PMID- 24374058
OWN - NLM
STAT- MEDLINE
DCOM- 20141007
LR  - 20140210
IS  - 1872-7972 (Electronic)
IS  - 0304-3940 (Linking)
VI  - 561
DP  - 2014 Feb 21
TI  - Particular adaptations to potentially slippery surfaces: the effects of friction 
      on consecutive postural adjustments (CPA).
PG  - 24-9
LID - S0304-3940(13)01080-X [pii]
LID - 10.1016/j.neulet.2013.12.008 [doi]
AB  - This research deals with the postural adjustments that occur after the end of 
      voluntary movement ("consecutive postural adjustments": CPAs). The influence of a 
      potentially slippery surface on CPA characteristics was considered, with the aim 
      of exploring more deeply the postural component of the task-movement. Seven male 
      adults were asked to perform a single step, as quickly as possible, to their own 
      footprint marked on the ground. A force plate measured the resultant reaction 
      forces along the antero-posterior axis (R(x)) and the centre of pressure (COP) 
      displacements along the antero-posterior and lateral axes (Xp and Yp). The 
      velocity of the centre of gravity (COG) along the antero-posterior axis and the 
      corresponding impulse (integralR(x)dt) were calculated; the peak velocity (termed 
      "progression velocity": V(xG)) was measured. The required coefficient of friction 
      (RCOF) along the progression axis (pmu(x)) was determined. Two materials, 
      differing by their COF, were laid at foot contact (FC), providing a rough foot 
      contact (RoFC), and a smooth foot contact (SmFC) considered to be potentially 
      slippery. Two step lengths were also performed: a short step (SS) and a long step 
      (LS). Finally, the subjects completed four series of ten steps each. These were 
      preceded by preliminary trials, to allow them to acquire the necessary adaptation 
      to experimental conditions. The antero-posterior force time course presented a 
      positive phase, that included APAs ("anticipatory postural adjustments") and step 
      execution (STEP), followed by a negative one, corresponding to CPAs. The backward 
      impulse (CPI) was equal to the forward one (BPI), independently of friction and 
      progression velocity. Moreover, V(xG) did not differ according to friction, but 
      was faster when the step length was greater. Last CPA peak amplitudes (pCPA) were 
      significantly greater and CPA durations (dCPA) shorter for RoFC and conversely 
      for SmFC, contrary to APA. Finally, the results show a particular adaptation to 
      the potentially slippery surface (SmFC). They suggest that adherence modulation 
      at foot contact could be one of the rules for controlling COG displacement in 
      single stepping. Consequently, the actual coefficient of friction value might be 
      implemented in the motor programme at a higher level than the voluntary movement 
      specific parameters.
CI  - Copyright (c) 2013 Elsevier Ireland Ltd. All rights reserved.
FAU - Memari, Sahel
AU  - Memari S
AD  - Complexite, Innovation, Activites Motrices et Sportives (CIAMS), Universite 
      Paris-Sud, F-91405 Orsay, France.
FAU - Le Bozec, Serge
AU  - Le Bozec S
AD  - Complexite, Innovation, Activites Motrices et Sportives (CIAMS), Universite 
      Paris-Sud, F-91405 Orsay, France. Electronic address: serge.le-bozec@u-psud.fr.
FAU - Bouisset, Simon
AU  - Bouisset S
AD  - Physiologie du Mouvement, Universite Paris-Sud, F-91405 Orsay, France.
LA  - eng
PT  - Journal Article
DEP - 20131225
PL  - Ireland
TA  - Neurosci Lett
JT  - Neuroscience letters
JID - 7600130
SB  - IM
MH  - Adult
MH  - Anticipation, Psychological
MH  - *Friction
MH  - Humans
MH  - Male
MH  - *Movement
MH  - *Postural Balance
MH  - *Posture
OTO - NOTNLM
OT  - Anticipatory postural adjustments (APAs)
OT  - Consecutive postural adjustments (CPAs)
OT  - Postural control
OT  - Required coefficient of friction (RCOF)
OT  - Single stepping
OT  - Slippery surface
EDAT- 2014/01/01 06:00
MHDA- 2014/10/08 06:00
CRDT- 2013/12/31 06:00
PHST- 2013/08/28 00:00 [received]
PHST- 2013/11/17 00:00 [revised]
PHST- 2013/12/05 00:00 [accepted]
PHST- 2013/12/31 06:00 [entrez]
PHST- 2014/01/01 06:00 [pubmed]
PHST- 2014/10/08 06:00 [medline]
AID - S0304-3940(13)01080-X [pii]
AID - 10.1016/j.neulet.2013.12.008 [doi]
PST - ppublish
SO  - Neurosci Lett. 2014 Feb 21;561:24-9. doi: 10.1016/j.neulet.2013.12.008. Epub 2013 
      Dec 25.