The most famous stretch for tight hamstrings on the Pilates reformer is called “Feet in Straps”. This is a very pleasurable stretch and exercise that involves putting your feet through the loop handles of the reformer ropes and letting the resistance of the tight ropes pull and stretch your hamstrings as you maintain your legs straight up at a 90 degree angle.
The key to making this an effective stretch for hamstrings is in flexing your feet during the stretch. The flexing position emphasizes pressing your heels towards the ceiling and this activates the hamstrings in the back of the legs. While you are stretching in this position make sure to press your sacrum bone against the flat surface of the reformer thus securing the optimum straight leg position.
It is common when first starting this stretch to point the toes towards the ceiling and settle into the position. When you become comfortable flex the feet by pressing the heels towards the ceiling as we have discussed. You may alternate between pointed toes to lessen the stretch and flexed feet to intensify it.