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Uri, O., Pritsch, M., Oran, A., & Liebermann, D. G. (2014). Upper limb kinematics after arthroscopic and open shoulder stabilization. Journal of Shoulder and Elbow Surgery, .
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Tenenbaum, G., Kohler, N., Shraga, S., Liebermann, D. G., & Lidor, R. (1996). Anticipation and confidence of decisions related to skilled performance. Journal of Sport Psychology, 27, 293–307.
Abstract: This study was carried out to examine anticipatory decisions of novice, intermediate, and expert tennis players and the confidence with which these decisions are made by these athletes. Perceived eye-focus was also measured to verify whether it is related to expertise level prior to action execution. Forty-five Australian players, 15 in each skill category, were exposed to 6 temporal occluded film conditions (480, 320, 160 ms prior to racquet-ball contact, at contact, and 160 and 320 ms after contact) in randomized order within 8 tennis strokes. In each condition, after viewing the filmed sequence, they were asked to report the final ball location of the opponent's stroke, how confident they were in this decision, and their perceived eye-focus location during the sequence. Experts and intermediates were superior in anticipatory decisions to their counterparts, only under short exposure durations. Novices showed more confidence than experts and intermediates at the beginning of the sequence, but after 160 and 320 ms of ball-racquet contact, experts were much more confident than novices, and intermediates. Self-reported eye-focus differed substantially with respect to expertise level. While experts attended to several locations prior to ball-racquet contact, intermediate and novice players gazed at one location. After contact, the reverse was evident. The findings are in partial agreement with other studies which have applied the temporal occlusion paradigm to study expert-novice differences in anticipatory skills.
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Liebermann, D. G., Katz, L., Hughes, M. D., Bartlett, R. M., McClements, J., & Franks, I. M. (2002). Advances in the application of information technology to sport performance. J Sports Sci, 20(10), 755–769.
Abstract: This paper overviews the diverse information technologies that are used to provide athletes with relevant feedback. Examples taken from various sports are used to illustrate selected applications of technology-based feedback. Several feedback systems are discussed, including vision, audition and proprioception. Each technology described here is based on the assumption that feedback would eventually enhance skill acquisition and sport performance and, as such, its usefulness to athletes and coaches in training is critically evaluated.
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Issurin, V. B., Liebermann, D. G., & Tenenbaum, G. (1994). Effect of vibratory stimulation training on maximal force and flexibility (Vol. 12).
Abstract: In this study, we investigated a new method of training for maximal strength and flexibility, which included exertion with superimposed vibration (vibratory stimulation, VS) on target muscles. Twenty-eight male athletes were divided into three groups, and trained three times a week for 3 weeks in one of the following conditions: (A) conventional exercises for strength of the arms and VS stretching exercises for the legs; (B) VS strength exercises for the arms and conventional stretching exercises for the legs; (C) irrelevant training (control group). The vibration was applied at 44 Hz while its amplitude was 3 mm. The effect of training was evaluated by means of isotonic maximal force, heel-to-heel length in the two-leg split across, and flex-and-reach test for body flexion. The VS strength training yielded an average increase in isotonic maximal strength of 49.8%, compared with an average gain of 16% with conventional training, while no gain was observed for the control group. The VS flexibility training resulted in an average gain in the legs split of 14.5 cm compared with 4.1 cm for the conventional training and 2 cm for the control groups, respectively. The ANOVA revealed significant pre-post training effects and an interaction between pre-post training and 'treatment' effects (P < 0.001) for the isotonic maximal force and both flexibility tests. It was concluded that superimposed vibrations applied for short periods allow for increased gains in maximal strength and flexibility.
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Friedman, J., Raveh, E., Weiss, T., Itkin, S., Niv, D., Hani, M., et al. (2019). Applying Incongruent Visual-Tactile Stimuli during Object Transfer with Vibro-Tactile Feedback (Vol. 147).
Abstract: The application of incongruent sensory signals that involves disrupted tactile feedback is rarely explored, specifically with the presence of vibrotactile feedback (VTF). This protocol aims to test the effect of VTF on the response to incongruent visual-tactile stimuli. The tactile feedback is acquired by grasping a block and moving it across a partition. The visual feedback is a real-time virtual presentation of the moving block, acquired using a motion capture system. The congruent feedback is the reliable presentation of the movement of the block, so that the subject feels that the block is grasped and see it move along with the path of the hand. The incongruent feedback appears as the movement of the block diverts from the actual movement path, so that it seems to drop from the hand when it is actually still held by the subject, thereby contradicting the tactile feedback. Twenty subjects (age 30.2 +/- 16.3) repeated 16 block transfers, while their hand was hidden. These were repeated with VTF and without VTF (total of 32 block transfers). Incongruent stimuli were presented randomly twice within the 16 repetitions in each condition (with and without VTF). Each subject was asked to rate the difficulty level of performing the task with and without the VTF. There were no statistically significant differences in the length of the hand paths and durations between transfers recorded with congruent and incongruent visual-tactile signals – with and without the VTF. The perceived difficulty level of performing the task with the VTF significantly correlated with the normalized path length of the block with VTF (r = 0.675, p = 0.002). This setup is used to quantify the additive or reductive value of VTF during motor function that involves incongruent visual-tactile stimuli. Possible applications are prosthetics design, smart sport-wear, or any other garments that incorporate VTF.
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