The National Strength and Conditioning Association (NSCA) is the world’s leading organization in the field of sport conditioning. Drawing on the resources and expertise of the most recognized professionals in strength training and conditioning, sport science, performance research, education, and sports medicine, the NSCA is the world’s trusted source of knowledge and training guidelines for coaches and athletes. The NSCA provides the crucial link between the lab and the field. ABOUT THE EDITOR Ian Jeffreys has established himself as one of the most respected strength and conditioning coaches in the UK. He has been the strength and conditioning coach for the Welsh Schools national rugby team and has worked with athletes, clubs, and sport organizations, from junior level to professional level, around the world. Ian is currently a reader in strength and conditioning at the University of South Wales, and also is the Proprietor of All-Pro Performance, a performance enhancement company based in Brecon Wales. He has been a member of the National Strength and Conditioning Association (NSCA) since 1989. He is a certified strength and conditioning specialist (CSCS) and certified personal trainer (NSCA-CPT) with the NSCA, and he has been recertified with distinction (*D) in both categories. He is also a registered strength and conditioning coach – recertified with distinction. Ian currently sits on the NSCA High School Executive Committee and was the NSCA’s High School Professional of the Year in 2006, the first time the award was presented to a coach working outside the United States, and was made a fellow of the NSCA in 2009. Ian is on the British Olympic Association register of strength and conditioning professionals. He is a director of the United Kingdom Strength and Conditioning Association, where he is an accredited strength and conditioning coach (ASCC) and an assessor for the organization. He is also a lead tutor for the UKSCA education workshops. Ian has authored numerous strength and conditioning articles that have been featured in leading international journals. He is the editor of the UKSCA journal Professional Strength and Conditioning and is on the editorial board for the NSCA’s Strength and Conditioning Journal and the Journal of Australian Strength and Conditioning. Ian has authored three books and the warm-up and stretching chapter for the third edition of Essentials of Strength Training and Conditioning. Ian is a sought-after presenter and has given keynote presentations and hosted high-performance workshops at major conferences around the world. His specialty is speed and agility development.