An electromyographic study of isokinetic axial rotation in young adults

Changes in axial stiffness of the trunk as a function of walking speed

“…It was concluded that the return movement is mostly due to elastic recoil. In a later study, it was found that the contribution of active muscle contraction to axial torque decreases as the angular velocity increases indicating the increasing role of elastic energy stored in connective tissues during isokinetic axial rotation of trunk (Kumar et al, 2003).…”

Oblique abdominal muscle activity in response to external perturbations when pushing a cart

“…In the pushing while standing condition, oblique abdominal muscle activity produced spinal moments in the sagittal plane only as twisting moments were close to zero. The static level muscle activity in dynamic pushing, which equalled the peak level in pushing while standing thus appeared to be necessary to produce these moments when pushing while walking, while the additional dynamic activity was associated with the twisting moments, which were actively modulated by the pairs of EO and IO muscles, as in gait (Callaghan et al, 1999;Kumar et al, 2003). Trunk twisting moments in normal gait cause an angular momentum of the upper body opposite to that of the lower body (Bruijn et al, 2008).…”

“…This implies that trunk muscles create a twisting moment that is opposite to the moment resulting from the push-off forces. External oblique (EO) and internal oblique (IO) muscles are the main contributors to twisting moments (Dumas et al, 1991;Ng et al, 2001;Kumar et al, 2003) and these muscles are cyclically active during normal gait (Callaghan et al, 1999).…”

Control of the lateral abdominal muscles during walking

“…The other f 2 peaks of TA and OI occurred at contralateral heel contact, approximately simultaneous with the peak in the ipsilateral rotation moment (Fig. 1), suggesting that TA and OI acted as ipsilateral rotators (Benninghoff & Goerttler, 1964;Hodges, 2008;Kumar, Narayan, & Garand, 2003).…”