( F o r mN o .3 ) Name:XIONGJINGHONG( 熊境鴻 ) D i s s e r t a t i o nt i t l e :ThumbPerformanceandMovementCoverageonSmartphone Touchscreens (スマートフォンのタッチスクリーンに対する親指のパフオマンスと動作域) Category:A ( 打 A b s t r a c to fD i s s e r t a t i o n T h i ss t u d yaimedt oi n v e s t i g a t et h er e l a t i o n s h i p sbetweenthumbm u s c l ea c t i v i t ya n dt o u c h thumbmovingo r i e n t a t i o n sa n dc i r c l i n gd i r e c t i o n sonas m a r t p h o n et o u c h s c r e e n， a s b u t t o ns i z e， w e l la st h er e l a t i o n s h i p sbetweenthumbc o v e r i n ga r e aa n dp o s i t i o nons m a r t p h o n et o u c h s c r e e n s ando t h e rr e l e v a n tf a c t o r st h a tc o u l da f f e c tt h ethumbp e r f o r m a n c e . ，f a t i g u et i m e，t a p p i n gs p e e da n dp e r c e i v e d Throught h emeasurementso fe l e c t r o m y o g r a p h y namely ，a d d u c t o rp o l l i c i s( A P )， f l e x o rp o l l i c i sb r e v i s( F P B )， e x e r t i o ni nt h es i xthumbm u s c l e s， a b d u c t o rp o l l i c i sb r e v i s(APB)，a b d u c t o rp o l l i c i sl o n g u s(APL)，f i r s td o r s a li n t e r o s s e o u s( F D I )， a n de x t e n s o rd i g i t o r u m(ED)， i twasf o u n dt h a ts m a l ls i z et o u c hb u t t o na n df l e x i o n e x t e n s i o no f thumbmovingo r i e n t a t i o nt e n dt oa f f e c tt h ethumbp e r f o r m a n c eons m a r t p h o n et o u c h s c r e e n s . Ther e a s o n swerec o n s i d e r e da ss m a l ls i z et q u c hb u t t o n sa r el i k e l yt oi n c r e a s et h ee f f o r t r e l a t e d andf l e x i o n e x t e n s i o no fthumbmovingo r i e n t a t i o ni n c r e a s e st h a tonAPL .As demandsonFDI， ar e s u l t， t h ethumbbecomesl e s ss u s c e p t i b l et of a t i g u e， andt h ethumbp e r f o r m a n c ei sr e d u c e d . h i sr e s e a r c ha l s of o u n dt h a twhent h ethumbmovesi na na d d u c t i o n a b d u c t i o n F u r t h e r m o r e，t h ethumb c o v e r i n ga r e aandp o s i t i o nt e n dt ob e o r i e n t a t i o nons m a r t p h o n et o u c h s c r e e n s，t a f f e c t e dbyt h eu s e ra g e， thumbl e n g t ha n dt o u c h s c r e e ns i z e .T h a ti s， e l d e r l yl e a v e smores p a c e l . m r e a c h a b l ea tt h er i g h ts i d eo ft h et o u c h s c r e e nt h a nt h eyoungo n e s， a n dl o n g e rthumbsa r ea b l e t or e a c hl a r g e ra r e aw h e r e a sl e a v emoreu n r e a c h a b l es p a c ea tt h er i g h ts i d ea n db o t t o mo ft h e t h i ss t u d ya l s of o u n dt h a ti n c r e a s i n g t o u c h s c r e e ncomparedw i t ht h es h o r t e rt h u m b s .I na d d i t i o n， t h et o u c h s c r e e ns i z ed o e sn o tn e c e s s a r i l yi n c r e a s et h ethumbc o v e r i n ga r e ai nasamer a t i o . T a k ea l li n t oa c c o u n t， t h e s es t u d i e sdrawo u tt h r e e .s u g g e s t i o n sf o rt h ed e s i g n so fu s e ri n t e r f a c e t h es m a l lt o u c hb u t t o n ss h o u l db em i n i m i s e di no r d e rt o i nh a n dh e l dt o u c h s c r e e n s .F i r s tofa l l， r e d u c et h ee f f o r t r e l a t e ddemandsonFDI， whichc o u l dc a u s et h ethumbt ob el e s ss u s c e p t i b l et o f a t i g u e .S e c o n d l y ， n o to n l ys m a l lt o u c hb u t t o n sb u ta l s of l e x i o n e x t e n s i o nmovementss h o u l db e m i n i m i s e d，i no r d e rt or e d u c et h ee f f o r t r e l a t e ddemandsonFDIa n dAPL，e s p e c i a l l yf o ra g e d u s e r s .T h i r d l y ， t h ed e s i g nofh a n d h e l dt o u c h s c r e e ni n t e r f a c es h a l lc o m p r e h e n s i v e l yc o n s i d e rt h e e n g t hands c r e e ns i z e . o v e r a l le f f e c t so fa g e，thumbl