol Choi, Kyu-Jin Cho
Inspired by the relationship between leg compliance and jumping performance in the false stick insect, this paper describes how variations in leg compliance and jumping direction affect the performance of a flea-inspired jumping mechanism. The amount of energy lost during jumping was determined by examining the ratio of kinetic energy to input energy (also called conversion efficiency). Leg compliance is modeled based on the compliant mechanics to determine energy transfer during jumping and determined the optimum degree of leg compliance for maximizing performance...
January 6, 2017: Bioinspiration & Biomimetics
https://www.readbyqxmd.com/read/28051341/effects-of-compression-garment-pressure-on-recovery-from-strenuous-exercise
#4
Jessica Hill, Glyn Howatson, Ken van Someren, David Gaze, Hayley Legg, Jack Lineham, Charles Pedlar
Compression garments are frequently used to facilitate recovery from strenuous exercise. Purpose To identify the effects of two different grades of compression garment on recovery indices following strenuous exercise. Methods Forty five recreationally active participants (n=26 males and n=19 females) completed an eccentric exercise protocol consisting of 100 drop jumps. Following the exercise protocol participants were matched for body mass and randomly but equally assigned to either a high (HI) compression pressure group, a low (LOW) compression pressure group, or a sham ultrasound group (SHAM)...
January 4, 2017: International Journal of Sports Physiology and Performance
https://www.readbyqxmd.com/read/28031754/assessing-reactive-strength-measures-in-jumping-and-hopping-using-the-optojump%C3%A2-system
#5
Robin Healy, Ian C Kenny, Andrew J Harrison
The aim of this study was to assess the concurrent validity of the Optojump™ system (Microgate, Bolzano, Italy) versus a force platform in the estimation of temporal and reactive strength measures. In two separate investigations, twenty physically active males performed double-leg and single-leg drop jumps from a box height of 0.3 m and a 10 s vertical bilateral hopping test. Contact time, flight time and total time (the sum of contact and flight time) were concurrently assessed during single and double-leg drop jumps and during hopping...
December 1, 2016: Journal of Human Kinetics
https://www.readbyqxmd.com/read/28006992/increasing-hip-and-knee-flexion-during-a-drop-jump-task-reduces-tibiofemoral-shear-and-compressive-forces-implications-for-acl-injury-prevention-training
#6
Liang-Ching Tsai, Yi-An Ko, Kyle E Hammond, John W Xerogeanes, Gordon L Warren, Christopher M Powers
Although most ACL injury prevention programmes encourage greater hip and knee flexion during landing, it remains unknown how this technique influences tibiofemoral joint forces. We examined whether a landing strategy utilising greater hip and knee flexion decreases tibiofemoral anterior shear and compression. Twelve healthy women (25.9 ± 3.5 years) performed a drop-jump task before and after a training session (10-15 min) that emphasised greater hip and knee flexion. Peak tibiofemoral anterior shear and compressive forces were calculated using an electromyography (EMG)-driven knee model that incorporated joint kinematics, EMG and participant-specific muscle volumes and patella tendon orientation measured using magnetic resonance imaging (MRI)...
December 23, 2016: Journal of Sports Sciences
https://www.readbyqxmd.com/read/27935646/postactivation-potentiation-can-counteract-declines-in-force-and-power-that-occur-after-stretching
#7
J Kümmel, A Kramer, N J Cronin, M Gruber
Stretching can decrease a muscle's maximal force, whereas short but intense muscle contractions can increase it. We hypothesized that when combined, postactivation potentiation induced by reactive jumps would counteract stretch-induced decrements in drop jump (DJ) performance. Moreover, we measured changes in muscle twitch forces and ankle joint stiffness (KAnkle ) to examine underlying mechanisms. Twenty subjects completed three DJs and 10 electrically evoked muscle twitches of the triceps surae subsequent to four different conditioning activities and control...
December 9, 2016: Scandinavian Journal of Medicine & Science in Sports
https://www.readbyqxmd.com/read/27928208/the-interaction-of-fatigue-and-potentiation-following-an-acute-bout-of-unilateral-squats
#8
Samantha K Andrews, Jesse M Horodyski, Daniel A MacLeod, Joseph Whitten, David G Behm
A prior conditioning resistance exercise can augment subsequent performance of the affected muscles due to the effects of post-activation potentiation (PAP). The non-local muscle fatigue literature has illustrated the global neural effects of unilateral fatigue. However, no studies have examined the possibility of acute non-local performance enhancements. The objective of the study was to provide a conditioning stimulus in an attempt to potentiate the subsequent jump performance of the affected limb and determine if there were performance changes in the contralateral limb...
December 2016: Journal of Sports Science & Medicine
https://www.readbyqxmd.com/read/27918704/comparison-of-3d-joint-angles-measured-with-the-kinect-2-0-skeletal-tracker-versus-a-marker-based-motion-capture-system
#9
Trent M Guess, Swithin Razu, Amirhossein Jahandar, Marjorie Skubic, Zhiyu Huo
The Microsoft Kinect is becoming a widely used tool for inexpensive, portable measurement of human motion with the potential to support clinical assessments of performance and function. In this study, the relative osteokinematic Cardan joint angles of the hip and knee were calculated using the Kinect 2.0 skeletal tracker. The pelvis segments of the default skeletal model were reoriented and three-dimensional joint angles were compared to a marker-based system during a drop vertical jump and a hip abduction motion...
December 5, 2016: Journal of Applied Biomechanics
https://www.readbyqxmd.com/read/27900188/single-leg-balance-and-core-motor-control-in-children-when-does-the-risk-for-acl-injury-occurs
#10
Allison B Hutchinson, Paul Yao, Mark R Hutchinson
INTRODUCTION: While numerous publications have demonstrated the correlation of poor single-leg balance and core motor control with an increased risk of anterior cruciate ligament (ACL) injuries in skeletally mature female athletes, few have analysed the preadolescent population regarding when indeed comparative deficits in balance and core control actually occur. The purpose of this study was to assess whether the neuromotor factors that place mature females at increased risk of ACL injury actually are present in preadolescents and if so when...
2016: BMJ Open Sport & Exercise Medicine
https://www.readbyqxmd.com/read/27899894/moderate-load-eccentric-exercise-a-distinct-novel-training-modality
#11
REVIEW
Hans Hoppeler
Over the last 20 years a number of studies have been published using progressive eccentric exercise protocols on motorized ergometers or similar devices that allow for controlled application of eccentric loads. Exercise protocols ramp eccentric loads over an initial 3 weeks period in order to prevent muscle damage and delayed onset muscle soreness. Final training loads reach 400-500 W in rehabilitative settings and over 1200 W in elite athletes. Training is typically carried out three times per week for durations of 20-30 min...
2016: Frontiers in Physiology
https://www.readbyqxmd.com/read/27893481/the-effect-of-exercise-induced-muscle-damage-after-a-bout-of-accentuated-eccentric-load-drop-jumps-and-the-repeated-bout-effect
#12
Lee A Bridgeman, Nicholas D Gill, Deborah K Dulson, Michael R McGuigan
Although previous studies have investigated exercise induced muscle damage (EIMD) after a bout of unloaded drop jumps (DJ) none have investigated the effects of accentuated eccentric load (AEL) DJs on EIMD. The purpose of this study was to investigate the effects of 30 and 50 AEL DJs on strength, jump performance, muscle soreness and blood markers. Eight resistance trained athletes participated in this study. In week 1 baseline countermovement jump (CMJ), squat jump (SJ), concentric and eccentric peak force (PF), creatine kinase (CK) and muscle soreness (SOR) were assessed...
November 16, 2016: Journal of Strength and Conditioning Research
https://www.readbyqxmd.com/read/27893474/hypertrophy-and-explosive-reactive-functioning-in-sedentary-men-following-10-weeks-of-whole-body-vibration
#13
Jens Ebing, Ulf Gast, Christoph Hauptmann, Dieter Felsenberg, Daniel L Belavý
The objective of this study was to determine the impact of vertical (Power-plate; POW) and side-alternating (Galileo; GAL) whole-body vibration exercise on muscle mass and lower-limb neuromuscular function. Forty-three sedentary male subjects (18-30yr) randomized into three groups underwent two upper-body exercise sessions per week for 10 weeks. Two groups of subjects underwent additional squat exercises on the GAL (N=15) or POW (N=14) devices. The third group was control. On magnetic resonance imaging, volume of the thigh muscles was measured...
November 16, 2016: Journal of Strength and Conditioning Research
https://www.readbyqxmd.com/read/27877843/thermally-conductive-polyamide-6-carbon-filler-composites-based-on-a-hybrid-filler-system
#14
Sung Min Ha, O Hwan Kwon, Yu Gyeong Oh, Yong Seok Kim, Sung-Goo Lee, Jong Chan Won, Kwang Soo Cho, Byoung Gak Kim, Youngjae Yoo
We explored the use of a hybrid filler consisting of graphite nanoplatelets (GNPs) and single walled carbon nanotubes (SWCNTs) in a polyamide 6 (PA 6) matrix. The composites containing PA 6, powdered GNP, and SWCNT were melt-processed and the effect of filler content in the single filler and hybrid filler systems on the thermal conductivity of the composites was examined. The thermal diffusivities of the composites were measured by the standard laser flash method. Composites containing the hybrid filler system showed enhanced thermal conductivity with values as high as 8...
December 2015: Science and Technology of Advanced Materials
https://www.readbyqxmd.com/read/27876280/validity-and-intra-rater-reliability-of-myjump-app-on-iphone-6s-in-jump-performance
#15
Robert Stanton, Sally-Anne Wintour, Crystal O Kean
OBJECTIVES: Smartphone applications are increasingly used by researchers, coaches, athletes and clinicians. The aim of this study was to examine the concurrent validity and intra-rater reliability of the smartphone-based application, MyJump, against laboratory-based force plate measurements. DESIGN: Cross sectional study. METHODS: Participants completed counter-movement jumps (CMJ) (n=29) and 30cm drop jumps (DJ) (n=27) on a force plate which were simultaneously recorded using MyJump...
November 11, 2016: Journal of Science and Medicine in Sport
https://www.readbyqxmd.com/read/27874298/volitional-spine-stabilization-during-a-drop-vertical-jump-from-different-landing-heights-implications-for-anterior-cruciate-ligament-injury
#16
Ram Haddas, Troy Hooper, C Roger James, Phillip S Sizer
CONTEXT:  Volitional spine stabilization (VSS) during dynamic activities may alter trunk motion, but the role of the core musculature in positioning the trunk during landing tasks is unclear. OBJECTIVE:  To determine whether volitional core-muscle activation incorporated during a drop vertical jump alters lower extremity kinematics and kinetics, as well as trunk and lower extremity muscle activity at different landing heights. DESIGN:  Controlled laboratory study...
November 22, 2016: Journal of Athletic Training
https://www.readbyqxmd.com/read/27826398/four-weeks-of-supplementation-with-isolated-soy-protein-attenuates-exercise-induced-muscle-damage-and-enhances-muscle-recovery-in-well-trained-athletes-a-randomized-trial
#17
Shweta Shenoy, Mrinal Dhawan, Jaspal Singh Sandhu
BACKGROUND: The effects of consumption of isolated soy protein (ISP) for a chronic period (4 weeks) on exercise induced muscle damage (EIMD) in athletic population have never been explored. OBJECTIVES: To examine the effects of ISP on muscle damage indices elicited via a bout of damaging exercise. PATIENTS AND METHODS: Forty males (20 boxers, 20 cyclists) aged 18 - 28 years were randomly assigned to two groups (ISP and Placebo) (n = 20). All participants who engaged themselves in specific, regular training of 30 hours a week during the competitive season were included in the study...
September 2016: Asian Journal of Sports Medicine
https://www.readbyqxmd.com/read/27820725/training-strategies-to-improve-muscle-power-is-olympic-style-weightlifting-relevant
#18
Christian Helland, Eirik Hole, Erik Iversen, Monica Charlotte Olsson, Olivier Seynnes, Paul Andre Solberg, Gøran Paulsen
INTRODUCTION: This efficacy study investigated the effects of (1) Olympic-style weightlifting (OWL), (2) motorized strength and power training (MSPT), and (3) free weight strength and power training (FSPT) on muscle power. METHODS: Thirty-nine young athletes (20±3 yr.; ice hockey, volleyball and badminton) were randomized into the three training groups. All groups participated in 2-3 sessions/week for 8 weeks. The MSPT and FSPT groups trained using squats (two legs and single leg) with high force and high power, while the OWL group trained using clean and snatch exercises...
November 3, 2016: Medicine and Science in Sports and Exercise
https://www.readbyqxmd.com/read/27813394/adaptations-in-movement-performance-after-plyometric-training-on-mini-trampoline-in-children
#19
Fotini Arabatzi
BACKGROUND: Deficits in postural control and skill performance are important intrinsic fall risk factors. Thus, the purpose of this study was to investigate the impact of trampoline plyometrics on postural control, and jumping height in pre-pubertal children. METHODS: Twenty-two school children were assigned to either a Trampoline group (TPLG, n = 12, 7 girls & 5 boys, age = 9.30 ± 0.55 years) or a Control group (CG, n = 12, 8 girls & 4 boys, age = 9.30 ± 0.55 years)...
November 4, 2016: Journal of Sports Medicine and Physical Fitness
https://www.readbyqxmd.com/read/27803627/muscle-contraction-velocity-a-suitable-approach-to-analyze-the-functional-adaptations-in-elite-soccer-players
#20
Irineu Loturco, Lucas A Pereira, Ronaldo Kobal, Katia Kitamura, Rodrigo Ramírez-Campillo, Vinicius Zanetti, Cesar C Cal Abad, Fabio Y Nakamura
Tensiomyography (TMG) has been used as a simple and non-invasive tool to assess the mechanical properties of skeletal muscles. The TMG-derived velocity of contraction (Vc), which can be calculated from the ratio between maximal radial displacement and the sum of contraction time and delay time, has been proposed for evaluating athletes. However, its sensitivity to training effects and possible relation with changes in soccer players' neuromuscular performance have not yet been addressed. To test this possibility, twenty-two male Brazilian elite soccer players were assessed using TMG-derived Vc, unloaded squat jump, countermovement jump and drop jump at 45 cm, loaded jump squat and linear (20 m) and change of direction (COD) sprint tests, prior to and after an 8-week period, between two consecutive official tournaments, during which the concurrency between endurance and strength-power training commonly impairs neuromuscular capacities...
September 2016: Journal of Sports Science & Medicine
keyword
keyword
91135
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"