If you have pretty restricted hamstrings, you may not be able to keep your butt significant and straighten your legs simultaneously. If that's the scenario, It is Alright to maintain a slight bend in your knees. Your hamstrings will lengthen over time with steady practice of other poses. This sort http://canuseedogfleas95059.timeblog.net/1237631/what-does-dog-pain-killer-injection-mean