Modulation of the Hoffmann reflex in the tibialis anterior with a change in posture

Physiological Reports

Doug W. Renshaw¹  Janelle Unger¹  Jonathan P. Farthing¹  Justin W. Andrushko¹  Alison R. Oates¹  Trevor S. Barss²  E. Paul Zehr² 

[1] College of Kinesiology University of Saskatchewan Saskatoon Saskatchewan Canada;Rehabilitation Neuroscience Laboratory, Physical and Health Education University of Victoria Victoria British Columbia Canada;

关键词: H‐reflex;    postural control;    reflex modulation;   

DOI  :  10.14814/phy2.14179

来源: DOAJ

【 摘 要 】

Abstract Hoffmann (H‐) reflex amplitudes in plantar flexor soleus muscle are modulated by posture, yet dorsiflexor tibialis anterior (TA) H‐reflex parameters have sparingly been studied. The purpose was to investigate modulation of the TA H‐reflex when postural demands are increased from sitting to standing. In this study, data from 18 participants (Age: 25 ± 4 years, Height: 170.9 ± 9.5 cm, Weight: 75.9 ± 17.2 kg) allowed comparison of two experimental conditions involving different postures (i.e. sitting and standing). Maximal amplitude of the TA H‐reflex (Hmax) as a percent of the maximal M‐wave amplitude (Mmax) (Hmax (% Mmax)) during sitting and standing was compared using ANOVA. Modulation of TA H‐reflex amplitude was found: Eleven participants showed facilitation and seven showed no change of reflex amplitudes. Only participants in the facilitation group showed modulation related to changes in posture (sitting: 8.7 ± 2.9%; standing: 14.8 ± 6.7%, P = 0.005). These data provide evidence of the sensitivity to posture of TA H‐reflexes. As with task‐dependent changes in soleus H‐reflexes, presynaptic regulation of Ia afferent transmission is a possible mechanism. Further investigations into causes of modulation are warranted.

【 授权许可】

Unknown