Does the Attitude toward a Heavy Lifting Motion Change when Instructed to Use a Squat Method? Focusing on Lifting an Object

Abstract

Objective：To investigate the effects of being instructed to use a squat method on posture and the joints involved in the pelvic position.

Methods：The subjects were 15 healthy men (mean age, 23.8 ± 1.0 years)．We set free and squat conditions as the measurement tasks and instructed the subjects to lift an object from the floor. Differences in joint angles between the two conditions at the time the object left the floor were examined using a corresponding t test. To assess the joints that affect the pelvic anterior tilt angle, lumbar and limb joint angles and the correlation coefficient between them were calculated.

Results：In the squat condition, the extension angles of the thoracic vertebrae, upper and lower thoracolumbar transitional vertebrae, and upper lumbar vertebrae；the pelvic posterior tilt angle；flexion angles of the hip and knee joints；and dorsiflexion angle of the ankle joint increased. The pelvic anterior tilt angle was related to the knee and ankle joint angles in both conditions.

Conclusion：Instructions to use a squat method increased the trunk extension and leg flexion angles. In both conditions, the knee and ankle joints affect the pelvic anterior tilt angle.