| Paper Abstract and Keywords |
| Presentation |
2006-03-17 15:45
Active adjustment of joint stiffness in ball hitting
Akihiro Kashiwade, Fumihiko Ishida, Hiroyuki Shimai, Katsumi Wada, Yutaka Sakaguchi (UEC) |
| Abstract |
(in Japanese) |
(See Japanese page) |
| (in English) |
The present study asks how humans adjust joint sti®ness according to task conditions. To answer this question, we ¯rst ran a behavioral experiment where subjects hit a ball by the palm as strongly as possible. We measured EMG activities of elbow and wrist muscles together with arm trajectory, and examined how they varied according to the mass of the ball. The magnitude of co-activation of the wrist muscles increased with the ball mass.
Next, we performed a numerical experiment simulating the behavioral experiment to see the e®ect of joint sti®ness on the task performance. Two extreme models of the wrist joint were prepared: In \motor model", joint torque was generated purely by motor command. In \spring model", no active torque was generated but the joint was elastic property. We observed the initial ball velocity in various mass conditions, with examining the e®ect of variance of motor command. The motor model consistently marked superior performance if the motor command was issued at the best timing while the spring model was more robust against the variance of motor command. This robustness was more prominent for a heavier ball, meaning that greater joint sti®ness may stabilize the task performance. These results together show the possibility that humans actively adjust the joint sti®ness in order to mark better motor performance against unpredictable variance of motor command. |
| Keyword |
(in Japanese) |
(See Japanese page) |
| (in English) |
co-contraction / joint stiffness / task performance / temporal variance of motor command / / / / |
| Reference Info. |
IEICE Tech. Rep., vol. 105, no. 659, NC2005-162, pp. 67-72, March 2006. |
| Paper # |
NC2005-162 |
| Date of Issue |
2006-03-10 (NC) |
| ISSN |
Print edition: ISSN 0913-5685 |
| Download PDF |
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| Conference Information |
| Committee |
NC |
| Conference Date |
2006-03-15 - 2006-03-17 |
| Place (in Japanese) |
(See Japanese page) |
| Place (in English) |
Tamagawa University |
| Topics (in Japanese) |
(See Japanese page) |
| Topics (in English) |
General |
| Paper Information |
| Registration To |
NC |
| Conference Code |
2006-03-NC |
| Language |
Japanese |
| Title (in Japanese) |
(See Japanese page) |
| Sub Title (in Japanese) |
(See Japanese page) |
| Title (in English) |
Active adjustment of joint stiffness in ball hitting |
| Sub Title (in English) |
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| Keyword(1) |
co-contraction |
| Keyword(2) |
joint stiffness |
| Keyword(3) |
task performance |
| Keyword(4) |
temporal variance of motor command |
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| 1st Author's Name |
Akihiro Kashiwade |
| 1st Author's Affiliation |
The University of Electro-Communications (UEC) |
| 2nd Author's Name |
Fumihiko Ishida |
| 2nd Author's Affiliation |
The University of Electro-Communications (UEC) |
| 3rd Author's Name |
Hiroyuki Shimai |
| 3rd Author's Affiliation |
The University of Electro-Communications (UEC) |
| 4th Author's Name |
Katsumi Wada |
| 4th Author's Affiliation |
The University of Electro-Communications (UEC) |
| 5th Author's Name |
Yutaka Sakaguchi |
| 5th Author's Affiliation |
The University of Electro-Communications (UEC) |
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| Speaker |
Author-1 |
| Date Time |
2006-03-17 15:45:00 |
| Presentation Time |
25 minutes |
| Registration for |
NC |
| Paper # |
NC2005-162 |
| Volume (vol) |
vol.105 |
| Number (no) |
no.659 |
| Page |
pp.67-72 |
| #Pages |
6 |
| Date of Issue |
2006-03-10 (NC) |
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