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Improved postural control after slackline training is accompanied by reduced H‐reflexes
Author(s) -
Keller M.,
Pfusterschmied J.,
Buchecker M.,
Müller E.,
Taube W.
Publication year - 2012
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/j.1600-0838.2010.01268.x
Subject(s) - reflex , h reflex , physical medicine and rehabilitation , balance (ability) , electromyography , medicine , balance training , soleus muscle , afferent , psychology , physical therapy , neuroscience , anesthesia , anatomy , skeletal muscle
“Slacklining” represents a modern sports activity where people have to keep balance on a tightened ribbon. The first trials on the slackline result in uncontrollable lateral swing of the supporting leg. Training decreases those oscillations and therefore improves postural control. However, the underlying neural mechanisms are not known. Therefore, the present study aimed to highlight spinal adaptations going along with slackline training. Twenty‐four subjects were either assigned to a training or a control group and postural control was assessed before and after the 10 training sessions. Additionally, soleus Hoffmann (H)‐reflexes were elicited to evaluate changes in the excitability of the spinal reflex circuitry. Trained subjects were able to maintain balance on the slackline for at least 20 s ( P <0.001) and reduced platform movements on the balance board ( P <0.05). The H‐reflexes were significantly diminished ( P <0.05) while no changes occurred in the background electromyography (bEMG). The control group showed no significant changes. From a functional point of view the reflex reduction may serve to suppress uncontrollable reflex mediated joint oscillations. As the bEMG remained unchanged, presynaptic rather than post‐synaptic mechanisms are speculated to be responsible for the changes in the Ia‐afferent transmission.