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Aoi Ikedo, Aya Ishibashi, Saori Matsumiya, Aya Kaizaki, Kumiko Ebi, Satoshi Fujita
We aimed to compare site-specific bone mineral densities (BMDs) between adolescent endurance runners and sprinters and examine the relationship of fat-free mass (FFM) and nutrient intake on BMD. In this cross-sectional study, 37 adolescent female endurance runners and sprinters (16.1 ± 0.8 years) were recruited. BMD and FFM were assessed by dual-energy X-ray absorptiometry. Nutrient intake and menstrual state were evaluated by questionnaires. After adjusting for covariates, spine and total bone less head (TBLH) BMDs were significantly higher in sprinters than endurance runners (TBLH, 1...
November 30, 2016: Nutrients
Erica J Roelofs, Abbie E Smith-Ryan, Eric T Trexler, Katie R Hirsch
CONTEXT:  Previous researchers have indicated the importance of body composition and muscle quality in athletic performance. However, body composition and muscle-quality measures in swimmers and divers over a training season have yet to be evaluated. OBJECTIVE:  To identify changes in body composition and muscle characteristics over a competitive season and identify relationships between these variables and performance in National Collegiate Athletic Association Division I swimmers and divers...
December 1, 2016: Journal of Athletic Training
Lucas Pereira, Ciro Winckler, Cesar C Cal Abad, Ronaldo Kobal, Katia Kitamura, Amaury Veríssimo, Fabio Y Nakamura, Irineu Loturco
This study compared the physical performance of Paralympic sprinters with visual impairments (PSVI) and their guides in jump and sprint tests. Ten PSVI and guides executed squat jumps (SJ), countermovement jumps (CMJ), horizontal quintuple right/left-leg jumps (QR/QL), decuple jumps (DEC), and 50-m-sprint tests. The guides were superior to the PSVI in SJ (35.9 ± 6.3 vs 45.6 ± 3.2 cm), CMJ (38.5 ± 6.2 vs 46.7 ± 4.0 cm), QR (9.2 ± 1.9 vs 12.7 ± 1.0 m), QL (9.4 ± 1.9 vs 13.1 ± 0.8 m), DEC (21.0 ± 3.3 vs...
October 2016: Adapted Physical Activity Quarterly: APAQ
Natsuki Sado, Shinsuke Yoshioka, Senshi Fukashiro
The purpose of this study was to investigate the effect of lumbosacral kinetics on sprinting. Twelve male sprinters performed 50 m sprints at maximal effort. Kinematic and ground reaction force data were recorded at approximately 40 m from sprint commencement. A whole-body inverse dynamics approach was applied to calculate joint forces and torques at the hip and lumbosacral joints. The contribution of the hips and lumbosacral joint torques to pelvic rotation was subsequently calculated, with joint force powers indicating the rate of mechanical energy transfer between segments across joint centres calculated for both hip joints...
November 15, 2016: Sports Biomechanics
Steffen Willwacher, Volker Herrmann, Kai Heinrich, Johannes Funken, Gerda Strutzenberger, Jan-Peter Goldmann, Björn Braunstein, Adam Brazil, Gareth Irwin, Wolfgang Potthast, Gert-Peter Brüggemann
The purpose of this study was to explore the relationship between the forces applied to the starting blocks and the start performances (SPs) of amputee sprinters (ASs) and non-amputee sprinters (NASs). SPs of 154 male and female NASs (100-m personal records [PRs], 9.58-14.00 s) and 7 male ASs (3 unilateral above knee, 3 unilateral below knee, 1 bilateral below knee; 100 m PRs, 11.70-12.70 s) with running specific prostheses (RSPs) were analysed during full-effort sprint starts using instrumented starting blocks that measured the applied forces in 3D...
2016: PloS One
Natalia Romero-Franco, Pedro Jiménez-Reyes, Adrián Castaño-Zambudio, Fernando Capelo-Ramírez, Juan José Rodríguez-Juan, Jorge González-Hernández, Francisco Javier Toscano-Bendala, Víctor Cuadrado-Peñafiel, Carlos Balsalobre-Fernández
The purpose of this study was to assess validity and reliability of sprint performance outcomes measured with an iPhone application (named: MySprint) and existing field methods (i.e. timing photocells and radar gun). To do this, 12 highly trained male sprinters performed 6 maximal 40-m sprints during a single session which were simultaneously timed using 7 pairs of timing photocells, a radar gun and a newly developed iPhone app based on high-speed video recording. Several split times as well as mechanical outputs computed from the model proposed by Samozino et al...
November 3, 2016: European Journal of Sport Science
Hiroaki Hobara, Satoru Hashizume, Yoshiyuki Kobayashi, Masaaki Mochmaru
The aim of this study was to investigate differences of the spatiotemporal parameters in a 100-m sprint among elite, sub-elite, and non-elite sprinters with a unilateral transtibial amputation. Using publicly available Internet broadcasts, we analyzed 125, 19, and 33 records from 30 elite, 12 sub-elite, and 22 non-elite sprinters, respectively. For each sprinter's run, the average velocity, step frequency, and step length were calculated using the number of steps in conjunction with the official race time. Average velocity was greatest in elite sprinters (8...
2016: PloS One
T Exell, G Irwin, M Gittoes, D Kerwin
The aim of this study was to empirically examine the interaction of athlete-specific kinematic kinetic and strength asymmetry in sprint running. Bilateral ground reaction force and kinematic data were collected during maximal velocity (mean = 9.05 m/s) sprinting for eight athletes. Bilateral ground reaction force data were also collected while the same athletes performed maximal effort squat jumps. Using novel composite asymmetry scores, interactions between kinematic and kinetic asymmetry were compared for the group of sprinters...
September 27, 2016: Scandinavian Journal of Medicine & Science in Sports
Adam Brazil, Timothy Exell, Cassie Wilson, Steffen Willwacher, Ian Bezodis, Gareth Irwin
The aim of this study was to examine lower limb joint kinetics during the block and first stance phases in athletic sprinting. Ten male sprinters (100 m PB, 10.50 ± 0.27 s) performed maximal sprint starts from blocks. External force (1000 Hz) and three-dimensional kinematics (250 Hz) were recorded in both the block (utilising instrumented starting blocks) and subsequent first stance phases. Ankle, knee and hip resultant joint moment, power and work were calculated at the rear and front leg during the block phase and during first stance using inverse dynamics...
September 6, 2016: Journal of Sports Sciences
Stacey M Rigney, Anne Simmons, Lauren Kark
Lower-limb amputees commonly utilize non-articulating energy storage and return (ESAR) prostheses for high impact activities such as sprinting. Despite these prostheses lacking an articulating ankle joint, amputee gait analysis conventionally features a two-link segment model of the prosthetic foot. This paper investigated the effects of the selected link segment model׳s marker-set and geometry on a unilateral amputee sprinter׳s calculated lower-limb kinematics, kinetics and energetics. A total of five lower-limb models of the Ottobock(®) 1E90 Sprinter were developed, including two conventional shank-foot models that each used a different version of the Plug-in-Gait (PiG) marker-set to test the effect of prosthesis ankle marker location...
October 3, 2016: Journal of Biomechanics
Simone Ciacci, Franco Merni, Sandro Bartolomei, Rocco Di Michele
The start kinematics has been reported to differ between male and female sprinters. This study aimed to determine whether kinematic differences between the sexes are attributable to an effect of sex per se, or rather to the absolute performance level of the sprinters, quantified by the 100-m time. A total of 20 sprinters (10 M, 10 F), including world-class and elite athletes, were assessed. Start phases from the "set" position to the first two steps were analysed. Linear regression analyses showed a few significant differences between sexes when taking into account the effect of performance level: M had shorter pushing phase duration, higher horizontal velocity at block clearing, and shorter contact times of the first two steps...
August 19, 2016: Journal of Sports Sciences
Takaya Yoshimoto, Yohei Takai, Hiroaki Kanehisa
This study investigated acute effects of different conditioning activities on sprint performance of collegiate sprinters using a randomized, crossover design. Male sprinters (N = 10; 20.1 ± 0.6 years; 174.6 ± 4.4 cm; 66.7 ± 3.5 kg; 100-m race personal best time, 11.46 ± 0.57 s; means ± SDs) performed two 60-m sprints and one of three treatments within the same day, with an interval of 2 days between the treatments. The baseline sprint was followed by one of three different conditioning activities: mini-hurdles, bounding jumps, or a free sprint...
2016: SpringerPlus
Gertjan Ettema, David McGhie, Jørgen Danielsen, Øyvind Sandbakk, Thomas Haugen
Accelerated running is characterised by a continuous change of kinematics from one step to the next. It has been argued that breakpoints in the step-to-step transitions may occur, and that these breakpoints are an essential characteristic of dynamics during accelerated running. We examined this notion by comparing a continuous exponential curve fit (indicating continuity, i.e., smooth transitions) with linear piecewise fitting (indicating breakpoint). We recorded the kinematics of 24 well trained sprinters during a 25 m sprint run with start from competition starting blocks...
2016: PloS One
Irineu Loturco, Ciro Winckler, Thiago F Lourenço, Amaury Veríssimo, Ronaldo Kobal, Katia Kitamura, Lucas A Pereira, Fábio Y Nakamura
BACKGROUND: Compression garments are thought to aid performance in some selected speed-power activities owing to improved sensory feedback and proprioception. The aim of this study was to test the effects of using compression garments on speed and power-related performances in elite sprinters with visual impairment, who rely more on proprioception to perform than their Olympic peers. Eight top-level Paralympic sprinters competing in 100- and 200-m races performed, in the following order: unloaded squat jump (SJ), loaded jump squat (JS) and sprint tests over 20- and 70-m distances; using or not the compression garment...
2016: SpringerPlus
Erik Schrödter, Gert-Peter Brüggemann, Steffen Willwacher
PURPOSE: This study aimed to describe the stretch shortening behavior of ankle plantarflexing muscle tendon units during the push off in a sprint start. METHODS: For this purpose, 54 male (100 m PR: 9.58-12.07 s) and 34 female (100 m PR: 11.05-14.00 s) sprinters were analyzed using an instrumented starting block and 2D high speed video imaging. Analysis was performed separately for front and rear legs, while accounting for block obliquities and performance levels...
August 24, 2016: International Journal of Sports Physiology and Performance
Ryuta Kinugasa, Yoshiyuki Usami
Usain Bolt holds the current world record in the 100-m run, with a running time of 9.58 s, and has been described as the best human sprinter in history. However, this raises questions concerning the maximum human running speed, such as "Can the world's fastest men become faster still?" The correct answer is likely "Yes." We plotted the historical world records for bipedal and quadrupedal 100-m sprint times according to competition year. These historical records were plotted using several curve-fitting procedures...
2016: Frontiers in Bioengineering and Biotechnology
Ying-Chun Wang, Na Zhang
Plyometric training (PT) is a technique used to increase strength and explosiveness. It consists of physical exercises in which muscles exert maximum force at short intervals to increase dynamic performances. In such a training, muscles undergo a rapid elongation followed by an immediate shortening (stretch-shortening contraction), utilizing the elastic energy stored during the stretching phase. There is consensus on the fact that when used, PT contributes to improvement in vertical jump performance, acceleration, leg strength, muscular power, increase of joint awareness and overall sport-specific skills...
August 2016: Experimental and Therapeutic Medicine
Patricia D Pantoja, Eduardo Saez de Villarreal, Jeanick Brisswalter, Leonardo A Peyré-Tartaruga, Jean-Benoit Morin
PURPOSE: The best sprint performances are usually reached between the ages of 20 and 30; however even in well-trained individuals, performance continues to decrease with age. While this inevitable decrease in performance has been related to reductions in muscular force, velocity and power capabilities, these measures have not been assessed in the specific context of sprinting. The aim of this study was to investigate the mechanical outputs of sprinting acceleration among Masters sprinters to better understand the mechanical underpinnings of the age-related decrease in sprint performance...
July 12, 2016: Medicine and Science in Sports and Exercise
Christopher James Manning, Sharad Singhai, Paul Marshall
No abstract text is available yet for this article.
2016: BMJ Case Reports
G G Handsfield, K R Knaus, N M Fiorentino, C H Meyer, J M Hart, S S Blemker
Sprint runners achieve much higher gait velocities and accelerations than average humans, due in part to large forces generated by their lower limb muscles. Various factors have been explored in the past to understand sprint biomechanics, but the distribution of muscle volumes in the lower limb has not been investigated in elite sprinters. In this study, we used non-Cartesian MRI to determine muscle sizes in vivo in a group of 15 NCAA Division I sprinters. Normalizing muscle sizes by body size, we compared sprinter muscles to non-sprinter muscles, calculated Z-scores to determine non-uniformly large muscles in sprinters, assessed bilateral symmetry, and assessed gender differences in sprinters' muscles...
July 4, 2016: Scandinavian Journal of Medicine & Science in Sports
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