Both spinal mobility and flexibility of the hamstring muscles were increased by the end of the study. Again, unfortunately, this was not a randomized controlled trial or a treatment comparison group. In a muscular endurance study yoga was compared to an inactive control group [31]. Following 18 sessions (three times per week for 1 h per session) muscular endurance was measured in the upper limbs by push-ups and in the abdomen by sit ups. The yoga group, as would be expected, showed greater improvement in both upper limb and abdominal muscle endurance