PENS
DeviceThe participants underwent one 30-min session every week for 12 consecutive weeks. PENS was delivered by a needle electrode inserted in the medioclavicular line, 2 cm below the clavicle at a 90° angle towards the skin at a depth of approximately 1 cm. PENS was undertaken at frequency of 20 Hz at the highest amplify (0-20 mA) without causing pain. PENS was delivered simultaneously in both pectoral muscles.