We experimented on task-level robot learning based on bi-directional theory. The via-point representation was used for 'learning by watching'. In our previous work, we had a robot learn kendama (a Japanese game) in order to demonstrate a single simple task. Our approach can be applied to a wide variety of motor behavior. However, some difficulties still remain. In this paper, we address two problems: (1) how to attain a final goal of complex movement when it consists of a sequence of subgoals, and (2) how to adapt to changes in behavior and the environment. To examine how to solve these problems, we propose two methods: (1) selecting the proper via-points for a control variable for each subgoal, and (2) re-estimating the relation between the via-points and the task during learning without conducting extra trials. We adopted a tennis serve and a pendulum upswing for our complicated tasks.
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http://dx.doi.org/10.1016/s0893-6080(98)00062-8 | DOI Listing |
Bioengineering (Basel)
January 2025
Human Performance Laboratory, Centre of Space Bio-Medicine, Department of Medicine Systems, University of Rome Tor Vergata, 00133 Rome, Italy.
Traditional methods for evaluating tennis technique, such as visual observation and video analysis, are often subjective and time consuming. On the other hand, a quick and accurate assessment can provide immediate feedback to players and contribute to technical development, particularly in less experienced athletes. This study aims to validate the use of a single inertial measurement system to assess some relevant technical parameters of amateur players.
View Article and Find Full Text PDFFront Sports Act Living
January 2025
Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.
Background: It is assumed that the tennis serve is performed according to the kinetic chain principle in which a proximal-to-distal sequence in peak angular velocities of subsequent body segments can be observed to reach high end point ball velocities. The aim of the present study was to investigate if the magnitude and (intersegmental) timing of peak angular velocities of body segments in professional tennis players are different between first and second serves and if they are associated with serve performance.
Methods: Eight (two female and six male) professional tennis players performed each 48 tennis serves on a tennis court.
Front Physiol
January 2025
College of Physical Education, Chongqing University, Chongqing, China.
Background: Tennis performance is highly influenced by serve speed. This review aimed to evaluate and quantitatively compare the efficacy of popular strength and conditioning (S&C) training methods in enhancing the speed of the ball in the serves of tennis players.
Methods: Following PRISMA guidelines, a systematic search was conducted in the Scopus, Web of Science, SportsDiscuss, and PubMed databases without date constraints, up to July 2024.
Sensors (Basel)
December 2024
Université de Lyon, UCBL1 Laboratoire Inter Universitaire de Biologie de la Motricité, EA 7424, 69100 Villeurbanne Cedex, France.
This study investigated muscle activation, shocks, and vibrations of the upper extremities during tennis serves between junior and adult tennis players. Thirty-five well-trained tennis players (15 juniors and 20 adults) performed 10 maximal successful tennis serves. Two triaxial accelerometers recorded the shock and vibration on the racket and the hand on the dominant side.
View Article and Find Full Text PDFChildren (Basel)
December 2024
Faculty of Sport Sciences, Universidad Europea de Madrid, 28670 Villaviciosa de Odón, Spain.
Objectives: This study aimed to investigate the effects of external (EXT) versus internal (INT) focus of attention on acquiring and transferring simple and complex motor skills in novice female volleyball players.
Methods: Fifty-seven participants were assigned to one of the three groups: The external focus (EXT), the internal focus (INT), and the control group (CON). Over a 6-week intervention, participants practiced a simple skill (volleyball passing) and a complex skill (overhead tennis serve).
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