PMID- 25085609
OWN - NLM
STAT- MEDLINE
DCOM- 20150409
LR  - 20191008
IS  - 1522-1598 (Electronic)
IS  - 0022-3077 (Linking)
VI  - 112
IP  - 3
DP  - 2014 Aug 1
TI  - Neuromechanical interference of posture on movement: evidence from Alexander
      technique teachers rising from a chair.
PG  - 719-29
LID - 10.1152/jn.00617.2013 [doi]
AB  - While Alexander technique (AT) teachers have been reported to stand up by
      shifting weight gradually as they incline the trunk forward, healthy untrained
      (HU) adults appear unable to rise in this way. This study examines the hypothesis
      that HU have difficulty rising smoothly, and that this difficulty relates to
      reported differences in postural stiffness between groups. A wide range of
      movement durations (1-8 s) and anteroposterior foot placements were studied under
      the instruction to rise at a uniform rate. Before seat-off (SO) there were clear 
      and profound performance differences between groups, particularly for slower
      movements, that could not be explained by strength differences. For each movement
      duration, HU used approximately twice the forward center-of-mass (CoM) velocity
      and vertical feet-loading rate as AT. For slow movements, HU violated task
      instruction by abruptly speeding up and rapidly shifting weight just before SO.
      In contrast, AT shifted weight gradually while smoothly advancing the CoM,
      achieving a more anterior CoM at SO. A neuromechanical model revealed a mechanism
      whereby stiffness affects standing up by exacerbating a conflict between postural
      and balance constraints. Thus activating leg extensors to take body weight
      hinders forward CoM progression toward the feet. HU's abrupt weight shift can be 
      explained by reliance on momentum to stretch stiff leg extensors. AT's smooth
      rises can be explained by heightened dynamic tone control that reduces leg
      extensor resistance and improves force transmission across the trunk. Our results
      suggest postural control shapes movement coordination through a dynamic "postural
      frame" that affects the resistive behavior of the body.
CI  - Copyright (c) 2014 the American Physiological Society.
FAU - Cacciatore, Timothy W
AU  - Cacciatore TW
AD  - UCL Institute of Neurology, London, United Kingdom.
FAU - Mian, Omar S
AU  - Mian OS
AD  - UCL Institute of Neurology, London, United Kingdom.
FAU - Peters, Amy
AU  - Peters A
AD  - UCL Institute of Neurology, London, United Kingdom.
FAU - Day, Brian L
AU  - Day BL
AD  - UCL Institute of Neurology, London, United Kingdom brian.day@ucl.ac.uk.
LA  - eng
GR  - G0802073/Medical Research Council/United Kingdom
GR  - 084870/Z/08/Z/Wellcome Trust/United Kingdom
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20140514
PL  - United States
TA  - J Neurophysiol
JT  - Journal of neurophysiology
JID - 0375404
SB  - IM
MH  - Adult
MH  - Aged
MH  - Exercise Movement Techniques/*methods
MH  - Female
MH  - Humans
MH  - Leg
MH  - Male
MH  - Middle Aged
MH  - Models, Neurological
MH  - Movement/*physiology
MH  - Muscle, Skeletal/physiology
MH  - Postural Balance/physiology
MH  - Posture/*physiology
MH  - Professional Competence
MH  - Torso
PMC - PMC4122698
OTO - NOTNLM
OT  - Alexander technique
OT  - balance
OT  - movement
OT  - muscle tone
OT  - posture
OT  - sit-to-stand
EDAT- 2014/08/03 06:00
MHDA- 2015/04/10 06:00
CRDT- 2014/08/03 06:00
PHST- 2014/08/03 06:00 [entrez]
PHST- 2014/08/03 06:00 [pubmed]
PHST- 2015/04/10 06:00 [medline]
AID - jn.00617.2013 [pii]
AID - 10.1152/jn.00617.2013 [doi]
PST - ppublish
SO  - J Neurophysiol. 2014 Aug 1;112(3):719-29. doi: 10.1152/jn.00617.2013. Epub 2014
      May 14.