Respiratory disturbance to posture varies according to the respiratory mode

Postural control and ventilatory drive during voluntary hyperventilation and carbon dioxide rebreathing

“…Data obtained from the force plate indicated that postural perturbations during VH in the transversal and sagittal planes ratio (DF z /DF x ) were the same order of magnitude as those measured during CO 2 -R. Insofar as the larger thoracic movements during VH did not correspond to any metabolic need, and that the breathing frequency was a controlled variable, the slight increase in CoP amplitude noticed in the lateral direction during VH, and not during CO 2 -R, can be regarded as a consequence of either a more disturbed posture or a less efficient postural control. The postural instability observed during VH can be related to an increase in the proportion of rib cage contribution to tidal volume, as reported elsewhere (Sackner et al 1984), and shown recently as more disturbing than the abdominal contribution (Hamaoui et al 2010). During VH, data in the time and spectral domains from the vertical ground reaction force (F z ) revealed an increase in the mean amplitude and a decrease in MPF, respectively.…”

Does increased muscular tension along the torso impair postural equilibrium in a standing posture?

“…The respiratory component of CP displacements was investigated in the frequency domain by means of a specifically designed peak detection algorithm and a respiratory emergence parameter, using the Fast Fourier Transform. This method has been extensively described elsewhere [7]. In brief, the respiratory peak along the anterior-posterior (RPX) and medial-lateral (RPY) axes, was considered as present in CP displacements when the following criteria were met: -Presence of local maximum at the respiratory frequency AE 0.02 Hz surrounded by at least two slopes of the same sign.…”

“…In addition to the alteration of the PKC, which is based on active counter-disturbing movements [15], higher muscular stiffening could also reduce the passive dampening capacity of the postural chain [7]. As a consequence, the transmission of the postural disturbances to the extremities of the postural chain and to the ground would be increased, leading to higher CP displacements.…”

“…In addition, increased tension of the pectoralis major muscle, which was the most sensitive to the compressive load, was likely to restrict the kinematics of the rib cage it is inserted into. Since it has been shown that thoracic breathing disturbs posture more than abdominal breathing does [7], the disturbing effect of respiration on body balance should be lessened.…”

“…The mobility of the postural chain is also required to compensate for the respiratory disturbance to posture, which involves the whole torso through rhythmic movements of the rib cage and the abdomen [4]. In this case, feed-forward counter-perturbing synergies could also occur [5,6], as well as simpler passive dampening phenomena [7].…”