Chest: Run a tape measure around the fullest part of the chest and measure. Then hold the point where the measurement was taken on the tape measure and lay it horizontally to determine it
Waist: Holding a tape measure horizontally, measure your waist circumference at the narrowest point, i.e. where your torso tilts when you bend to the side.
Hips: Standing straight with your feet together, hold the tape horizontally, and measure the circumference of your hips at the widest point.
N.B.: the garment you receive may have EU sizing on the external label, as Diadora is an Italian brand. During the purchase phase, simply select your size; it will already be converted for your country of residence (US). If you are not satisfied with the fit, remember that returns are free.