Among the repercussions of hemiparesis following stroke, disturbed stability is responsible for a high risk of falls. Picking up objects from the ground, frequently trained in rehabilitation due to its risk of falling and its frequency in daily life, is a task requiring balance. To date, however, it has been little studied. We suggest that stability conditions the asymmetry adopted by patients. We hypothesise that asymmetric support at the expense of the paretic lower limb provides better stability during an unstable functional task (picking up an object from the ground) compared with the symmetrical support traditionally imposed in rehabilitation.

Postural control involves stability (maintaining balance despite constraints) and orientation (posture adopted, such as the distribution of supports). Hemiparetic patients show a lack of stability and, with regard to orientation, an asymmetry in the distribution of body weight to the detriment of the paretic limb. Symmetrisation of weight distribution has been one of the predominant concepts in rehabilitation.

To analyse the stability of hemiparetic stroke patients when picking up an object on the ground in a spontaneous condition compared with a condition of imposed support symmetry.

To analyse and compare the stability, spontaneous symmetry and duration of picking up the object in a complex situation (distant target) compared with the near target in stroke patients and healthy subjects.

To explore strategy and performance of picking up the object regarding clinical outcomes (falls, sensori-motor impairments, balance..) To compare strategy of patients with right and left stroke.

Inclusion Criteria:

All:

Male or female ≥ 18 years

For patients :

• Haemiparesis after a single unilateral hemispheric Stroke.
• Stroke ≥ 6 months
• Asymmetry of support between the 2 lower limbs (distribution of body weight) in a standing position at the expense of the paretic lower limb > 10%.
• Able to stand alone, without technical aids or equipment, with feet the width of the pelvis
• Able to pick up an object from the ground alone (minimum score 3/4 item 9 of the Berg Balance Scale).
• Patient informed and having signed a consent form

For healthy subjects:

- Similar characteristics (in terms of sex, age range and BMI class) to those of one of the patients already included.

Exclusion Criteria:

-

Hemiparetic patients following stroke; Healthy subjects (same age, height, weight).