S116 Abstracts / Gait & Posture 39S (2014) S1–S141

Fig. 1. The first panel (A) shows mean arm swing amplitude of the subjects (left and right combined) at the three different walking speeds for both simulations: the ACT(dark grey) and PAS (light grey) data (average ± SD). The second panel (B) is displaying the mean relative phase of the arm swing for the ACT (dark grey) and PAS (light grey)data (average ± SD).

Reference

[1] Meyns P, Bruijn SM, Duysens J. The how and why of arm swing during humanwalking. Gait Posture 2013 [Epub ahead of print].

[2] Jackson KM, Joseph J, Wyard SJ. A mathematical model of arm swing duringhuman locomotion. J Biomech 1978;11:277–89.

http://dx.doi.org/10.1016/j.gaitpost.2014.04.159

P47

Kinematic development of infants and theirinteraction with their mothers during specifictasks

K.T. Kaliarntas 1,∗, K. Ishijima 2, K. Momose 2, A.J.Murphy 1, N. Kawahara 3, K. Negayama 2, J.Delafield-Butt 4

1 Biomedical Engineering, University of Strathclyde,Glasgow, United Kingdom2 Waseda Universty, Tokyo, Japan3 Kyoritsu Women’s University, Tokyo, Japan4 Department of Education, University of Strathclyde,Glasgow, United Kingdom

Introduction and aim: Everyday social projects exhibit regularaction patterns structured by their motor goals. Shared under-standing is developed in infancy in participation in common motorprojects by learning anticipations of their motor intention, suchas during feeding, being picked up or put down, and in play [1].Co-operative, participatory games and rituals enacted every dayby mothers and babies likely establish distinct, culturally specificmotor styles. Generation of non-verbal embodied understanding isdependent on intent participation, and requires co-ordination andcontingent timing of actions from both mother and baby [2]. Howinfants develop social anticipations and co-ordinated movementto interact with others is a fundamental question for cognitive sci-ences, and for our understanding the embodied basis of culturallearning.

In this study, we examine the action patterns of mothers andtheir babies from Japan and Scotland during every day games andrituals. Goal-directed movements within these are analysed fortheir prospective control of action using General Tau Theory, amathematicopyschophysical theory of prospective perceptual con-trol of movement shown to be universally basic in animal motorcontrol [3,4]. The aim of this study is three-fold: (a) to computa-

tionally determine perceptuomotor control variables employed inmother–infant interactions and the action patterns exhibited at dif-ferent stages of development; (b) to determine cultural differencesin motor style between Japanese and Scottish mother–infant pairs;and (c) to develop an automated kinematic model for reliable dataanalysis of mother–infant interaction.

Patients/materials and methods: This study examinedaction patterns of 10 mother–infant pairs from Japan and 10mother–infant pairs from Scotland at six and nine months ofage. Motion capture was performed with comparable 3D motionanalysis systems recording at 100 Hz: a 12-camera Vicon Nexus(Oxford, UK) system deployed at the University of Strathclyde inScotland, and an 8-camera Optitrack system (NaturalPoint Inc.,USA) deployed at Waseda University in Japan. Kinematic modellingwas performed on the Scottish data with a Vicon Upper Body PIGmodel for mothers and a custom-made model developed for infantkinematic analysis. All pairs performed three different tasks: (i)feeding with a spoon, (ii) picking up and putting down the baby,and (iii) ticking in free play. Trajectory data of action effectors,namely the mother’s hands, were analysed for goal-directed kine-matics and tau perceptuomotor control variables. Japanese andScottish movement data are compared. The study was approvedby the School of Education Ethics Committee at the University ofStrathclyde.

Results: This project presents three sets of results. (1) Tau anal-yses of goal-directed action patterns in the feeding, picking up, andputting down the baby. (2) Comparative analysis of Japanese andScottish mother’s actions patterns. (3) Development of automatedkinematic model for infant motion analysis.

Discussion and conclusions: This projects advances under-standing of the embodied cultural learning. It is the first study to use3D motion analysis to study culturally specific kinematic interac-tion patterns in child development. The study provides new insightsin the area of embodied social cognition and their cultural specifici-ties. Furthermore, to achieve these goals, we have made progressin development of a new full-body infant motion capture markerset and kinematic model.

Reference

[1] Delafield-Butt JT, Trevarthen C. A theory of the development of human commu-nication. In: Cobley P, Schultz P, editors. Handbook of Communication Science.Berlin: Gruyter Mouton; 2013.

[2] Trevarthen C, Delafield-Butt JT. Biology of shared meaning and language devel-opment: regulating the life of narratives. In: Legerstee M, Haley D, Bornstein M,

Abstracts / Gait & Posture 39S (2014) S1–S141 S117

Table 1Mean values of two repetiotions for LOS and LRT in all tested subjects and Pearson’s correlation among values.

Limb Test Subject

1 2 3 4 5 6 7 Pearson’s correlation

Amputated LOS 80.0 79.0 71.5 89.5 64.5 78.0 84.0 0.08 0.36LRT 10.2 10.5 14.6 19.1 11.9 12.9 13.7

Non-amputated

LOS 87.0 88.0 75.0 95.5 72.5 83.0 85.5 0.48LRT 13.9 11.5 17.1 21.4 17.6 11.5 15.8

editors. The developing infant mind: integrating biology and experience. NewYork: Guildford Press; 2013.

[3] Delafield-Butt JT, Pepping G-J, McCaig CD, Lee DN. Prospective guid-ance in a free-swimming cell. Biological Cybernetics 2012;106:283–93,http://dx.doi.org/10.1007/s00422-012-0495-5.

[4] Lee, David N. General tau theory: evolution to date. Perception 2009;38:837–58.

http://dx.doi.org/10.1016/j.gaitpost.2014.04.160

P48

Impact of walking speed and slope of theground on axial force of poles in Nordic walking

Martin Psurny ∗, Miroslav Janura, Jakub Krejcí,Ales Jakubec

Faculty of Physical Culture, Palacky University,Olomouc, Czech Republic

Introduction and aim: Nordic walking, due to its attractivenessand ease of equipment, is becoming more popular and utilised inthe areas of sports, recreation and physiotherapy [1]. Some of itsimpacts on load to the body have not yet been sufficiently explored.The aim of the study was to determine the impact of walking speedand slope of the ground on the magnitude of axial forces, trans-ferred to the poles by upper extremities during Nordic walking.

Materials and methods: The study was participated in by 17healthy subjects, aged 25.9 ± 3.6 years, who went through 12 inde-pendent measurements on a treadmill in various speeds (6.0; 6.6;7.2 and 7.8 km h−1) and slopes (0; 5 and 7.5%). These measurementsprovided us with values of basic spatiotemporal variables, charac-terizing Nordic walking performance and force variables, acting onthe poles.

Results: Increased walking speed led to increase in cycle fre-quency (p < 0.001) and increase in peak poling force and averagepoling force (p < 0.001). Poling time reduced with increasing speed(p < 0.001). Increase in slope of ground had no significant impact onthe magnitude of spatiotemporal and force variables.

Discussion and conclusions: Increased speed of movementduring Nordic walking increases the force, generated by the upperextremities on the poles.

Reference

[1] Morgulec-Adamowicz N, Marszałek J, Jagustyn P. Nordic walking – a new formof adapted physical activity (a literature review). Hum Mov 2011;12(2):124–32.

http://dx.doi.org/10.1016/j.gaitpost.2014.04.161

P49

Lateral reach test and limits of stability inmedial-lateral direction in transtibial amputees

Zuzana Kováciková ∗, Barbora Kolárová, ZdenekSvoboda, Miroslav Janura, Karolína Orechovská

Faculty of Physical Culture, Palacky University,Czech Republic

Introduction and aim: Lateral reach test (LRT) and limits ofstability (LOS) reflects subjects ability to voluntarily control themovement of center of gravity in a given direction without chang-ing the base of support, which is necessary for walking and otherfunctional activities within daily life [1]. The aim of our study wasto evaluate transtibial amputees (TTAs) ability to voluntarily shifttheir center of gravity to the side of amputated and non-amputatedlimb.

Materials and methods: The study group consisted of sevenunilateral traumatic TTAs (2 women, 5 men; mean age 43 ± 11 y,height 1.78 ± 0.12 m, time since amputation 7 ± 6 y).

TTAs performed clinical balance test LRT and test LOS usingdynamic computer posturography (NeuroCom).

LRT measures reaching ability to the side in bilateral stance, thevalues were expressed as a ratio of distance reached by hand of thesubject to body height. LOS reflects the voluntary control of maxi-mal body leaning based on visual feedback, which was expressed asa precentage of theoretical 100% limits of stability [2]. Each test wasperformed with two repetitions. The order of tested directions wasrandomized. Pearson’s correlation was done to see the associationamong LOS and LRT on the side of amputated and non-amputatedleg.

Results: Table 1.Discussion and conclusions: In TTAs, there is a presence of

decreased postural stability as a result of altered sensorimotorintegration and properties of prosthethic components. One aspectwhich mirrors less effective postural control in TTAs is increaseddemand on the intact limb compared to amputated limb withinquiet stance and walking [3,4].

To follow our pilot results TTAs had decreased ability tovoluntarily incline to the side of amputated limb compared to non-amputated in all tested subjects within LOS and in 6 tested subjectsin LRT, there was positive correlation among both tests for ampu-tated limb. Despite different postural strategies which are used toperform reaching task and leaning task [5], it seems that voluntaryposture control on the amputated side in TTAs might be overalllimited.

Reference

[1] Horak FB. Postural orientation and equilibrium: what do we need to know aboutneural control of balance to prevent falls? Age Ageing 2006;35(Suppl. 2):ii7–11.

[2] NeuroCom International: Smart Eqiutest® system operator’ manual (version 8).Clackamus, OR: NeuroCom; 1998.

[3] Isakov E, Keren O, Benjuya N. Trans-tibial amputee gait: time-distance parame-ters and EMG activity. Prosthet Orthot Int 2000;24(3):216–20.

[4] Isakov E, Mizrahi J, Ring H, Susak Z, Hakim N. Standing sway and weight-bearingdistribution in people with below-knee amputation. Arch Phys Med Rehabil1992;73(2):174–8.