Diaphragm dysfunction, are refractory to drug therapy. This encourage investigators to explore new non-drug therapeutic paths, such as plantar reflexology (RP). The investigators proposed a comparison of the evolution of different parameters, quantitative and qualitative, to identify biomarkers and highlight the specific effect of RP on the diaphragm function, compared to placebo.

Many complex, chronic and multifactorial dysfunctions, such as diaphragm dysfunction, are refractory to drug therapy. This encourage investigators to explore new non-drug therapeutic paths, such as plantar reflexology (RP). This change is essential and will broaden relevant solutions to health.

Despite the very positive benefits of RP highlighted, the methodological quality of trials are often poor and there are gaps notably on the description of the intervention, the blind, the drop-out rate ... which prevents the meta-analyzes to conclude. Promoting rigorous research will play an essential role in the transition to personalized and integrative medicine. With the intention of specifying the methods of application and the indications of the PR, it is necessary to correctly evaluate and be able to cross-check the different information It therefore seems relevant to combine research on the objective physiological effects in correlation with the patient's subjective feelings to initiate the scientific validation of RP and thus non-drug interventions as recommended by the High Authority for Health (HAS). The hypothesis is that through a comparison of the evolution of different parameters, quantitative and qualitative, this study will allow to identify biomarkers and highlight the specific effect of RP on the diaphragm function, compared to placebo.

Inclusion Criteria:

• Adult aged 20 to 40
• Healthy right-handed subject, attested by a score ≥ 8/10 on the Edinburgh manual laterality questionnaire
• Naive subject in Reflexology.

Exclusion Criteria:

• Contraindication to carrying out the MRI examination
• Subject refusing to be informed of any abnormality detected on brain MRI,
• Subject presenting a neurodegenerative disease,
• Subject presenting a cardiac disease,
• Subject presenting skin lesions in the feet or recent fracture in the feet,
• Subject having an history of phlebitis less than 3 months
• Subject having an history of deep vein thrombosis.

each participant has reflexology and placebo massage, he is his own comparator