Diaphragm Movement During Its Postural Function

Diaphragm movement will be measured by m-mode ultrasonography in a standing position. 30-35 healthy subjects will participate in the study. The movement of the diaphragm will be measured during tidal breathing then, during holding a load corresponding to 20% of the subject´s body weight and finally, during voluntary contraction of the trunk muscles. Trunk muscles contraction will be measured by a special device with pressure sensors placed on a trunk surface. Breathing activity will be measured by spirometry.

Inclusion criteria

• Signed informed consent form
• Able to comply with the study protocol, in the investigator's judgment
• Aged 20-40 years, inclusive
• Healthy as determined by the Investigator based on medical history, physical examination, vital signs and neurological examination
• Waist-to-height ratio < 0,59

Exclusion criteria

• Low back pain (acute or chronic)
• Previous abdominal or spine surgery
• Acute or chronic respiratory or musculoskeletal disorder
• Any clinically significant illness, medical/surgical procedure or trauma within 4 weeks before initiation of the study
• Pregnancy