Busy, busy, busy! Who has time to stretch? If you have 90 seconds, you do!
Sit forward in your chair, so you do not take support from the chair back, keep one leg bent and extend the other leg straight, rest that heel on the floor, toes pointing straight up. Hinge forward from your hips, keep your spine and knee straight. You should feel the stretch in the back of your thigh (the 1st picture in the series). Hold 30 seconds and sit up.
To get the other portions of the hamstrings, do the same steps as previously but have the straight leg rolled inward from the hip socket, the foot and leg should point toward the other leg (the 2nd picture in the series). Hold 30 seconds and sit up.
Finally, do the same steps as previously but now roll the leg outward from the hip socket, your foot and leg should be pointing away (the 3rd picture in the series). Hold 30 seconds and sit up.
If you are flexible you may need to put your heel up on something like a footstool or on the PILATES MiniMAX to increase the stretch (the last two pictures in the series demonstrate the start and stretch position).