incredulous

The quest to build ever more proficient athletes keeps hitting unexpected snags, and perhaps nowhere is this more vivid than in Major League Baseball. Several top players have been hampered by a hip ailment that was unheard of in the sport a decade ago.

Knee injuries to countless recreational and professional athletes in recent years made anterior cruciate ligament a household phrase and compelled trainers to emphasize building leg strength. Sports medicine experts now say that approach, while mitigating knee injuries, may be making hips vulnerable.

Hip Injuries Bringing More Athletes to Their Knees – NYTimes.com.