We examined ninety-six top-level volleyball players from eight teams
that competed during the 1985 European Championships, and twelve players
were found to have asymptomatic isolated paralysis of the infraspinatus of
the dominant side. Three players were studied with electromyography and
Cybex-II isokinetic dynamometry. The results revealed denervation of the
infraspinatus and approximately a 22 per cent loss of strength of the
affected arm during external rotation. These findings were attributed to
repeated stress due to stretching of the nerve during cocking of the arm
and follow-through when the athlete was serving.