Hamstrings, glutes and low back could all be contributing culprits in this situation. However, there are other muscles invovled at the hip joint that could be limiting factors as well. If the adductors are tight or glute medius is weak, along with the limitations of the more major culprits, sitting up with legs straight will be challenging.
I am in agreement with both Julie and Karin in this instance. Explore these areas cautiously. Everyone has different degrees of limitations in these areas so finding which ones are the most active in limiting your client’s ability to sit upright should prove to be an interesting journey.
Harold E. Rose, Jr.
Ab-Sutra Health and Fitness Coaches, LLC
Be Healthy, Be Ageless, Be You.