http://arthritis-research.com/content/9/2/R34/comments The latest comments on the article 'Relationship between physical activity and stiff or painful joints in mid-aged women and older women: a 3-year prospective study' 2007-04-11T16:42:51Z http://arthritis-research.com/content/9/2/R34/comments#272538 <p>Unless I misunderstand the structure of this research, there is no random assignment of participants to active vs inactive groups.</p><p>Therefore, it is unjustified to conclude that exercise is beneficial. It may simply be that women with arthritis pain are less active, BECAUSE they are in pain.</p> Gershom Lundberg 2007-04-11T16:42:51Z http://arthritis-research.com/content/9/2/R34 Heesch et al. Arthritis Research & Therapy 9 R34 Thu Mar 29 00:00:00 BST 2007