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Single Degree-of-Freedom Undamped Vibration
Published in Haym Benaroya, Mark Nagurka, Seon Han, Mechanical Vibration, 2017
Haym Benaroya, Mark Nagurka, Seon Han
METRONOME. A metronome is an instrument that produces regularly timed click sounds at a fixed number of beats per minute (BPM). It is used by musicians as they practice playing any instrument, such as a guitar, piano, clarinet, etc.
Mixed-reality human-machine-interface for motor learning of physical activities
Published in Advanced Robotics, 2022
Sebastian Chinchilla Gutierrez, Jose Salazar, Yasuhisa Hirata
The first contribution of this work consists of developing an automatic training method that allows the user to retain motor skills. After having completed training with the system for 30 min, subjects are able to reduce their position and velocity trajectory error compared to people who did not use it. Secondly, a method for multimodally conveying velocity, position, and tempo of the motion was developed. While a metronome conveys tempo, wearable vibroactuators transmit velocity and tempo, and a floor projection provides feedback of velocity and position. Finally, based on the system, an application for teaching the footwork of ballroom dance was developed. As a result, we observed that users can follow the feedback and retain the skills after finishing training.
Does ankle joint flexibility affect underwater kicking efficiency and three-dimensional kinematics?
Published in Journal of Sports Sciences, 2019
Hirofumi Shimojo, Rio Nara, Yasuhiro Baba, Hiroshi Ichikawa, Yusuke Ikeda, Yoshimitsu Shimoyama
Previous studies have shown a positive association between kicking frequency and velocity in UUS (Connaboy et al., 2009). Furthermore, with a constant kicking frequency while swimming, there is a constant power output in the human leg kick (Zamparo, Pendergast, Termin, & Minetti, 2002). A previous study suggested imposing a kicking frequency control of UUS to 85% (Shimojo et al., 2014; Yamakawa et al., 2017). Thus, 80% kicking frequency of UUS was calculated according to the swimmers’ 100% kicking frequency, and this tempo was set in a waterproof metronome device (Tempo Trainer®; FINIS Inc., USA). This condition helps swimmers to not change the kicking frequency following the main trials and prevents ankle joint injury. After familiarising with the metronome device during UUS, in all subsequent trials, the swimmers synchronised their kicking rhythm at this tempo, i.e. at 80% kicking frequency. In the one-side trial, the swimmers performed UUS with the metronome device (Normal). In the other-side trial, the swimmers performed UUS with tape application aimed at restricting the swimmers ankle joints’ plantar flexions (Tape). The order of the two trials was randomised for all swimmers, who were asked to maximise their swimming velocity for all trials. A previous study used both elastic and non-elastic tapes, obtaining a significant reduction of the ankle’s plantar flexion by approximately 30% (Willems et al., 2014). However, when the same conditions were tested during the preliminary experiment, many swimmers were unwilling to use non-elastic tape because it caused pain; therefore, elastic tape (SEHA50F; Nichiban Co., Ltd, Japan) with stretching and waterproof properties was only used. In addition, it was confirmed that the tape would not detach underwater and once UUS motion was added (Figure 1(b)).
Dynamics of carving runs in alpine skiing. I. The basic centrifugal pendulum
Published in Sports Biomechanics, 2022
Here we critically revise the model of ideal carving and investigate if its assumptions are too restrictive. In particular, we focus our attention on the condition of zero torque. Indeed, this condition implies a quasi-static body position during the turn combined with dynamic transitions between the turns, whereas we often see good skiers effortlessly moving from turn to turn in a smooth continuous and rhythmic fashion. These movements are very reminiscent of a metronome or a inverted pendulum.