The key exercise for treating proximal hamstring tendinopathy is an eccentric bridge. As you start this type of exercise you should have your feet on the ground with your knees flexed to about ninety degrees. As you get more confident extend you knees so your leg forms a longer lever. As you make more progress you may place your feet on a chair or a swiss ball. It is important to remember that the key component is the lowering phase of the exercise.
Lie flat on your back with your knees flexed to approximately 90° and your feet flat on the ground
Engage your core muscles
Lift your low back and buttocks off the ground - so you become supported on your shoulders and feet
Lift the normal leg off the ground (so you are supported by your shoulders and the painful leg only)
Slowly lower your buttocks back to the ground over a 3 second count
Remember these exercises are supposed to be uncomfortable.
You should ideally aim for more than 90 repetitions a day. Start slowly and build up to this number.
You do not have to do all of the exercises in one sitting. It is more manageable to do a number of smaller sets over the course of a day.