Hypermobility Syndrome is where the joints are more flexible than those of Mr or Mrs Blogs. The reason is there is proportionally more elastin to collagen in the connective tissues of people with hypermobility. The extent of this differs from person to person.
In yoga we would have to be vigilant not to over extend any vulnerable joints. The main joints to watch out for would be the knees, Elbows, wrists, low back and pelvis. When we talk about movement in a joint we refer to flexion and extension. Flexion of the elbow would bring the hand to the mouth, and extension would be to straighten the arm. We would watch for over extension especially in the downward facing dog position.
In the knees we would refer to flexion when we bend our knees, and extension when we straighten the leg. Note that the knee can normally hyper extend by about 5 degrees. Again we would be careful in people who are Hypermobile, not to hyper extend the knee while weight bearing. Positions to watch would be Trikonasana (Triangle Pose), and Wide legged forward bend, and similar positions.
The sacro-iliac joints are a very common area to cause problems in those that are hypermobile. Note it is possible for this problem to have been made worse through pregnancy, and child birth. With this issue we would be looking to strengthen the area rather than to stretch. This would put the emphasis on core stability, and strength in the hips, and legs. For example in the wide legged forward bend (If safe to do so for you personally) we would advise that it would be better to just come down by 90 degrees so your upper body was level with the floor. You can then hold this position while holding the core. I would also advise being careful with all forward bends to stretch the hamstrings. Instead you could do one leg at a time using a strap, while keeping the other leg bent at the knee.
Wrists can also be sore in positions such as downward facing dog. You could use a thicker mat, or fold over your present mat to double its thickness.
It is really important for anyone in a Yoga class that you listen to the body, and only do what feels comfortable to you in that moment. What we can do will change from day to day, moment to moment. If we don't listen to the body we will inevitably hurt ourselves. If you have any concerns about taking part in a class please consult your Doctor, or other Healthcare professional. Make sure your Yoga Teacher is aware of any concerns or problems you may have before the class.