Lisa Herrington, co-owner of Fit House in Davis and personal trainer, shares this at-home exercise. Here’s how you do jack knives: ...
• Start lying on your back with your arms straight, holding the stability ball above your head and your legs straight. • Lift your arms and legs at the same time while lifting the stability ball.
Some results have been hidden because they may be inaccessible to you
Show inaccessible results