Firewall
The essence of training derives from consciously strengthening the immune system, under pressure.
See also: https://bartvanbroekhoven.com/en-US/component/search/?searchword=bandura&searchphrase=all&Itemid=298
See also: https://bartvanbroekhoven.com/en-US/component/search/?searchword=immune&searchphrase=all&Itemid=298
Sharp
A sharp knife can safe a runner's life.
Despite the naked, unprotected exposure to objects that have the potential to injure the barefooted runner, wounds are exceptionally rare though. In the domestic environment injuries occur more often — small pieces of glass are the main cause of cuts. Thorns are the most common perpetrators of barefoot obstruction in the outside world. Their smallness is inversely proportional to the cause of hinderance and need to be removed to remain fully mobile and in balance. A sharp knife -- and the abililty and willlingness to use it -- is one of the few basic tools that serve the barefooted runner well.
See also: https://bartvanbroekhoven.com/en-US/component/search/?searchword=thorn&searchphrase=all&Itemid=298