Alain Hamaoui

 

Alain Hamaoui
Professeur des Universités
alain.hamaoui @ u-psud.fr

Equipe MHAPS

 

 Research area

Mobility of the postural chain and posturo-kinetic capacity

According to the concept of posturo-kinetic capacity (Bouisset and Zattara, 1983), the execution of a voluntary movement is associated with internal disturbances which challenge body balance. These disturbances needs to be at least partly compensated for, involving counter disturbing movements located along the postural chain.

Current research are aimed to characterize the effect of different kinds (reduction of range of motion, increased muscular tension) and locations (spine, peripheral joints) of  mobility restrictions on simple or complex motor tasks (sit-to-stand, pointing,…) (Hamaoui et Rodrigues, 2017). In a perspective of improving therapeutic strategies in rehabilitation and manual therapy, the effect of manual joint mobilization aimed at restoring joint mobility are also explored (Ditcharles et al., 2017).

Interaction between posture and respiration

The human capacity to stand erect, despite the elevated height of the center of gravity and a reduced pressure zone, has drawn scientific interest for centuries. In recent decades, scientific research has demonstrated that the human body not only counters the effect of gravity, but also counterbalances a certain number of endogenous disturbances, such as respiration or cardiac rhythms (Gurfinkel et al., 1971, Bouisset and Duchêne, 1994).

My research focuses on features and effects of these disturbances, as well as the modalities of their compensation. Attention is currently given to the specific effect of the diaphragm contraction in healthy subjects -(Hamaoui et al., 2014) and in patients, including the investigation of biomechanical markers in diaphragm unilateral palsy (collaborative project with Pr Similowski at Pitié-Salpétrière hospital).

Analysis of centre of gravity acceleration and respiratory kinematics during phrenic nerve stimulations.  Biomechanical traces show that diaphragm contraction has a reverse effect in seated and standing postures, with CG acceleration directed towards and forwards, respectively.

Ergonomics of seated posture

Following the shift from the 20th century industrial society to nowday’s digitally-connected society, sitting has become the most common posture at work and also during the time increasingly devoted to leisure and learning. Sitting from long period is associated with the risk of developing back pain (Hoy et al., 2010), and finding the best posture and seat to reduce the stress undergone par the body is an important health issue. Ongoing research investigate the effect of seat ergonomics (backrest slope, foam density...) (Hamaoui et al., 2015) on biomechanical variable while sitting quietly and also during performing different tasks. Special attention is given to air plane seat and to the seated posture of musicians.

 Selected publications

Hamaoui, A., & Alamini-Rodrigues, C. (2017). Influence of Cervical Spine Mobility on the Focal and Postural Components of the Sit-to-Stand Task. Frontiers in Human Neuroscience, 11, 129

Ditcharles, S., Yiou, E., Delafontaine, A., & Hamaoui, A. (2017). Short-Term Effects of Thoracic Spine Manipulation on the Biomechanical Organisation of Gait Initiation: A Randomized Pilot Study. Frontiers in Human Neuroscience, 11, 343.

Hamaoui, A., Hassaïne, M., & Zanone, P.-G. (2015). Sitting on a sloping seat does not reduce the strain sustained by the postural chain. PloS One, 10(1)

Hamaoui, A., Hudson, A. L., Laviolette, L., Nierat, M.-C., Do, M.-C., & Similowski, T. (2014). Postural disturbances resulting from unilateral and bilateral diaphragm contractions: a phrenic nerve stimulation study. Journal of Applied Physiology (Bethesda, Md.: 1985), 117(8), 825‑832.