Sibusiso Kubheka pushed faster and beyond early Tuesday morning as he shattered the six-hour mark at the 100 kilometer distance in a time trail in Southern Italy in 5:59:20. The Adidas-curated event, “Chasing 100,” used the Nardò Ring track in Lecce, Italy as the stage where Kubheka and four other ultrarunners — Aleksandr Sorokin, Jo …