Light touch contribution to balance in normal bipedal stance

Area of Science:

• Biomechanics
• Human Motor Control
• Neuroscience

Background:

• Light fingertip contact on a surface has been shown to reduce center of pressure (CoP) fluctuations in the frontal plane during unstable stances (tandem Romberg).
• Previous findings suggest that sensory input from the hand contributes to postural stability through positive cross-correlations between horizontal finger forces and CoP fluctuations.

Purpose of the Study:

• To investigate the effect of light touch on postural stability during normal bipedal stance.
• To determine if hand touch input is beneficial for regulating normal upright posture.

Main Methods:

• Participants performed normal bipedal stance and tandem Romberg stance.
• Center of pressure (CoP) fluctuations were measured with and without light fingertip contact.
• Cross-correlations between horizontal finger forces and CoP fluctuations were analyzed.

Main Results:

• Light fingertip touch significantly reduced CoP fluctuations in the sagittal plane during normal bipedal stance.
• Positive cross-correlations were observed between finger tip forces and CoP fluctuations, similar to those in unstable stances.
• The findings indicate that hand touch provides sensory input for postural control in normal stance.

Conclusions:

• Light touch input via the fingertips enhances postural control in normal upright stance.
• The hand's sensory contribution to stability is significant for both normal and unstable postures.
• This study highlights the importance of upper limb sensory feedback for maintaining balance.