Cable seated one arm concentration curl

Sit on a bench with your feet flat on the floor and your back straight. Hold a cable handle with one hand and place your elbow on the inside of your thigh, just above the knee. Keep your upper arm stationary and curl the cable handle towards your shoulder while exhaling. Pause for a moment at the top of the movement, squeezing your biceps. Slowly lower the cable handle back to the starting position while inhaling. Repeat for the desired number of repetitions, then switch arms.