I posted a link to an article on squat depth in the Barbell section but it's relevant for those who goblet squat with a kettlebell, too. In fact, this movement is discussed in the article as well.
http://www.strongfirst.com/community/threads/good-article-on-squat-depth.5838
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http://www.strongfirst.com/community/threads/good-article-on-squat-depth.5838
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