#6 Alternating Hamstring Stretch
The alternating hamstring stretch wraps up our list of warm-up exercises. It is one of the best warm-up stretching exercises that you could perform to flex the upper leg.
Instructions
Step 1: Stand straight and keep your feet at a distance that is approximately equal to the width of the shoulders.
Step 2: Extend the right leg forward, bend your knees and plant the heel firmly on the floor. Bend forward in the same direction and extend your arms fully such that they are almost parallel to the floor.
Step 3: Hold for a moment and return to the starting position. Repeat the same motion on the other side to complete one rep.
Perform the exercise for two minutes.
Important tip: Beginners should avoid taking a huge stride as it could lead to a muscle pull.