Ipsilateral sensory feedback in soleus EMG activity during stair ascent
Author
Andersen, Andreas Buus
Term
4. term
Publication year
2022
Pages
14
Abstract
Sensory afferent feedback helps maintain stable and efficient locomotion, yet its role during stair ascent is less understood. This study examined how ipsilateral sensory feedback contributes to motoneuronal drive and corrective stretch reflexes in the soleus during stair climbing. Participants ascended a custom seven-step staircase in which the fourth step was unexpectedly perturbed on selected trials: a vertical drop (before foot contact), a “horizontal” perturbation simulated by dropping only an outer section of the tread, and an unloading perturbation triggered after foot contact. Surface EMG was recorded from the left soleus and tibialis anterior along with foot contact and ankle kinematics. Thirteen volunteers were recruited for the vertical/horizontal protocols (eight analyzed after exclusions) and ten for the unloading protocol (four completed). Vertical perturbations elicited soleus responses that scaled positively with ankle angular velocity at perturbation onset, and horizontal perturbations produced a significant increase in the medium-latency reflex amplitude in soleus. Unloading perturbations did not yield consistent effects and warrant further investigation. Overall, the findings indicate that ipsilateral sensory feedback contributes to reflexive control of the ankle extensors during stair ascent, with notable engagement of medium-latency components.
Sensorisk afferent feedback er central for stabil og effektiv gang, men dens rolle under trappeopstigning er mindre belyst. Dette studie undersøgte, hvordan ipsilateral sensorisk feedback bidrager til det motoneuronale drive og korrigerende strækreflekser i soleus under trappeopstigning. Deltagere besteg en specialbygget syvtrins trappe, hvor fjerde trin uventet blev forstyrret på udvalgte forsøg: et lodret drop (før fodkontakt), en “horisontal” forstyrrelse simuleret ved et kantdrop af en del af trinfladen, samt en aflæsningsforstyrrelse udløst efter fodisæt. Overflade-EMG fra venstre soleus og tibialis anterior, fodkontakt og ankelkinematik blev registreret. Tretten personer blev rekrutteret til de lodrette/horisontale forløb (otte inkluderet i analyserne efter eksklusioner), og ti til aflæsningsforløbet (fire gennemførte). Lodrette forstyrrelser fremkaldte soleus-responser, der skalerede positivt med ankelhastigheden ved forstyrrelsens start, og horisontale forstyrrelser gav en signifikant forøgelse af den medium-latente refleksamplitude i soleus. Aflæsningsforstyrrelser gav ingen entydige effekter og kræver videre undersøgelse. Resultaterne peger på, at ipsilateral sensorisk feedback bidrager til refleksiv regulering af ankelstrækkere under trappeopstigning, med særligt engagement af medium-latente komponenter.
[This apstract has been generated with the help of AI directly from the project full text]