I don’t understand why the left hamstring is lengthened and the Straight Leg Raise test is limited on the left. Doesn’t the lengthened hamstring give more leverage to the hip flexors?
The left hamstring is lengthened because the left ischial seat is elevated due to forward rotation of the left innominate. For example, you could rotate both innominates forward if you were attempting to bend over and touch your toes. When the left innominate rotates forward without the right and only the left Ischial seat is raised (like the toe-touch example) the hamstring on the left is lengthened but the right is not. This position is present in those individuals with a dominant Left AIC pattern. Now imagine this person is lying on their back and you compare the right straight leg raise to the left. On the right (the side in which the innominate is NOT forwardly rotated) the straight leg raise should be greater because the right ischial seat is not elevated and the hamstring has not been lengthened already. On the left where the hamstring is already lengthened due to the raised ischial seat the straight leg raise would be less. If it is symmetrical or greater on the left then you have real trouble because now the individual has over-stretched an already lengthened left hamstring.