<p>At Arsenal, the club where he won the FA Cup three times, Per Mertesacker was affectionately called the "Big Friendly German." Standing at 6ft 6in, he was the defender who took fitness so seriously that he invested ten per-cent of his annual salary on personal therapists. His endurance would help him in a decade- long career with the German national team which culminated in him lifting the World Cup in 2014. In his autobiography, Mertesacker r...