Stress 'makes players vulnerable to injury'

German midfielder Jan Kirchhoff's hamstring injury has added to Sunderland's list of key absenteesStress could be contributing to Sunderland's growing injury list, says midfielder Steven Pienaar.

The Black Cats are bottom of the Premier League, without a win all season and with just two points from a possible 24 available.

David Moyes' side have been hampered in their bid to end that run by injuries to Lee Cattermole, Jan Kirchhoff, Adnan Januzaj and Fabio Borini.

Pienaar told BBC Newcastle: "If stress levels are high, you're vulnerable."

The South African added: "When results aren't going your way, the tension and the stress gets to your body and though I'm not a doctor, you're more likely to…