Christian Stockinger

The BioMotionBot: a robotic device for applications in human motor learning and rehabilitation.

Robotic manipulanda are an established tool for the investigation of human motor control and learning. Potentially, robotic manipulanda could also be valuable in the investigation of skill learning in more natural movement tasks. Most current designs have been developed for studying dynamic learning and rehabilitation and are restricted to 2D space. However, natural upper limb movements take place in 3D space, sometimes with high underlying forces. In this paper, we introduce a robotic device, the BioMotionBot, that can be used in established applications of dynamic learning and rehabilitation but also enables the investigation of skill learning in more natural 3D movement tasks with large dynamic perturbations. The design of the BioMotionBot is based on a mechanism with hybrid serial and parallel kinematics. We first describe the BioMotionBots mechanical design, the electronic components, the software structure and the control system. To investigate the performance of the BioMotionBot, its stiffness, endpoint mass, endpoint viscosity, haptic resolution, force depth and impedance ratio are evaluated. Additionally, we develop a detailed multi-body simulation model to validate aspects of the structure and behavior of the BioMotionBot. Finally, we present experimental data from a dynamic learning task in 2D and test a 3D scenario with virtual walls. Our results demonstrate that the BioMotionBot can be used for research in human motor learning and rehabilitation and also has potential for the investigation of skill learning in more natural 3D movement tasks.

The kinetics of blood lactate in boys during and following a single and repeated all-out sprints of cycling are different than in men.

This study characterized the impact of high-intensity interval training on the kinetics of blood lactate and performance in trained boys and men. Twenty-one boys (11.4 ± 0.8 years) and 19 men (29.4 ± 5.0 years) performed a set of four 30-s sprints with 2-min of rest and a single 30-s sprint on 2 separate occasions (randomized order) with assessment of performance. Blood lactate was assayed after each sprint and during 30 min of recovery from both tests. The individual time-curves of blood lactate concentration were fitted to the biexponential function as follows: [Formula: see text], where the velocity parameters γ1 and γ2 reflect the capacity to release lactate from the previously active muscle into the blood and to subsequently eliminate lactate from the organism, respectively. In both tests, peak blood lactate concentration was significantly lower in the boys (four 30-s sprints: 12.2 ± 3.6 mmol·L(-1); single 30-s sprint: 8.7 ± 1.8 mmol·L(-1)) than men (four 30-s sprints: 16.1 ± 3.3 mmol·L(-1); single 30-s sprint: 11.5 ± 2.1; p < 0.001). The boys exhibited faster γ1 (1.4531 ± 0.65 min; p < 0.001) and γ2 (0.059 ± 0.023 min; p = 0.01) in the single 30-s sprint and faster γ2 (0.049 ± 0.016 min; p = 0.01) in the four 30-s sprints. The worsening of performance from the first to the last of the four 30-s sprints was less pronounced in boys (9.2% ± 13.9%) than men (19.2% ± 11.5%; p = 0.01). In the present study boys, when compared with men, exhibited lower Peak blood lactate concentration; less pronounced decline in performance during the sprints concomitantly with more rapid release and elimination during the single 30-s sprint; and faster elimination of lactate following the four 30-s sprints.

Consecutive learning of opposing unimanual motor tasks using the right arm followed by the left arm causes intermanual interference

Intermanual transfer (motor memory generalization across arms) and motor memory interference (impairment of retest performance in consecutive motor learning) are well-investigated motor learning phenomena. However, the interplay of these phenomena remains elusive, i.e., whether intermanual interference occurs when two unimanual tasks are consecutively learned using different arms. Here, we examine intermanual interference when subjects consecutively adapt their right and left arm movements to novel dynamics. We considered two force field tasks A and B which were of the same structure but mirrored orientation (B = -A). The first test group (ABA-group) consecutively learned task A using their right arm and task B using their left arm before being retested for task A with their right arm. Another test group (AAA-group) learned only task A in the same right-left-right arm schedule. Control subjects learned task A using their right arm without intermediate left arm learning. All groups were able to adapt their right arm movements to force field A and both test groups showed significant intermanual transfer of this initial learning to the contralateral left arm of 21.9% (ABA-group) and 27.6% (AAA-group). Consecutively, both test groups adapted their left arm movements to force field B (ABA-group) or force field A (AAA-group). For the ABA-group, left arm learning caused significant intermanual interference of the initially learned right arm task (68.3% performance decrease). The performance decrease of the AAA-group (10.2%) did not differ from controls (15.5%). These findings suggest that motor control and learning of right and left arm movements involve partly similar neural networks or underlie a vital interhemispheric connectivity. Moreover, our results suggest a preferred internal task representation in extrinsic Cartesian-based coordinates rather than in intrinsic joint-based coordinates because interference was absent when learning was performed in extrinsically equivalent fashion (AAA-group) but interference occurred when learning was performed in intrinsically equivalent fashion (ABA-group).

Mechanisms within the Parietal Cortex Correlate with the Benefits of Random Practice in Motor Adaptation

The motor learning literature shows an increased retest or transfer performance after practicing under unstable (random) conditions. This random practice effect (also known as contextual interference effect) is frequently investigated on the behavioral level and discussed in the context of mechanisms of the dorsolateral prefrontal cortex and increased cognitive efforts during movement planning. However, there is a lack of studies examining the random practice effect in motor adaptation tasks and, in general, the underlying neural processes of the random practice effect are not fully understood. We tested 24 right-handed human subjects performing a reaching task using a robotic manipulandum. Subjects learned to adapt either to a blocked or a random schedule of different force field perturbations while subjects’ electroencephalography (EEG) was recorded. The behavioral results showed a distinct random practice effect in terms of a more stabilized retest performance of the random compared to the blocked practicing group. Further analyses showed that this effect correlates with changes in the alpha band power in electrodes over parietal areas. We conclude that the random practice effect in this study is facilitated by mechanisms within the parietal cortex during movement execution which might reflect online feedback mechanisms.

Bilateral practice improves dominant leg performance in long jump

Abstract Benefits of bilateral practice both for the non-dominant and for the dominant body side have been shown in several studies. Thereby, most of the studies included movement tasks of the upper extremity or investigated sports games in which the ability of acting bilaterally is an essential basis for success and, thus, a bilateral practice is reasonable anyway. Individual unilaterally performed sports including movement tasks of the lower extremity are rarely investigated. Therefore, the aim of our study was to test if contralateral transfer due to bilateral practice can be found in an unilaterally performed sport including the lower extremity. We trained and tested 61 adolescent athletes in long jump to compare the jumping performance of the dominant leg after a 12-week practice period between two groups: a bilateral practice group that practiced specific long jump exercises with both the dominant and non-dominant leg and an unilateral practice group that practiced specific long jump exercises only with the dominant leg. Results showed a superior effect of bilateral practice compared to unilateral practice regarding the jumping performance of the dominant leg. The performance increase at post-test and retention-test for the dominant limb was significantly higher for the bilateral practice group (pre-to-post: 5.2%, pre-to-retention: 7.4%) compared to the unilateral practice group (pre-to-post: 3.4%, pre-to-retention: 4.5%). Thus, bilateral practice should be established in the early practice programmes of track and field athletes to improve the performance of the dominant take-off leg.

Effects of Compression Garments on Performance and Recovery in Endurance Athletes

Athletes specializing in different endurance sports at various levels of performance wear compression garments to improve their performance and facilitate recovery. The purpose of this chapter is outline the effects of compression garments on performance and recovery in endurance disciplines. A computerized research of the electronic databases PubMed, MEDLINE, SPORTDiscus, and Web of Science (performed in December 2015) and articles published in peer-reviewed journals were analyzed. Studies examining effects on performance, recovery, physiological, and/or psychological parameters during or after endurance sports comparing experimental (compression) and control (non-compression) trials were investigated. A total of 55 articles involving 788 participants were included. Compression garments exerted no significant improvements on performance in running (400 m–42.195 km), triathlon, ice speed skating, cross country skiing, and kayaking. Maximal and submaximal oxygen uptake, blood lactate concentrations, blood gas analysis, cardiac parameters, and body temperature were not altered in most of the considered studies during endurance exercise. Also in most studies, perceived exertion as well as perceived temperature were not affected by compression. Compression clothing significantly increased cycling performance, post exercise blood lactate elimination and reductions in blood lactate concentration during running, cycling, and cross country skiing. Three studies observed improved muscular oxygenation following and during endurance exercise. Furthermore, compression garments reduced post-exercise muscle soreness following running and cycling in eight studies. We conclude that compression clothing has no significant impact on performance parameters during running, ice speed skating, triathlon, cross country skiing and kayaking. The wearing of compression clothing might improve cycling performance, reduce post-exercise muscle pain following running and cycling, and facilitate lactate elimination during recovery.