Allow your heels to lower towards the floor to get a good stretch and make sure you push all the way up to the top of the range of motion also. (best-leg-exercises.com)
If you don't fully extend your arms at the end of the range of motion of the movement, meaning at the lowest point of the curl, you are selling yourself short. (fitnessandpower.com)
It was apparent that in the bottom part of the range of motion, there was minimal resistance and, therefore, this set - up was not likely to be very effective. (ageless-athletes.com)