I know people who pin crosses to their undershirts to avoid possible tangles/discomfort.
I've been yelled at for not wearing a cross, for having a cross visible, for having a cross not visible, and anything else in-between, including that medalians aren't replacements for crosses, & nither are "Lord have Mercy" rings. It all comes down to tradition I guess. The only comment I've ever gotten about the cross I've worn for the past 3 years (unfortunately I lost it a few weeks ago, am now looking for one to replace it) is "cool cross."
As far as sports go... perhaps the early saints were against Olympics & other competitive sporting events because they were usually played in the nude. I know the original Olympics were at least.
From my life experience, I want to draw a few examples of how modern clergy might look at it...
My parents have a photo of Fr. Seraphim Slabatskoy (writer of "Law of God") playing baseball (he was at bat) with the campers of HOPP (ROCOR youth camp) back in the '60s.
I myself have played soccor on a field in Jordanville with monks/clergy cheering. I've also played football & soccor with clergy also playing (usually at parties where there are bishops sitting inside).
A hieromonk from Jordanville told us a story about the current Archbishop of Australia (ROCOR) playing soccor while still in seminary. He shouted to a team-mate "Adesnuyu, adesnuyu!!!" ("To the right! To the right!" in Church Slavonic) His team-mate yelled back "Nyet! Oshyii, Oshyii!!!" ("To the left! To the left!" in Church Slavonic)