Light touch and center of mass stability during treadmill locomotion.

PURPOSE To study the contributions of light fingertip touch on an earth-referenced object to body stability during treadmill locomotion. METHOD Twenty young healthy adults were tested in two blocks of five testing conditions while walking on the treadmill at 3 km/h. In each condition, subjects were tested with eyes open (EO) and with eyes closed (EC). In each block, four separate conditions of heavy (H) or light (L) touch to either a left or to a right force sensor mounted on the respective side rail, as well as one condition of no touch (N), were randomly applied. The 3D positions of the center of mass (COM) and the midpoint of the posterior aspect of each leg were monitored via a kinematic ultrasonic system, while the anterior-posterior (AP) acceleration of the COM was measured with a uniaxial linear accelerometer. RESULTS Light touch had a similar stabilizing effect as vision and as heavy touch on COM sway. Thus, COM sway and AP acceleration were comparable in conditions of eyes open and eyes closed as long as touch was applied. Conversely, without vision and touch, subjects drifted backwards, with complete disruption of the coordinated stepping pattern. CONCLUSIONS Somatosensory fingertip input from an external reference provides spatial orientation, which, similar to vision, enables the sustaining of body stability during treadmill walking.

[1]  M. Nicholls,et al.  A left hemisphere, but not right hemispace, advantage for tactual simultaneity judgments , 2000, Perception & psychophysics.

[2]  Adar Pelah,et al.  Visuomotor adaptation without vision? , 1999, Experimental Brain Research.

[3]  W. Siler,et al.  Grasping the handrails during treadmill walking does not alter sagittal plane kinematics of walking. , 1997, Archives of physical medicine and rehabilitation.

[4]  M S Redfern,et al.  Postural sway with earth-fixed and body-referenced finger contact in young and older adults. , 1999, Journal of vestibular research : equilibrium & orientation.

[5]  E. Macaluso,et al.  Spatial attention and crossmodal interactions between vision and touch , 2001, Neuropsychologia.

[6]  Mary C Verstraete,et al.  Modulation of head movement control in humans during treadmill walking. , 2002, Gait & posture.

[7]  F B Horak,et al.  Fingertip touch improves postural stability in patients with peripheral neuropathy. , 2001, Gait & posture.

[8]  F. Plum.  Handbook of Physiology. , 1960 .

[9]  J. Lackner,et al.  Coupling of fingertip somatosensory information to head and body sway , 1997, Experimental Brain Research.

[10]  F. Horak,et al.  Precision contact of the fingertip reduces postural sway of individuals with bilateral vestibular loss , 1999, Experimental Brain Research.

[11]  Paul DiZio,et al.  Stabilization of posture by precision touch of the index finger with rigid and flexible filaments , 2001, Experimental Brain Research.

[12]  S. Hsiao.  SIMILARITIES BETWEEN TOUCH AND VISION , 1998 .

[13]  J. Jeka,et al.  Light touch contact as a balance aid. , 1997, Physical therapy.

[14]  S. Jeng,et al.  Head stability in walking in children with cerebral palsy and in children and adults without neurological impairment. , 1999, Physical therapy.

[15]  Tim Kiemel,et al.  Multisensory information for human postural control: integrating touch and vision , 2000, Experimental Brain Research.

[16]  J. Konczak.  Effects of optic flow on the kinematics of human gait: a comparison of young and older adults. , 1994, Journal of motor behavior.

[17]  Alan M. Wing,et al.  Light touch contribution to balance in normal bipedal stance , 1999, Experimental Brain Research.

[18]  G. Mallis,et al.  The effect of limited handrail support on total treadmill time and the prediction of vo2 max , 1994, Clinical cardiology.

[19]  W. Berger,et al.  Visual influence on human locomotion Modulation to changes in optic flow , 1997, Experimental Brain Research.

[20]  S. Christman,et al.  Continuous handrail support, oxygen uptake, and heart rate in women during submaximal step treadmill exercise. , 2000, Research in nursing & health.

[21]  Kelvin S. Oie,et al.  Position and velocity coupling of postural sway to somatosensory drive. , 1998, Journal of neurophysiology.

[22]  Vladimir M. Zatsiorsky.  Kinematics of human motion , 1998 .

[23]  Mark W. Rogers,et al.  Passive tactile sensory input improves stability during standing , 2001, Experimental Brain Research.

[24]  D. Kerrigan,et al.  The vertical displacement of the center of mass during walking: a comparison of four measurement methods. , 1998, Journal of biomechanical engineering.