To reveal key facts about chronic back pain, osteoarthritis and acute pain, and give insight into how these debilitating conditions can be treated, these medical mavericks used each other as human guinea pigs in fun and often painful experiments.
Greg donned a pain-inducing ‘osteoarthritis suit’ and revealed the horrors of performing everyday tasks in it, while Jack entered the fight cage, going head-on with a man whose sole intent was to inflict acute pain on Jack’s legs.
So, when the doctors said it was going to hurt them more than it would hurt you, this time they really meant it.
Along the way Jack and Greg revealed useful facts and helpful approaches to treatment.
If you missed the original broadcast you can view it on BBC iPlayer