Russ Cook just can't seem to leave injuries and illness behind. After food poisoning in Cameroon, he's had persistent back pain in Nigeria. More worryingly, he has blood in his urine again, a problem he had early in his expedition.

Cook reduced his daily mileage to help his body recover, first to 30 miles per day, then 25, before having to take a few days off to get his back looked at. "Back problem turned into probably the biggest injury I’ve had on the mission so far," Cook wrote.

But the scans showed no bone damage and Cook decided to take some strong painkillers and continue. He launched back into 37-mile days and was pleased to see some improvement in how he felt. "Was expecting to have to nail bollocks to the wall again today but noticed some slight improvements which has done wonders for the mental. Confident I double down on this recovery over the next few days and back on top form in no time," he wrote in his latest update.