1. Institute of Sport Science, Italian National Olympic Committee, Rome, Italy
2. Department of Physical Medicine and Rehabilitation, University of Rome “La Sapienza,” Rome, Italy
3. Department of Orthopaedic Surgery, University of California, San Francisco
4. Department of Biochemical Sciences “A. Rossi Fanelli,” University of Rome “La Sapienza,” Rome, Italy
5. Department of Trauma and Orthopaedic Surgery, Keele University School of Medicine, Stoke on Trent, England;