Lying Dumbbell Tricep Extension: Lie on your back with your knees bent and feet flat against the floor. Keep your lower back pressed against the floor and raise your elbows in front of your chest at a 90-degree angle. Bend your arms at the elbow about 45 degrees so that your hands are slightly above your head. Extend your arms up towards the ceiling keeping the weight vertical until your elbow reaches 90 degrees. Now turn the palms up causing the weights to be in the horizontal position and extend fully upwards. Keep the elbows steady as you are extending and focus on the contraction of the Triceps Muscle. Reverse slowly back to the start position and repeat.