: The concept that tensing one muscle (like your grip or glutes) sends a signal to surrounding muscles to contract harder. The "Phased" Crunch
Frequently cited by reviewers as one of the most challenging and effective strength exercises ever devised for the midsection.
: The concept that tensing one muscle (like your grip or glutes) sends a signal to surrounding muscles to contract harder. The "Phased" Crunch
Frequently cited by reviewers as one of the most challenging and effective strength exercises ever devised for the midsection.
