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Todd C. Phillips, Sean S. Kohles, John F. Orwin, Lori Thein Brody, Ronald P. McCabe and Ray Vanderby Jr.

An impulse-momentum exercise system was instrumented for collection of kinematic and kinetic data during shoulder exercise. The objective of this study was to quantify the dynamics of an exercise system that utilizes a weighted shuttle (22.2 N) traveling on a rail system and evaluate its efficacy as an exercise and rehabilitative tool. Two healthy adults (mean age. 30.0 years) were tested utilizing 2 protocols. The first protocol required the subject to maintain tension in the system while externally rotating the upper arm from neutral to 90° relative to the shoulder and then internally rotating back to the initial position. In me second protocol, the range of motion was similar, but each subject was instructed to carry out the exercise as rapidly as possible without regard to the tension in the rope, thus creating an impulsive load. Average peak loads up to 87.9 and 137.0 N were recorded using the first and second protocols. respectively. Average maximum loads using the second protocol were approximately 50 N greater than those using the first protocol (p < .05). Representative calculations demonstrated that less mechanical work was performed during the first protocol (−3.8 to −45.9%). Qualitatively the shuttle acceleration curves appear dramatically different, although similar average peak accelerations are achieved during use (4.12 vs. 3.47 m/s2, protocol I vs. protocol 2, respectively).

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Jeffrey M. McBride, Tyler J. Kirby, Tracie L. Haines and Jared Skinner

Purpose:

The purpose of the current investigation was to determine the relationship between relative net vertical impulse (net vertical impulse (VI)) and jump height in the jump squat (JS) going to different squat depths and utilizing various loads.

Methods:

Ten males with two years of jumping experience participated in this investigation (Age: 21.8 ± 1.9 y; Height: 176.9 ± 5.2 cm; Body Mass: 79.0 ± 7.1 kg, 1RM: 131.8 ± 29.5 kg, 1RM/BM: 1.66 ± 0.27). Subjects performed a series of static jumps (SJS) and countermovement jumps (CMJJS) with various loads (Body Mass, 20% of 1RM, 40% of 1RM) in a randomized fashion to a depth of 0.15, 0.30, 0.45, 0.60, and 0.75 m and a self-selected depth. During the concentric phase of each JS, peak force (PF), peak power (PP), jump height (JH) and relative VI were recorded and analyzed.

Results:

Increasing squat depth corresponded to a decrease in PF and an increase in JH, relative VI for both SJS and CMJJS during all loads. Across all squat depths and loading conditions relative VI was statistically significantly correlated to JH in the SJS (r = .8956, P < .0001, power = 1.000) and CMJJS (r = .6007, P < .0001, power = 1.000). Across all squat depths and loading conditions PF was statistically nonsignificantly correlated to JH in the SJS (r = –0.1010, P = .2095, power = 0.2401) and CMJJS (r = –0.0594, P = .4527, power = 0.1131). Across all squat depths and loading conditions peak power (PP) was significantly correlated with JH during both the SJS (r = .6605, P < .0001, power = 1.000) and the CMJJS (r = .6631, P < .0001, power = 1.000). PP was statistically significantly higher at BM in comparison with 20% of 1RM and 40% of 1RM in the SJS and CMJJS across all squat depths.

Conclusions:

Results indicate that relative VI and PP can be used to predict JS performance, regardless of squat depth and loading condition. However, relative VI may be the best predictor of JS performance with PF being the worst predictor of JS performance.

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Aaron T. Scanlan, Neal Wen, Joshua H. Guy, Nathan Elsworthy, Michele Lastella, David B. Pyne, Daniele Conte and Vincent J. Dalbo

basketball players performing power-driven movements during game-play. Furthermore, the IMTP permits assessment of rapid expression of force through various measures including impulse, which is considered the most functional time-dependent measure during isometric contractions. 9 The IMTP has been advocated

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Travis J. Peterson and Jill L. McNitt-Gray

During the golf swing, players must coordinate the legs as one method to regulate linear and angular impulse generation to satisfy the whole-body mechanical objectives. 1 On the course, players also need to modify their address position by changing their lower-extremity configurations to

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John R. Harry, Max R. Paquette, Brian K. Schilling, Leland A. Barker, C. Roger James and Janet S. Dufek

jumpers. 7 This appears to allow for greater 9 and more rapid force production 7 during the concentric phase of the CMVJ. These jumping characteristics may be the underlying mechanism for greater propulsive impulse, which is known to determine CMVJ displacement. 10 The countermovement allows potential

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Ali Jalalvand and Mehrdad Anbarian

fatigue was evaluated with kinetic parameters of landing GRFs, loading rates (rate of force development [RFD]), impulses, and time to peak. The increased magnitude of RFD has been associated with a risk of stress fractures, plantar fasciitis, and patellofemoral pain. 17 As jumping and landing are among

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Toshimasa Yanai, Akifumi Matsuo, Akira Maeda, Hiroki Nakamoto, Mirai Mizutani, Hiroaki Kanehisa and Tetsuo Fukunaga

. All subjects were fully informed of the purpose and the risks of the experiment and gave their written informed consent. Kinetic parameters (force and free moment acting on each leg, and linear and angular impulses exerted on the body) and kinematic parameters (point of force application, CM positions

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AmirAli Jafarnezhadgero, Morteza Madadi-Shad, Christopher McCrum and Kiros Karamanidis

knee abduction and external rotation during landing in genu valgus individuals should be regarded as targets for interventions in these patients ( Barrios et al., 2016 ; Chappell et al., 2007 ). The treatment of knee misalignment might also help to reduce the GRF, vertical loading rate, impulses, and

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Christopher D. Ramos, Melvin Ramey, Rand R. Wilcox and Jill L. McNitt-Gray

momentum by generating linear and angular impulse during interaction with the ground. During the takeoff phase, vertical and horizontal impulse generation requires control of the total body center of mass (CM) trajectory in relation to the reaction forces (RFs) generated during contact with the ground. 1

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

well as peak and mean forces, increase with increasing steady running speed. 9 – 17 Effective vertical impulse, being an integrated value of vertical force representing changes in the center of gravity vertical velocity within a specific duration, increases up to moderate speed with increasing steady