1- Sit on a bench holding a dumbbell between your feet, palm facing forward and the elbow positioned against the inner thigh.
2- Inhale and raise the dumbbell by bending the elbow.
3- Exhale at the end of the effort and lower the dumbbell until arm is fully extended, and repeat.
Tips and Advices:
Make sure that your back remains stationary though out the movement, supported by your free hand on the opposite thigh.
Variation:
One Arm Biceps Cable Curl