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Todd L. Allinger and Robert W. Motl

This study used a vertical jump model to simulate the push-off phase for a skater using klap speed skates and evaluated die effects of pivot location and shoe base flexion on energy production. Boards of different lengths and one board with a hinge under the metatarsal heads were attached to the running shoes of volunteers. Six skaters performed 3 maximal effort vertical jumps across 5 different base conditions: running shoe, board that hinged under metatarsal heads, and rigid boards that pivoted with the ground al -25 mm (typical pivot location for klapskales), 0 mm, and +25 mm from the toes. There were no significant differences in total energy at take-off among the 3 rigid base conditions, but there were differences in potential and kinetic energy production. The total and kinetic energy produced at take-off was 9% greater in the hinged base condition than the corresponding rigid base condition. If differences in energy measures from the vertical jump reflect those for skating, a hinged boot base could increase skating speeds by about 3% over the current klap-skales, which have a rigid boot base.

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Yoann Blache, Maarten Bobbert, Sebastien Argaud, Benoit Pairot de Fontenay and Karine M. Monteil

In experiments investigating vertical squat jumping, the HAT segment is typically defined as a line drawn from the hip to some point proximally on the upper body (eg, the neck, the acromion), and the hip joint as the angle between this line and the upper legs (θUL-HAT). In reality, the hip joint is the angle between the pelvis and the upper legs (θUL-pelvis). This study aimed to estimate to what extent hip joint definition affects hip joint work in maximal squat jumping. Moreover, the initial pelvic tilt was manipulated to maximize the difference in hip joint work as a function of hip joint definition. Twenty-two male athletes performed maximum effort squat jumps in three different initial pelvic tilt conditions: backward (pelvisB), neutral (pelvisN), and forward (pelvisF). Hip joint work was calculated by integrating the hip net joint torque with respect to θUL-HAT (WUL-HAT) or with respect to θUL-pelvis (WUL-pelvis). θUL-HAT was greater than θUL-pelvis in all conditions. WUL-HAT overestimated WUL-pelvis by 33%, 39%, and 49% in conditions pelvisF, pelvisN, and pelvisB, respectively. It was concluded that θUL-pelvis should be measured when the mechanical output of hip extensor muscles is estimated.

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Deborah Jump

such as Anderson’s ( 2011 ) “inclusive masculinities” theory would have been welcomed. Indeed, an interrogation of work by Jump ( 2017 ) and Matthews and Channon ( 2017 ) into violence, sport, and praxis was also missing. To surmise, Groombridge suggests that: “sport is not a thing in itself that can

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Anne Delextrat, Sinead Mackessy, Luis Arceo-Rendon, Aaron Scanlan, Roger Ramsbottom and Julio Calleja-Gonzalez

− recently reported in the literature ( Gough et al., 2017 ; McNaughton et al., 2016 ; Sparks et al., 2017 ). Within this context, the aim of this study was to investigate the effects of 3-day serial NaHCO 3 ingestion on repeated sprint and jump ability and physiological parameters during a simulated

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Matthew Ellis, Mark Noon, Tony Myers and Neil Clarke

·kg −1 has been reported to increase jump height, 15-m sprint time, and repeated sprint ability in soccer players. 12 , 13 Approximately 2.6 mg·kg −1 of caffeinated gum has also demonstrated an increase in the distance covered during the Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1). 14 Thus

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Nicola Giovanelli, Filippo Vaccari, Mirco Floreani, Enrico Rejc, Jasmine Copetti, Marco Garra, Lea Biasutti and Stefano Lazzer

conflicting results about the effects of these strategies on performance. 1 Indeed, static stretching, one of the most common strategies used, improves flexibility but can negatively affect the leg press 1 repetition maximum, muscle strength endurance, 20-m sprint performance, and vertical jump height. 2 – 5

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Hayley M. Ericksen, Caitlin Lefevre, Brittney A. Luc-Harkey, Abbey C. Thomas, Phillip A. Gribble and Brian Pietrosimone

previous levels of activity following reconstruction. 2 Aberrant lower-extremity movement biomechanics during dynamic movements have been implicated as a factor increasing the risk of ACL injury. 3 Specifically, the inability to attenuate high forces around the knee during dynamic movements, such as jump

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Daria Neyroud, Jimmy Samararatne, Bengt Kayser and Nicolas Place

seconds. Thereafter, in preparation of the concomitant jumping NMES session, NMES intensity was set to the maximal tolerated intensity while the participants took the squat jump position (ie, knees flexed at 90°). Once determined, participants went back to the ergometer for the measurement of the

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John R. Harry, Leland A. Barker, Jeffrey D. Eggleston and Janet S. Dufek

Many competitive and recreational sports involve a propulsive vertical jump followed by a landing. An unavoidable occurrence during jump landings is impact with the ground. 1 Typically, the landing phase is evaluated with respect to injury potential due to high-magnitude vertical ground reaction

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Angélica Ginés-Díaz, María Teresa Martínez-Romero, Antonio Cejudo, Alba Aparicio-Sarmiento and Pilar Sainz de Baranda

related to a rise of injury risk, not only for catastrophic injuries, but also for overuse. 17 In relation to the most common postures adopted in the different disciplines, show jumping riders use short stirrups in order to adopt the forward riding position needed for jumping. 17 , 18 This posture of