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The float serve is an effective weapon to impede the attack of the opposing team. Because of its great importance in indoor and beach volleyball, we measured and quantified the float effect. We recorded 24 float serves of 12 top athletes in beach volleyball and indoor volleyball, respectively, and analyzed them using video analysis. We determined the 3D trajectories of the ball flight and developed two measures to describe the size of the float effect, the mean residuals and the anticipation error. Both were derived from regression models. These measures suggest that the float effect is greater in the vertical plane than in the horizontal plane, both for indoor and beach volleyball. Analyses of ball release velocities suggest that a certain ball release velocity is a necessary, but not sufficient, condition for ball floating. A validation of the float measurements with subjective expert ratings showed a correlation with the horizontal deviations. This study provides a new approach to analyze floating in on-court volleyball serves and broadens the knowledge for float effects in sports.
Inhibition is a central component of human behavior. It enables flexible and adaptive behavior by suppressing prepotent motor responses. In former studies, it has been shown that sport athletes acting in dynamic environments exhibit superior motor inhibitory control based on sensory stimuli. So far, existing studies have corroborated this in manual motor response settings only. Therefore, this study addresses the effector specificity of the inhibition benefit in elite athletes compared to physically active controls. A sport-unspecific stop-signal task has been adapted for hand as well as feet usage and 30 elite handball players as well as 30 controls were tested. A repeated-measures ANOVA with the two factors “effector” (hands, feet) and “group” (expert, recreational athletes) was conducted. Our results suggest no group differences in two-choice response times, but a convincing superiority of handball players in inhibitory control (i.e., shorter stop-signal reaction times), predominantly when responding with their hands, with weaker differential effects when responding with their feet. This suggests that motor inhibition might be a comprehensive performance characteristic of sport athletes acting in dynamic environments, detectable predominantly in eye-hand coordination tasks.
Multitasking is ubiquitous in our everyday life. Accordingly, situations in which two or more tasks need to be handled concurrently or in close temporal succession have been studied intensely. Different paradigms have been developed in that context (Koch et al., 2018). Over the last decades, the psychological refractory period (PRP) paradigm has dominated dual-task research, because it allows quantitative predictions of reaction time increases coupled to stimulus onset asynchrony. Part of the success of this paradigm is grounded in the fact that most of the studies are run under strict experimental control with very elementary tasks, mostly characterized by a definite start and ending. However, it remains unclear whether these limited settings sufficiently reflect the range of eventualities we find in real life. Rather, there is accumulating evidence that important factors modulating multitask performance are not sufficiently captured by the PRP approach. Here we focus on evidence that motor responses that involve continuous interaction with the environment may engage processes that alter the coordination of concurrently performed tasks in fundamental ways. ...
Highlights
• Investigation of how the peripheral muscle system responds to imagination in interaction with proprioceptive information.
• Motor imagery altered time to contraction but not velocity and maximal displacement of the muscle belly.
• Findings indicate that MI might impact on the initiation of contraction.
Abstract
Many studies have investigated the activation of cortical areas and corticospinal excitability during motor imagery (MI) in relation to motor execution. Similar activation of cortical areas during imagined and executed bodily movements and increased corticospinal excitability while imagining movements has been demonstrated. Despite these similarities on the central nervous system level, there is no overt movement during MI. This suggests that centrally generated signals must be inhibited at some level. Second, even in the absence of movement, some studies find behavioral effects of MI interventions. Most of the studies have investigated the role of MI on the cortical or spinal level, but less is known about the peripheral level, such as the muscle system. Testing muscular excitability during MI will give further hints whether and how low-threshold motor commands during MI reach the muscular system. Furthermore, the extent of the shown effects during imagery depends considerably on type of imagery, available proprioceptive information, and imagery ability. Therefore, this study investigates muscular excitability of the biceps brachii muscle manipulating imagery mode (MI vs. visual imagery) and proprioceptive information (with or without muscle effort). 40 participants were included in the analysis. The mechanical response of the muscle after a single electrical stimulus was assessed via tensiomyography. The corresponding variables maximal displacement, delay time, and contraction velocity were used to calculate 2 × 2 ANOVAs with repeated measurements. The absence of interaction effects shows that possible imagery effects on the muscle system are not increased by effort. MI altered time to contraction with lower delay time compared to control condition. Velocity and maximal displacement of the muscle belly during contraction did not differ between imagery conditions. This indicates that MI might impact on the initiation of muscle contraction but does not change the contraction itself. Thus, neuronal factors are moving further into focus in the context of MI research.
The relationship between external and internal load parameters in 3 × 3 basketball tournaments
(2022)
Purpose: 3 × 3 basketball games are characterized by high-intensity accelerations and decelerations, and a high number of changes of direction and jumps. It is played in tournament form with multiple games per day. Therefore, optimal regeneration is crucial for maintaining a high performance level over the course of the tournament. To elucidate how load of a match affects the athletes' bodies (i.e., internal load), muscular responses to the load of 3 × 3 games were analyzed. We aimed to investigate changes in contractility of the m. rectus femoris (RF) and m. gastrocnemius medialis (GC) in response to the load of single 3 × 3 games and a 3 × 3 tournament.
Methods: Inertial movement analysis was conducted to capture game load in 3 × 3. Changes in contractility were measured using tensiomyography (TMG). During a two-day tournament, TMG measurements were conducted in the morning and after each game. Additionally, off-game performance analysis consisting of jump and change-of-direction (COD) tests was conducted the day before the tournament.
Results: Significant changes of the muscle contractility were found for GC with TMG values being higher in the baseline than in the post-game measurements. In contrast to athletes of the GC group, athletes of the RF group responded with either decreased or increased muscle contractility after a single 3 × 3 game. A significant correlation between external and internal load parameters could not be shown. Concerning off-game performance, significant correlations can be reported for COD test duration, CMJ height and ∆Vc as well as COD test duration and ∆Dm. No systematic changes in muscle contractility were found over the course of the tournament in RF and GC.
Conclusion: The athletes' external 3 × 3 game load and their performance level did not seem to affect muscular contractility after a single 3 × 3 game or a complete 3 × 3 tournament within this investigation. This might indicate that elite athletes can resist external load without relevant local muscular fatigue. With respect to the course of the tournament, it can therefore be concluded that the breaks between games seem to be sufficient to return to the initial level of muscle contractility.