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Claire J Brady, Andrew J Harrison, Eamonn P Flanagan, G Gregory Haff and Thomas M Comyns

Purpose:

This investigation examined the relationships between the isometric mid-thigh pull (IMTP), isometric squat (ISqT) and sprint acceleration performance in track & field sprinters, and to determine whether there are differences between males and females.

Methods:

Fifteen male and ten female sprinters performed 3 maximal effort IMTPs, ISqTs and 3 x 30 m from blocks.

Results:

Among males, results showed significant negative correlations between IMTP and ISqT peak force, relative peak force, force at 100, 150 and 200 ms, rate of force development (0 – 150, 0 – 200 ms) and impulse (0 – 200 ms) and 0 – 5 m time (r = -0.517 to -0.714; P < 0.05). IMTP impulse significantly predicted 0 – 5 m time (B = -0.582, P = 0.023). ISqT relative peak force significantly predicted 0 – 5 m time (B = -0.606, P = 0.017). Among females, no IMTP or ISqT variables significantly correlated with any sprint times. Males measured significantly higher than females for all IMTP measures except for relative peak force. Males were significantly faster than females at all splits. When comparing measures of the ISqT, there were no significant differences between males and females.

Conclusions:

Variables measured during the IMTP and ISqT significantly correlated with 0 – 5 m sprint performance in male athletes. Isometric strength can have a sizable influence on 0 – 5 m time, but in some cases the maximum effect could be very small.

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D.S. Blaise Williams III, Jonathan H. Cole and Douglas W. Powell

Running during sports and for physical activity often requires changes in velocity through acceleration and deceleration. While it is clear that lower extremity biomechanics vary during these accelerations and decelerations, the work requirements of the individual joints are not well understood. The purpose of this investigation was to measure the sagittal plane mechanical work of the individual lower extremity joints during acceleration, deceleration, and steady-state running. Ten runners were compared during acceleration, deceleration, and steady-state running using three-dimensional kinematics and kinetics measures. Total positive and negative joint work, and relative joint contributions to total work were compared between conditions. Total positive work progressively increased from deceleration to acceleration. This was due to greater ankle joint work during acceleration. While there was no significant change in total negative work during deceleration, there was a greater relative contribution of the knee to total negative work with a subsequent lower relative ankle negative work. Each lower extremity joint exhibits distinct functional roles in acceleration compared with deceleration during level running. Deceleration is dominated by greater contributions of the knee to negative work while acceleration is associated with a greater ankle contribution to positive work.

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Logan A. Lucas, Benjamin S. England, Travis W. Mason, Christopher R. Lanning, Taylor M. Miller, Alexander M. Morgan and Thomas Gus Almonroeder

3 times an athlete’s body weight. 7 These impact forces generate a transient spike in acceleration which is transmitted throughout the musculoskeletal system from the foot to the head. 8 Although the lower-extremity musculature can help to attenuate these impact accelerations, passive tissues also

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David S. Haydon, Ross A. Pinder, Paul N. Grimshaw and William S.P. Robertson

classifications, 1 as well as performance outcomes. 2 Despite an increase in popularity and research in wheelchair rugby (WCR), there is currently a limited understanding of how the level of activity limitation affects key kinematic variables and their impact on chair acceleration and sprint performance

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Mohsen Shafizadeh, Nicola Theis and Keith Davids

, since the capacity of certain tissues to transmit and attenuate shock may be frequency dependent ( Smeathers, 1989 ). The frequency content and signal power of impact shock and tibia acceleration during stance phase of normal running are thought to be governed primarily by movement of the leg and center

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Heidi R. Thornton, Jace A. Delaney, Grant M. Duthie and Ben J. Dascombe

During the same training camp, 9 a research abstract showed that an increased acceleration/deceleration load (SumAccDec) was associated with very likely small increases in sleep duration (effect size [ES] = 0.27; ±0.16), time in bed (TIB; ES = 0.25; ±0.16), and sleep-onset latency (ES = 0.20; ±0

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Ted Polglaze and Matthias W. Hoppe

demands of brief, nonsteady-state—and often high-intensity—accelerations cannot be directly measured. However, this is possible for steady-state incline running, where energy cost increases with slope but, as per running on level ground, is independent of speed at a given slope. 5 Accordingly

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Ryu Nagahara, Mirai Mizutani, Akifumi Matsuo, Hiroaki Kanehisa and Tetsuo Fukunaga

preceding acceleration. In contrast, Morin et al 6 and Rabita et al 8 found no significant relationship between averaged vertical force or impulse over a 40-m distance and either maximal speed or mean running speed over 40 m. They demonstrated that a larger propulsive force or impulse during the

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Aaron T. Scanlan, Robert Stanton, Charli Sargent, Cody O’Grady, Michele Lastella and Jordan L. Fox

max ]) 4 demands while undertaking extensive physical requirements, including jumping (1.1 per min), accelerations (∼60), and change-of-direction movements (∼180) during game-play. 6 Despite the growing body of descriptive evidence quantifying game demands in basketball, the impact of overtime

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Lydia R. Vollavanh, Kathleen M. O’Day, Elizabeth M. Koehling, James M. May, Katherine M. Breedlove, Evan L. Breedlove, Eric A. Nauman, Debbie A. Bradney, J. Eric Goff and Thomas G. Bowman

rotational accelerations based on player position, event type, and location of impact in football. 7 , 16 Researchers also noted differences in mechanism, event type, and location of impact in youth and collegiate ice hockey. 4 , 14 To date, research into head impacts in men’s lacrosse is limited. 25 The