Sarcopenia is known to be associated with loss in muscle mass that results from a reduced number of muscle fibres, an atrophy of remaining muscle fibres, and an increased infiltration of non-contractile tissue (collagen, fat). Accentuated by cancer and treatments, sarcopenia impairs muscle function resulting in a higher risk of physical disability and death. The commonly used test for sarcopenia screening consists in a DEXA (Dual energy X-ray absorptiometry) scan. However, this test can't provide structural muscle information. In contrast, the mechanical properties of muscle tissue can be explored using an acoustic radiation force impulse (ARFI). The question remains whether muscle sonoelastography using ARFI imaging could be helpful for sarcopenia screening.

For this, volunteers will be recruited in three groups: ≤ 30 years (Gr A) and ≥ 70years, both without any serious chronic disease, and patients ≥ 70 years presenting curative cares for cancer (Gr C).

The volunteers belonging to the groups A and B will be followed during one day. The patients included in the group C will be followed during 6 months. For this latter group; the first visit (t0) will take place before treatment and the second visit will take place 6 months later (t6months) Volunteers will have clinical examinations (weight, stature, BMI, performance status/ ECOG) and will be evaluated on their nutritional status (MNA-SF, 24h dietary recall) and physical capacities (IPAQ, SPPB, lower limb muscle strength, 6-min walk test, QLQ-C30 items relative to the fatigue symptom).

Inclusion Criteria:

• Men or women 18 years old or more,
• Able to understand the protocol and to give their written consent,
• Health insurance.

Specific inclusion criteria:

• Group A: volunteers 18 to 30 yrs; without any pathology,
• Group B: volunteers ≥ 70 yrs; without any pathology,
• Group C: Performance status (ECOG) < 4; patients included in CAPADOGE study presenting curative cares for cancer by chemotherapy and/ or surgery and/or hormonotherapy and/or radiotherapy.

Exclusion Criteria:

• Intense activity in 7 preceding days,
• Functional dependency,
• under a legal protection.

Specific non-inclusion criteria:

• Groups A & B: serious chronic disease,
• Group C: Palliative care.