Tough mudder is hard. I found it harder than a half marathon. Anyone with a decent level of fitness could finish. But I managed to maintain a decent pace and do it in just over 2 and a half hours. Has anyone ran a marathon to compare? And anyone who hasn't done either and has watched videos should shut up and congratulate anyone who has. These are proper ordeals for your body and anyone who's come out on the good end has done well.