Influence of experience of treadmill exercise on visual perception while on a treadmill: Influence of experience on treadmill capture

Influence of experience of treadmill exercise on visualperception while on a treadmill

YOSHIKO YABE* and GENTARO TAGA University of Tokyo

Abstract: A firm linkage exists between a motor command and its expected feed-back. When we are exposed to a conflict between expected and actual feedback in anew context, we form a new linkage between action and perception, which may befurther strengthened by prolonged experience. In this paper, we attempt to identifywhether the linkage between treadmill locomotion and visual processing in relation tooptic flow is strengthened in experienced users of treadmills. Yabe and Taga (2008)showed that ambiguous apparent motions are perceived to be moving downwardmore frequently when the stimuli are shown in front of the observers’ feet on atreadmill when walking compared with when standing. Here, their experimental datawas reanalyzed in relation to the experience of using the treadmill. The result revealedthat habitual treadmill exercise reduced the difference in perceived direction of visualmotion between the walking and standing conditions. It should be noted that thetreadmill users showed perceptual “downward” bias for both the standing andwalking conditions. The results suggest that treadmill users tend to activate thehabitual linkage between treadmill locomotion and perception of optic ground floweven when they are just standing on a treadmill.jpr_425 67..77

Key words: human locomotion, visual context, locomotor aftereffect, treadmill,motor adaptation.

Recently, growing evidence has confirmed thathow people move may affect how they see(Ishimura & Shimojo, 1994; Maruya, Yang, &Blake, 2007; Wexler, Panerai, Lamouret, &Droulez, 2001; Wohlschläger, 2000; Yabe &Taga, 2008). These studies show that motorplanning or execution plays an important rolein resolving conflicts between incompatiblevisual perceptions. For example, using two-alternative forced-choice (2-AFC) tasks, Yabeand Taga (2008) reported “treadmill capture”,in which ambiguous apparent-motion stimuli ofhorizontal gratings placed in front of partici-pants’ feet were perceived to move downwardmore frequently during walking on a treadmillthan during standing on it. There may be a tight

linkage between forward walking and back-ward (i.e. downward in front of the feet) opticflow, which may serve as a constraint to reducethe degree of freedom in spatial vision duringself-motion.A schematic of this model is shownin Figure 1 (left).

Not only how a person moves but also howhe/she had moved can affect visual perception.A linkage between a motor command and itssensory feedback can be learned during sen-sorimotor experience. Studies of letter process-ing have shown that writing experience altersthe perception of apparent motion (Tse &Cavanagh, 2000) and the motor system isactivated during the visual processing ofletters (James & Atwood, 2009). How motor

*Correspondence concerning this article should be sent to: Yoshiko Yabe, Department of Physical and HealthEducation, Graduate School of Education, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.(E-mail: [email protected])

Japanese Psychological Research2010, Volume 52, No. 2, 67–77Special issue: Interaction of perception, cognition, and action

© 2010 Japanese Psychological Association. Published by Blackwell Publishing Ltd.

doi: 10.1111/j.1468-5884.2010.00425.x

experience affects visual processing was inves-tigated using well-controlled experiments in arecent study on motor learning, in whichBrown, Wilson, Goodale, and Gribble (2007)showed that motor learning of a new environ-mental force promotes visual-motion process-ing. In their study, participants were asked tointercept a target moving in the rightward forcefield, after training to make a reaching move-ment in either the null, leftward, or rightwardforce field.The responses of the rightward forcefield group were enhanced, while those of theleftward force field group deteriorated. Byeliminating the opportunity for participants tomove their hand in the force field, the forcedirection had no influence on the stable hand,although the participants recognized andremembered the force adequately. Brown et al.(2007) proposed that once force informationhas been learned and adapted by the motorsystem, the visual system can use the informa-tion to predict the visual motion.

It is well known that brief treadmill runninginduces instant motor aftereffects and the phe-nomenon has been associated with recalibra-

tion of sensorimotor linkages. Anstis (1995)reported that participants who attempted to jogin place on solid ground jogged forward after60 s of treadmill running. The aftereffect wasgreatest for zero delay, that is, immediatelyafter running. When they started jogging inplace after standing still, the forward motiondissipated over the course of 1–2 min. Anstis(1995)’s methods were improved by Durgin,Pelah, Fox, Lewis, Kane, and Walley (2005), whoobserved inadvertent forward motion withoutdeceleration over 20 s with zero delay. Theyalso performed experiments using a treadmillwith an adaptation period of 20 s to 5 min andshowed aftereffects with zero delay. Anstis(1995) also showed that one-legged hopping onthe treadmill did not produce such aftereffectsin the other leg and ruled out the effect of visualadaptation; he concluded that the aftereffectsreveal recalibration to match motor output andfeedback for the backward motion of the tread-mill belt. In contrast, a possible visual adapta-tion during hopping was investigated byDurgin, Fox, and Hoon Kim (2003). Their inter-pretation of Anstis (1995)’s experiments was

Figure 1 Forward locomotion in real life (left) usually produces backward optic flow. The backward flowimplied from prior experience can serve as a constraint to disambiguate the direction of motion in the visualstimuli. We hypothesized that the participants with prolonged treadmill exercise experience (right) shouldadapt to the absence of optic flow during locomotion on a treadmill and thereby should lose the effect of“downward” bias of the perceived direction of motion.

Y. Yabe and G. Taga68

© Japanese Psychological Association 2010.

that there would have been no conflict becausethere was neither flow nor hop on treadmills forthe nonadapted leg. Pelah and Barlow (1996)showed that participants who were instructedto maintain a constant “visual” speed whilerepeatedly walking a 5-m course after 20 min oftreadmill running were seen to accelerate theirpace. It was argued that the running-in-placeaftereffect represents a visuomotor adaptationthat takes place in the absence of normal opticflow (Durgin & Pelah, 1999). In most of theprevious studies, after stepping off the tread-mill, visuomotor expectancies that have beenlinked to motor commands of treadmill loco-motion are thought to be under de-adaptationpressure and recalibrated again while standingor walking on solid ground. The aftereffect ofbrief treadmill running declines over the courseof several minutes. However, few studies havedescribed whether information about themoving surface is stored if the participantrepetitively experiences treadmill running.Pelah and Barlow (1996) mentioned that long-term experience of exercise reduced the after-effect, even though their tasks were only of theorder of minutes.

Here, we examine whether long-term tread-mill exercise causes a user to store the specificlinkage between motion and perception, and tothereby change the magnitude of treadmillcapture (Yabe & Taga, 2008), which is presum-ably based on a tight linkage between normallocomotion on the ground surface and down-ward optic flow. On the basis of the abovemen-tioned studies on treadmill illusions, treadmillrunning or walking constructs a new linkagebetween locomotion on a treadmill and theabsence of optic flow.We therefore hypothesizethat if the information on the motor-perceptuallinkage during each exercise is stored, the par-ticipants who are prolonged treadmill usersshould perceive “downward” visual motionfewer times than inexperienced participants.A schematic of this hypothesis is shown inFigure 1 (right). However, even for the experi-enced participants, the duration of exerciseon treadmills is far shorter than the durationspent on solid ground. It is an open questionwhether the exercise on treadmills can change

the treadmill capture, which may be based onthe daily experience in life.

Methods

We derived data from Experiment 2 of Yabeand Taga (2008) and reanalyzed it in terms ofthe participants’ experience in treadmill exer-cise. In this section, we present an overview ofthe participants, stimuli, and experimentaldesign (for details see Yabe & Taga, 2008). Theexercise history was obtained by conducting anewly developed questionnaire survey.

ParticipantsTwenty-one healthy individuals participatedin the experiment. They were all naïve tothe purpose of the study. Each participanthad normal or corrected-to-normal vision.Informed consent was obtained from all partici-pants. Data from one participant was excludedfrom the analysis due to persistent unidirec-tional judgment during the sessions (in 19 of 22trials). In addition, one female participant didnot provide her history of treadmill exercise,and was thus excluded from the analysis. Weanalyzed data from 7 men and 12 women, 20–33years old (mean age, 24 years) and 150–170 cmin height (mean height, 163 cm).

StimuliThe stimuli were generated on a Windows com-puter and presented on a 15-in. LCD monitor(EIZO FLexScan L355).The refresh rate of thedisplay was 75 Hz, and the resolution was1024 ¥ 768 pixels. As described in Figure 1a ofYabe and Taga (2008), the stimulus display wasa horizontal grating pattern drawn with four-cycle sinusoidal luminance presented within asquare window of side 14.85 cm, mounted on ablack background. The visual angle and lumi-nance varied depending on the stationary posi-tions on the treadmill and the height of theparticipants. The visual angle was approxi-mately 5.9–7.0 deg. The maximum value of theluminance was approximately 20–25 cd/m2 andthe minimum was approximately 1.8–1.9 cd/m2;the luminance contrast was between 84% and

Influence of experience on treadmill capture 69


92%. The stimulus image was repainted tentimes per second. At the time of repainting, thegrating was shifted by a constant distance. Themagnitude of the shift affected the perceiveddirection of the gratings. When the shift wasequal to half the width of one cycle of the grat-ings (1.86 cm; approximately 0.8 deg when thevisual angle of the stimulus window was themean, 6.4 deg), the spatial phase differencebecame 180 deg. Thus, a counterphase grating(i.e. a truly directionally ambiguous grating)was presented with the temporal frequency of5 Hz (Figure 1b, middle, Yabe & Taga, 2008). Ifthe perceived direction of motion was unidirec-tional, its apparent speed was approximately8.0 deg/s. With decreasing spatial phase differ-ence from 180 deg, the apparent motion direc-tion was biased upward (Figure 1b, top, Yabe &Taga, 2008). In contrast, with increasing spatialphase difference, the direction was biaseddownward (Figure 1b, bottom, Yabe & Taga,2008). In either case, the velocity of the appar-ent motion slows down as the spatial phase dif-ference recedes from 180 deg and approaches0 deg or 360 deg. The minimum absolute speedwas 6.0 deg/s, which was implemented by theshift of 135 deg or 225 deg, given that anelement of the gratings in a frame is regardedas fused with the closest one in the next(Figure 1b, Yabe & Taga, 2008). We presentedno fixation point on the stimulus in order to notgive a reference point for judging the motiondirection.

Experimental designParticipants were either standing or walking ona treadmill (Nihon Kohden Aeromill STM-1420; Figure 1a, Yabe & Taga, 2008). The tread-mill speed was set at 91.66 cm/s. Under thewalking condition, participants were told to usethe handrails only if absolutely necessary forsafety purposes. No participants actually usedthe handrails during the experiment. Apparentmotion stimuli of a horizontal sine wave gratingwith shifts of the phase were displayed on a15-in. LCD monitor in front of the participants’feet. In each trial, the shift of the sine wavegrating was randomly chosen from 11 varia-

tions between 135 deg and 225 deg, with acounterphase grating that shifts 180 deg, fiveupward ones that shift less than 180 deg, andfive downward ones that shift more than180 deg. We darkened the room to make theparticipants’ feet and the texture of the tread-mill belt as invisible as possible. The belt wascolored solid dark green and its luminance was0.005 cd/m2 at most. It had an indented pat-terned surface with furrows 0.6 cm apart, whichcorresponds to approximately 0.2 deg for a 160-cm-tall participant. It is unlikely that partici-pants could see the belt motion with peripheralviewing (Anderson, Mullen, & Hess, 1991).Each participant determined the position onthe treadmill at which they would stand or walkthroughout the experiment so that they couldwatch the display clearly. Participants were toldthat they would be shown displays of a movinghorizontal grating, and that “the gratings moveupward or downward.” Participants were alsotold to view the entire stimuli and not to fixateon their fringes. In each trial, the grating patternwas presented for 3 s, followed by a 10-s pre-sentation of a central white cross on a blackbackground as a fixation target for gazing. Assoon as the display switched from the stimulusto the screen of the fixation cross, the partici-pants fixated on the cross continuously andmade a forced-choice judgment about whetherthe motion direction of the gratings presentedjust prior moved downward or upward. Allresponses were given orally and entered into acomputer by an experimenter without anyfeedback. Each observer took part in one prac-tice session and five experimental sessions. Oneexperimental session consisted of a standingcondition block and a walking condition block,which were performed in a counterbalancedABBA order. Each block consisted of 22 trialsand represented 11 distinct displays showntwice in random order. The stimuli were sine-wave gratings whose phase shift was randomlychosen from 11 varieties with a counter-phasegrating, and five upward and five downwardones between 122.4 deg and 237.6 deg.The totalamount of time required for all sessions wasapproximately 90 min. The participants stoodon a board bridged over the running treadmill



during the standing condition and the treadmillwas kept at 91.66 cm/s, that is, at the same speedas during the walking condition.

Prior to the start of the experimental tasks,the participants answered a question assessingwhether or not they had any experience intreadmill exercise. The participants were cat-egorized as non-treadmill runner (nTR) if theyhad experienced treadmill walking three timesor less. This limit was chosen to include theparticipants who have happened to use a tread-mill but have not used one for exercise habitu-ally. Participants experienced in habitualtreadmill exercise were categorized as treadmillrunner (TR). The two groups of nTR and TRdiffer in their exercise history; the minimumnumber of exercise sessions experienced by theTR participants is 16 times (see Table 2).

Detailed history of treadmill exerciseWe conducted a questionnaire survey via email(Appendix) only among TR participants tocollect details on their experience of treadmillexercise.

Results

The demographics of the study population aregiven in Table 1. There were no differencesbetween the TR and nTR groups in terms ofage (two tailed t-test, p = .79), height (two tailedt-test, p = .34), sex (c2 = 0.003, 1; p = .96), andvision (c2 = 2.77, 1; p = .1).

Comparison between nTR and TRWe examined the probability of trials in whichthe grating appeared to move “downward”(averaged for all participants) as a function of

the physical shift of the grating. Figure 2a,bshows the group-averaged probability functionsunder the walking and standing conditions.

When the physical shift was 180 deg (coun-terphase gratings), the downward probabilitywas .59 (SD = 0.21) under the walking condi-tion and .35 (SD = 0.18) under the standingcondition for nTR. The difference between thewalking and standing conditions for nTR wassignificant, two-tailed paired t-test, t(10) = 3.49,p < .01. The downward probability was .65(SD = 0.19) under the walking condition and.54 (SD = 0.24) under the standing conditionfor TR. We found no significant differencebetween the walking and standing conditionsfor TR, t(7) = 1.84, p = .1.

The probability of the “downward”responses was calculated and fitted with a logis-tic function for each participant. From the fittedfunctions, the point of subjective equality (PSE,i.e. the probability of the “downward”responses equal to .5) was estimated for eachparticipant (Figure 2c,d). A statistical analysisof nTR showed that the PSE, (176.3°,SD = 9.23) under the walking condition was sig-nificantly different from that (183.0 deg,SD = 7.15) under the standing condition, two-tailed paired t-test, t(10) = 3.31, p < .01. For TR,the PSE (176.53 deg, SD = 4.68) under thewalking condition was not significantly differ-ent from that (178.12 deg, SD = 6.73) under thestanding condition, two-tailed paired t-test,t(7) = 0.73, p = .49.

Correlation between amount of treadmillcapture and history of using the treadmillThe responses to the questionnaire by the TRparticipants are summarized in Table 2. Wecould not contact a male TR participant, who

Table 1 Details of participants

Characteristics Non-treadmill runners Treadmill runners

N 11 8Age (mean � SD; range), years 24.3 � 3.80 (20–33) 23.9 � 1.96 (22–28)Sex (number of women) 7 5Height (mean � SD; range), cm 162.3 � 7.48 (150–170) 165.13 � 4.09 (158–170)Vision (number of unaided participants) 7 2



was excluded from further analysis. The totalnumber of exercise was obtained by multi-plying the exercise period and frequency foreach TR participant. By multiplying thetotal number of exercise sessions and therunning time, the total duration of exercise wasestimated.

We plotted the PSE difference between thewalking and standing conditions against thetotal number of exercise sessions and the totalduration of exercise for each TR participant(Figure 3a,b). There is a negative correlationbetween the total number of exercise sessionsand the PSE difference, although it is not sig-

Figure 2 The graphs on the left show the probability of the “downward” responses as a function of the shiftof the sine wave by mean and SE, averaged across participants who were either (a) non-treadmill runners(nTR) or (b) treadmill runners (TR). The distance of the shift of the sine wave is the physical bias of the stimulusdisplay represented in spatial phase difference. The displacement at 180 deg makes a counterphase grating.( ) The probability under the walking condition. ( ) The probability under the standing condition. Thegraphs at the right show the point of subjective equality (PSE) under the standing condition and that under thewalking condition for (c) nTR and (d) TR participants.



nificant, r = -0.71, p = .07. There was no signifi-cant correlation between the total duration ofexercise and the PSE difference, p = 0.462. ThePSE of the walking condition (Figure 3c,d) didnot show a significant correlation with eitherparameter. The PSE of the standing conditionshowed a negative correlation with the totalnumber of exercise sessions, r = -0.85, p < .05,and with the total duration of exercise,r = -0.84, p < .05, as shown in Figure 3e,f.

There was no significant effect of the lengthof the break from treadmill exercise (i.e. howmany months had passed since the last exer-cise) on the PSE difference (p = .86) betweenthe two conditions, the PSE of the standing con-dition (p = .261), and the PSE of the walkingcondition (p = .146), as shown in Figure 4.

Discussion

In this study, we have hypothesized thathabitual treadmill exercise modulates thelinkage between motion and perception,resulting in influences on the perceived direc-tion of ambiguous motion during walking orstanding on a treadmill (treadmill capture).We obtained details of treadmill exercisehistory from participants to examine the effectof the amount of exercise on treadmillcapture. The analysis indicated that thoseparticipants without experience of treadmillexercise perceived directionally ambiguous

motions of shifting frames of sinusoidal hori-zontal gratings in front of their feet as movingdownward more frequently while walking thanwhile standing on a treadmill. In contrast, theparticipants who were experienced in tread-mill exercise did not show the effect that thegratings are perceived downward more fre-quently. Although this supports the hypothesisthat visual perception on a treadmill isaffected by the prolonged experience of loco-motion on treadmills, it does not support ourhypothesis that long-term experience of exer-cise on treadmills reduces the perceptualdownward bias of flow of motion under thewalking condition. The data indicates that theexperience of treadmill exercise did not affectthe response while walking, but affected itwhile standing on a treadmill.

It should be noted that there are considerabledifferences between the instant adaptation oftreadmill locomotion in the previous studies andthe effect of repetitive experience on treadmillcapture in the present study. In the case ofinstant aftereffects of treadmill locomotion,par-ticipants inadvertently walked forward (Anstis,1995) or accelerated (Pelah & Barlow, 1996) onsolid ground soon after stepping off the tread-mill,as if the ground surface,rather than only thetreadmill belt, were moving. The motor adapta-tion to the motion of treadmill belt leads to arecalibration of motor command; that is, as theparticipant starts walking, the ground surfaceappears to go backward in any context. In the

Table 2 Reported experience of treadmill exercise

Participantno.

Exerciseperiod (months)

Frequency(per month)

Runningtime (h)

Break(months)

Total no. ofexercise sessions

Totalduration (h)

02 2 8 0.5 36 16 803 12 4 2 0 48 9604 18 0.75 0.75 6 13.5 10.1305 24 8 0.33 0 192 63.3610 18 12 2.25 20 216 48613 2 12 0.33 78 24 7.9217 3 12 1 12 36 36

Note. Exercise period, Frequency, Running time, and Break were obtained from Questions 1, 2, 3, and 4 ofAppendix I, respectively. The total number of exercise sessions times was obtained by multiplying Exerciseperiod with Frequency. The total duration was estimated by multiplying the Total number of exercise sessionsand Running time.



Figure 3 Scattergram to visualize intersubject correlation between the point of subjective equality (PSE)statistics and the statistics of exercise history. Data from seven participants from the treadmill runners groupare plotted, with one point corresponding to one subject. (a–b) Intersubject scattergram between the PSEdifference and (a) total number of exercise sessions and (b) total duration of exercise. The solid line indicateslinear regression: y = -0.04x + 3.303. (c–d) Intersubject scattergram between the PSE under the walkingcondition and (c) total number of exercise sessions and (d) total duration of exercise. (e–f) Intersubjectscattergram between the PSE under the standing condition and (e) total number of exercise sessions and (f)total duration of exercise. The solid lines indicate linear regression: (e) y = -0.045x + 179.796 and (f)y = -0.022x + 178.550.



case of long-term treadmill exercise, users arerepeatedly exposed to the process of adaptationand washout. This may produce a context-specific recalibration, which indicates that thereappears to be no optic flow while walking on atreadmill. The context-specific recalibrationis likely not to be diminished for years afterthey quit the exercise.Thus, long and short adap-tation may induce different degrees of context-specificity of recalibration.

Context-specificity has been examined inseveral previous studies of locomotor afteref-fects. Pelah and Barlow (1996) mentioned thatthe aftereffect of treadmill running was mostcompelling when walking on the treadmill itselfafter it has stopped. More recently, the strikingphenomenon in which we experience an oddsensation on a broken escalator was investi-gated (Bunday, Reynolds, Kaski, Rao, Salman,& Bronstein, 2006; Fukui, Kimura, Kadota,Shimojo, & Gomi, 2009; Reynolds & Bronstein,2003). Bunday et al. (2006), using a linearmotor-powered sled in their laboratory, showedthat fast locomotor aftereffects can be gener-ated after participants walked on a movingsled only one or two times. Reynolds and Bron-stein (2007) suggested that their “laboratoryaftereffect” may differ from the broken escala-tor effect with respect to the time course. Theremay be a very strong association between the

perceptual cues linked to the movement of realescalators, which are reinforced on a daily basis.Fukui et al. (2009) used a real escalator toinvestigate the occurrence of the odd sensationqualitatively. Comparing the kinematic proper-ties during stepping onto a stopped escalatorwith those while stepping onto a moving oneand onto wooden stairs, they found that pos-tural forward sway, rather than inadequate legmovement, is essential for the perception of theodd sensation. They indicated that the odd sen-sation represents two different components ofmotor control: a voluntary component and anautomatic control.When we step onto a brokenescalator, our legs are controlled rather volun-tary while our posture is largely controlled inan automatic fashion. Postural sway representsthe automatically triggered habitual motorprogram specific to the context of an escalator.

The present study revealed that the history oftreadmill exercise affects the responses underthe walking and standing conditions differently,which can be explained by separate mecha-nisms that may work under each condition(Figure 5). While people spend most of theirlives on solid ground, treadmill runners experi-ence a different context. Our findings showedthat treadmill exercise did not affect the visualresponse under the walking condition. Thisindicates that the lifetime experience of

Figure 4 Scattergram to visualize intersubject correlation between the point of subjective equality (PSE)statistics and break of exercise. Data from seven participants are plotted; one point corresponds to onesubject. Intersubject scattergram (a) between the PSE difference and break, (b) between the PSE under thestanding condition and break, and (c) between the PSE under the walking condition and break.



locomotion on solid ground can keep produc-ing the preexisting effect that treadmill walkingfacilitates unidirectional perception of thecounterphase gratings in front of the observers’feet in both non-treadmill runners and tread-mill runners. The important finding of thepresent study is that the effect of experience oftreadmill exercise was prominent under thestanding condition. The reason why such aneffect was only observed for the participantswho have experienced prolonged exercise ontreadmills can be related to the fact that theyprobably acquired the linkage between theirlocomotion and visual perception of the back-ward flow of the moving belt of a treadmill andthat standing still on a treadmill provides anovel and “odd” context for them, just likewalking on a broken escalator.

References

Anderson, S. J., Mullen, K. T., & Hess, R. F. (1991).Human peripheral spatial resolution for

achromatic and chromatic stimuli: Limitsimposed by optical and retinal factors. Journal ofPhysiology, 442, 47–64.

Anstis, S. (1995). Aftereffects from jogging. Experi-mental Brain Research, 103, 476–478.

Brown, L. E., Wilson, E. T., Goodale, M. A., &Gribble, P. L. (2007). Motor force field learninginfluences visual processing of target motion.Journal of Neuroscience, 27, 9975–9983.

Bunday, K., Reynolds, R., Kaski, D., Rao, M., Salman,S., & Bronstein, A. (2006). The effect of trialnumber on the emergence of the ‘broken escala-tor’ locomotor aftereffect. Experimental BrainResearch, 174, 270–278.

Durgin, F. H., Fox, L. F., & Hoon Kim, D. (2003). Notletting the left leg know what the right leg isdoing: Limb-specific locomotor adaptation tosensory-cue conflict. Psychological Science, 14,567–572.

Durgin, F. H., & Pelah, A. (1999). Visuomotor adap-tation without vision? Experimental BrainResearch, 127, 12–18.

Durgin,F.H.,Pelah,A.,Fox,L.F.,Lewis,J.,Kane,R.,&Walley, K. A. (2005). Self-motion perceptionduring locomotor recalibration: More than meetsthe eye. Journal of Experimental Psychology:Human Perception and Performance,31, 398–419.

Figure 5 Schematic explanation of the results. Even if the participant has many years of treadmill exerciseexperience, the duration of exercise on treadmills (black arrow drawn in the arrow of “Real Life”) cover onlypart of the life spent on solid ground. Under the walking condition, the backward flow experienced daily duringlocomotion can contribute to disambiguating the direction of movements in the visual stimuli for both treadmillrunners (TRs) and non-treadmill runners. Under the standing condition, the perceptual “downward” bias wasobserved only for TRs, which indicates the influence of context-specific adaptation to the locomotion on amoving surface.



Fukui, T., Kimura, T., Kadota, K., Shimojo, S., &Gomi, H. (2009). Odd sensation induced bymoving-phantom which triggers subconsciousmotor program. PLoS One, 4, e5782.

Ishimura, G., & Shimojo, S. (1994). Voluntary actioncaptures visual motion. Investigative Ophthal-mology and Visual Sciences, 35 (Suppl.), 1275.

James, K. H., & Atwood, T. P. (2009). The role ofsensorimotor learning in the perception of letter-like forms: Tracking the causes of neural special-ization for letters. Cognitive Neuropsychology,26, 91–110.

Maruya, K., Yang, E., & Blake, R. (2007). Voluntaryaction influences visual competition. Psychologi-cal Science, 18, 1090–1098.

Pelah, A., & Barlow, H. B. (1996). Visual illusion fromrunning. Nature, 381, 283.

Reynolds, R. F., & Bronstein, A. M. (2003). Thebroken escalator phenomenon: Aftereffect ofwalking onto a moving platform. ExperimentalBrain Research, 151, 301–308.

Reynolds, R. F., & Bronstein, A. M. (2007). Themoving platform after-effect reveals dissociationbetween what we know and how we walk.Journal of Neural Transmission, 114, 1297–1303.

Tse, P. U., & Cavanagh, P. (2000). Chinese and Ameri-cans see opposite apparent motions in a Chinesecharacter. Cognition, 74, B27–B32.

Wexler, M., Panerai, F., Lamouret, I., & Droulez, J.(2001). Self-motion and the perception of sta-tionary objects. Nature, 409, 85–88.

Wohlschläger, A. (2000). Visual motion primingby invisible actions. Vision Research, 40, 925–930.

Yabe, Y., & Taga, G. (2008). Treadmill locomo-tion captures visual perception of apparentmotion. Experimental Brain Research, 191, 487–494.

(Received October 2, 2009; accepted November 14,2009)

AppendixQuestionnaire1 For how long have you or had you been exercising with a treadmill (in months)?2 How frequently do you exercise in a month?3 What is the typical duration of an exercise session?4 Was the experiment conducted during the abovementioned exercise period? If you had already

stopped exercising, how long was the break until the experiment was conducted? That is, howmany months have passed since the last exercise?



Influence of experience of treadmill exercise on visual perception while on a treadmill: Influence of experience on treadmill capture

Documents