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Deborah L. Feltz, Norbert L. Kerr and Brandon C. Irwin

The present investigation examined the Köhler motivation gain effect in a health game using an absent partner, presented virtually. The Köhler effect occurs when an inferior team member performs a difficult task better in a team or coaction situation than one would expect from knowledge of his or her individual performance. The effect has been strongest in conjunctive task conditions in which the group’s potential productivity is equal to the productivity of its least capable member. Participants were randomly assigned to one of four conditions (individual control, coaction, additive, and conjunctive) in a 4 (conditions) × 2 (gender) factorial design and performed a series of isometric plank exercises within an exercise game. They performed the first series of five exercises alone holding each position for as long as they could, and, after a rest period, those in the partner conditions were told they would do remaining trials with a same-sex virtual partner whom they could observe during their performance. The partner’s performance was manipulated to be always superior to the participant’s. Results showed that task persistence was significantly greater in all experimental conditions than in the individual control condition. The conjunctive condition was no more motivating than either the additive or coactive conditions. Results suggest that working out with virtually present, superior partners can improve persistence motivation on exercise game tasks.

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Joel R. Martin, Mark L. Latash and Vladimir M. Zatsiorsky

This study investigated the effects of modifying contact finger forces in one direction—normal or tangential—on the entire set of the contact forces, while statically holding an object. Subjects grasped a handle instrumented with finger force-moment sensors, maintained it at rest in the air, and then slowly: (1) increased the grasping force, (2) tried to spread fingers apart, and (3) tried to squeeze fingers together. Analysis was mostly performed at the virtual finger (VF) level (the VF is an imaginable finger that generates the same force and moment as the four fingers combined). For all three tasks there were statistically significant changes in the VF normal and tangential forces. For finger spreading/squeezing the tangential force neutral point was located between the index and middle fingers. We conclude that the internal forces are regulated as a whole, including adjustments in both normal and tangential force, instead of only a subset of forces (normal or tangential). The effects of such factors as EFFORT and TORQUE were additive; their interaction was not statistically significant, thus supporting the principle of superposition in human prehension.

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Sukhvinder S. Obhi, Patrick Haggard, John Taylor and Alvaro Pascual-Leone

Bimanual coordination tasks form an essential part of our behaviour. One brain region thought to be involved in bimanual coordination is the supplementary motor area (SMA). We used repetitive transcranial magnetic stimulation (rTMS) at 1 Hz for 5 min to create a temporary virtual lesion of the rostral portion of the human SMA immediately prior to performance of a goal-directed bimanual coordination task. In two control conditions, participants underwent sham stimulation or stimulation over the primary motor cortex (MI). The experimental task was to open a drawer with the left hand, catch a ball with the right hand, and reinsert the ball into the drawer through an aperture just big enough for the ball to pass through, again with the right hand. Hence, the actions of one hand depend upon the actions of the other. We calculated time intervals between the successive component actions of one hand (unimanual intervals) and actions of both hands (bimanual intervals) and analyzed these intervals separately. Interestingly, none of the unimanual intervals were affected by the rTMS, but the variability of a critical bimanual interval—the time between the left hand opening the drawer and the right hand starting to move to catch the ball—was increased by rTMS over the rostral parts of the SMA. No such effect was seen following rTMS over MI or after sham rTMS. Our results suggest that the rostral parts of the SMA play an important role in aspects of functional bimanual tasks, which involve tight temporal coordination between different motor actions of the two hands.

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Noah X. Tocci, David R. Howell, Dai Sugimoto, Corey Dawkins, Amy Whited and Donald Bae

Coordinate System Definitions The pelvis local coordinate system was defined as follows: origin, Pelvis_Origin virtual marker; longitudinal axis, a vector extending from the Pelvis_Origin to the mid_Hip virtual marker; mediolateral axis, a vector extending from the Pelvis_Origin to the sacrum marker; and

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Bart Roelands and Kevin De Pauw

. Artificial intelligence experts have been working on the implementation of virtual-, augmented-, and mixed-reality sessions into the microcycle planning of athletes. These strategies seemed science fiction only a few years ago but are now being used in tactical training sessions. The integration of

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Carlo Massaroni, Eugenio Cassetta and Sergio Silvestri

, to the best of our knowledge, the unique validated model for respiratory computation, it appears to be affected by some weaknesses: (i) it cannot be used in other motion capture systems; (ii) extra virtual markers are required to close the chest wall surface and calculate respiratory volumes (leading

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Yi-Ching Chen, I-Chen Lin, Yen-Ting Lin, Wei-Min Huang, Chien-Chun Huang and Ing-Shiou Hwang

% MVC on the monitor during CT by resisting virtual perturbation of a 0.2-Hz sinusoidal signal (Figure  1 , the lower plot). Being blinded to the virtual perturbation that deviated force output, the participants had to carefully monitor the tracking mismatch at every moment. Actually, the participants

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Denny Meyer, Madawa W. Jayawar, Samuel Muir, David Ho and Olivia Sackett

outcome measures. Methods Virgin Pulse is a global software as a service vendor addressing the need for workplace programs that encourage increased physical activity and improved nutrition. One of the Virgin Pulse programs called the Global Challenge (VPGC) consists of a 100-day virtual journey during

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Lauren C. Benson, Stephen C. Cobb, Allison S. Hyngstrom, Kevin G. Keenan, Jake Luo and Kristian M. O’Connor

cluster was used to determine the locations of the second metatarsal head and the distal end of the shoe during the movement trials, using a modification of the virtual marker representation outlined by Nagano et al. 11 Based on the assumption that the shoe is rigid during the swing phase, particularly

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Arturo Forner-Cordero, Virgínia H. Quadrado, Sitsofe A. Tsagbey and Bouwien C.M. Smits-Engelsman

how the errors are reduced while performing the task under these new conditions. Examples of experimental modifications of task conditions are visual distortion or virtual force fields ( Blanchette & Bouyer, 2009 ; Inui & Hatta, 2002 ; Krakauer & Mazzoni, 2011 ; Lackner & DiZio, 2005 ; Shadmehr