Jack Knife sit up for core and abs - BBF 90 Day Fitness Challenge Instruction Video #13

http://ift.tt/19sX5Yt Jack Knife sit up for core and abs - BBF 90 Day Fitness Challenge Instruction Video #13. Please visit our site for more videos, freebies, expert fitness tips and instruction: http://ift.tt/XNfCEO Areas covered in this video: - Jack Knife Sit Up - Jack Knife exercise - core exercises - best core exercises - core strengthening exercises - Ballistic Body Fitness - Personal Trainer Burbank - core stability exercises - abs workout - why do core exercises - core strengthening exercises at home Please visit our site for more videos lots of freebies and expert fitness tips and instruction: http://ift.tt/XNfCEO Share this video: http://ift.tt/1iQJURI Find us on Yelp: http://ift.tt/1bOCRGP... Like us on Facebook: http://ift.tt/1dKhTXz...