Seated yoga poses usually are taught after one gains proficiency in standing yoga posture. For may people the muscles around the joint including inner groins and buttocks are tight. Restriction in the pelvic region prevents yoga students from sitting upright with ease.  Using yoga props such as yoga blocks, yoga blankets, yoga bolsters, and the wall can provide some stability and ease in seated yoga postures as well.  Regular yoga practice of standing  poses are key to developing the flexibility need to do a seated yoga asana correctly.