eprintid: 10046090
rev_number: 31
eprint_status: archive
userid: 608
dir: disk0/10/04/60/90
datestamp: 2018-04-06 13:17:59
lastmod: 2020-05-15 08:45:19
status_changed: 2018-04-06 13:17:59
type: article
metadata_visibility: show
creators_name: Lorentzen, J
creators_name: Willerslev-Olsen, M
creators_name: Hüche Larsen, H
creators_name: Svane, C
creators_name: Forman, C
creators_name: Frisk, R
creators_name: Farmer, SF
creators_name: Kersting, U
creators_name: Nielsen, JB
title: Feedforward neural control of toe walking in humans
ispublished: pub
subjects: UCH
divisions: UCL
divisions: A01
divisions: B02
divisions: C07
divisions: D07
keywords: Ischemia, TMS, Ultrasound, Toe walking
note: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions.
abstract: Toe walking requires careful control of the ankle muscles in order to absorb the impact of ground contact and maintain a stable position of the joint. The present study aimed to clarify the peripheral and central neural mechanisms involved. Fifteen healthy adults walked on a treadmill (3.0 km h-1). Tibialis Anterior (TA) and Soleus (Sol) EMG, knee and ankle joint angles and gastrocnemius-soleus muscle fascicle lengths were recorded. Peripheral and central contributions to the EMG activity were assessed by afferent blockade, H-reflex testing, Transcranial Magnetic Brain Stimulation (TMS) and sudden unloading of the planter flexor muscle-tendon complex. Sol EMG activity started prior to ground contact and remained high throughout stance. TA EMG activity, which is normally seen around ground contact during heel strike walking, was absent. Although stretch of the Achilles tendon-muscle complex was observed after ground contact, this was not associated with lengthening of the ankle plantar flexor muscle fascicles. Sol EMG around ground contact was not affected by ischemic blockade of large diameter sensory afferents, or the sudden removal of ground support shortly after toe contact. Soleus motor evoked potentials elicited by TMS were facilitated immediately after ground contact, whereas Sol H-reflexes were not. These findings indicate that at the crucial time of ankle stabilisation following ground contact, toe walking is governed by centrally mediated motor drive rather than sensory driven reflex mechanisms. These findings have implications for our understanding of the control of human gait during voluntary toe walking.
date: 2018-06-01
date_type: published
official_url: https://doi.org/10.1113/JP275539
oa_status: green
full_text_type: other
language: eng
primo: open
primo_central: open_green
verified: verified_manual
elements_id: 1546763
doi: 10.1113/JP275539
lyricists_name: Farmer, Simon
lyricists_id: SFFAR49
actors_name: Farmer, Simon
actors_id: SFFAR49
actors_role: owner
full_text_status: public
publication: Journal of Physiology
volume: 596
number: 11
pagerange: 2159-2172
event_location: England
issn: 1469-7793
citation:        Lorentzen, J;    Willerslev-Olsen, M;    Hüche Larsen, H;    Svane, C;    Forman, C;    Frisk, R;    Farmer, SF;         ... Nielsen, JB; + view all <#>        Lorentzen, J;  Willerslev-Olsen, M;  Hüche Larsen, H;  Svane, C;  Forman, C;  Frisk, R;  Farmer, SF;  Kersting, U;  Nielsen, JB;   - view fewer <#>    (2018)    Feedforward neural control of toe walking in humans.                   Journal of Physiology , 596  (11)   pp. 2159-2172.    10.1113/JP275539 <https://doi.org/10.1113/JP275539>.       Green open access   
 
document_url: https://discovery.ucl.ac.uk/id/eprint/10046090/1/Feedforward%20neural%20control%20of%20toe%20walking%20in%20humans%20%20March%202018.pdf