The main objective is to assess the effect, compared to usual care, of a nursing accompaniment or nursing assistant intervention in the physical activity of patients hospitalized in the geriatric stay, on the daily number of steps.

The secondary objectives consist in evaluating the effect, compared to usual care, of a nursing or nursing assistant's intervention in physical activity of elderly patients hospitalized on a short geriatric stay in terms of:

• The change of the daily physical exertion in metabolic equivalent
• The change of the daily number of steps
• The change of care course
• The change of in falls occurrence
• The change of autonomy patient
• The change of travels habits

The aging of the French population leads to a significant increase in elderly hospitalizations. These patients are often dependent, polymorbid and precarious from a medical, social and economic point of view, bringing them into a frailty process to which the health system is trying to adapt. In fact, the absence of specific care adapted to frail elderly patients results in an increased risk of functional maladjustment. It is characterized by a loss, during hospitalization, of the ability to perform the activities of daily living alone and a decrease in physical activity. This maladjustment can differ or even prevent return home, increases the risk of falling, the length of stay and health expenses.

The concept of frailty in the elderly is mainly based on the concept of physical vulnerability, and in particular muscular vulnerability. Increasing attention is therefore being paid to physical activity in the elderly, which can prevent the process of maladjustment.

The 2004802 Decree of July 29, 2004 recalls that nurses lift patients and help them to walk without using rehabilitation techniques, to ensure their comfort. The interest of such an approach has already been reported, especially in primary care where nursing support allows a sustained and lasting increase in physical activity in the elderly. To the best of the investigators' knowledge, the effectiveness of such a nursing approach to physical activity support has not been studied in hospitals yet.

The investigators looked for exercises simple, fast and adapted to an elderly population with a very diverse functional maladjustment. The selected intervention is a physical activity based on the activities of daily living to improve postural balance and strengthening the muscles of the lower limbs. This intervention follows the main principles of the latest recommendations of the French High Authority for Health on the elderly fall prevention. It resumes acts such as sitting or standing on a foot corresponding to static equilibrium conditions. It also proposes carrying out transfers from a sitting to standing position and from a standing to sitting position corresponding to motor acts for the lower limbs.

The investigators hypothesize that formalized paramedical support in a geriatric short-stay service prevents the elderly from decreasing their physical activity, and prevents the occurrence of falls and early re-hospitalization.

Inclusion Criteria:

• Men or women ≥ 75 years old
• Hospitalization in geriatric short stay
• Informed and express (oral) consent to participate in the study by the patient or the patient's representative
• Affiliation to French Social Security.

Exclusion Criteria:

• Neurological or orthopedic pathology that prevents the performance of one or more exercises corresponding to the patient's level of risk of falling
• Short expected hospital stay
• Contraindication to physical activity
• Person subject to a safeguard of justice measure
• Patient who previously participated to the study.