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Tom G. Welter and Maarten F. Bobbert

It has been shown in previous research that the initial phase of EMG for a punching movement remained almost unchanged regardless of whether an external force was applied to the arm. The purpose of the present study was to explain this finding with the help of simulations. A two-dimensional model of me arm actuated by 6 Hill-type muscles was used to simulate a punching movement in the horizontal plane from a prescribed starting position with 90° elbow flexion. Input to the model was the stimulation of me muscles, and output were, among others, muscle forces and segmental accelerations. A genetic algorithm was used to determine the muscle onset times mat minimized movement duration and targeting error. In a subsequent forward simulation, the optimized muscle onset times for an unloaded punching movement were superimposed on the isometric stimulation necessary to hold me arm in the starting position while an external force was applied to the arm. The resulting movement was only slightly different from the unloaded movement. It appeared that because of the low level of isometric muscle force prior to the movement, and the high level of stimulation during the movement, muscle force was increased at a rate mat was almost independent of the prior force level. These results confirmed the suggestion that the initial phase of EMG in ballistic movements is more related to the rate of change of force than to the absolute force level. It is hypothesized mat this may simplify the task of the nervous system in the choice of initial muscle activity in ballistic arm movements because no adjustments to varying external forces are required.

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Chelsey Klimek, Christopher Ashbeck, Alexander J. Brook, and Chris Durall

CrossFit gym using successive and rapid ballistic movements with minimal to no recovery time between movements. A wide variety of high-intensity exercises that include running, rowing, Olympic lifting, powerlifting, and gymnastic exercises were included in the CrossFit training. A physical fitness training

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Brandon Rohrer, Susan Fasoli, Hermano Igo Krebs, Bruce Volpe, Walter R Frontera, Joel Stein, and Neville Hogan

Submovements are hypothesized building blocks of human movement, discrete ballistic movements of which more complex movements are composed. Using a novel algorithm, submovements were extracted from the point-to-point movements of 41 persons recovering from stroke. Analysis of the extracted submovements showed that, over the course of therapy, patients' submovements tended to increase in peak speed and duration. The number of submovements employed to produce a given movement decreased. The time between the peaks of adjacent submovements decreased for inpatients (those less than 1 month post-stroke), but not for outpatients (those greater than 12 months post-stroke) as a group. Submovements became more overlapped for all patients, but more markedly for inpatients. The strength and consistency with which it quantified patients' recovery indicates that analysis of submovement overlap might be a useful tool for measuring learning or other changes in motor behavior in future human movement studies.

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Stephen M. Suydam, Kurt Manal, and Thomas S. Buchanan

the underlying motor units to change, which imposes signal variability. 24 Ballistic movements also require a different recruitment pattern than those of MVIC. 25 The possibility of changing recruitment patterns during motion may result in unreliable signals. Ballistic movements require rapid

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Roland van den Tillaar

and are perhaps not suitable for ballistic movements (involve several joint movements with maximal effort) that often are used like a shooting task in stick sports (hockey, ice hockey, and floorball). In other ballistic movements, such as throwing ( Indermill & Husak, 1984 ; van den Tillaar & Ettema

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Mark G.L. Sayers and Stephen Bishop

players . J Strength Cond Res. 2016 ; 30 ( 4 ), 1118 – 1126 . PubMed doi: 10.1519/JSC.0b013e3182a1da46 23838968 10.1519/JSC.0b013e3182a1da46 15. Samozino P , Rejc E , Di Prampero PE , et al . Optimal force-velocity profile in ballistic movements--altius: citius or fortius? Med Sci Sports

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Lucas C. Bianco, James M. May, Smokey L. Fermin, Robert Oates, and Scott W. Cheatham

or degenerative changes of the tendon. 1 , 2 , 4 , 5 The main symptom used to diagnose patella tendinopathy is insidious anterior knee pain related to repetitive sudden ballistic movements. 4 Patella tendinopathy is referenced to as jumper’s knee because of the prevalence of patella tendon pain in

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Ran Zheng, Ilana D. Naiman, Jessica Skultety, Steven R. Passmore, Jim Lyons, and Cheryl M. Glazebrook

). Startle reveals independent preparation and initiation of triphasic EMG burst components in targeted ballistic movements . Journal of Neurophysiology, 110 ( 9 ), 2129 – 2139 . PubMed ID: 23926044 doi:10.1152/jn.00888.2012 10.1152/jn.00888.2012 Fournier , K.A , Hass , C.J. , Naik , S.K. , Lodha