A
sound ab workout should enhance the ability of the abs to both move and
stabilize during all core dependent functions. With regard to that functional
role, an ideal abdominal workout aims to involve exercises that sufficiently engage
and challenge the abdominals while a large portion of the body is active/under
tension. Such ab integration with the body, however, might still fail to
include dormant muscles critical to a healthy core. As such, the ideal abdominal
workout should include dormant engagement as well as integrated strengthening.
Dormant muscle engagement
Engaging dormant muscles means
"waking up" muscles that aren't participating as they should during
life and/or conventional exercise. This lack of participation is often
implicated in back pain and impaired performance. Some muscles often believed
to be dormant include the multidifidus muscles around the spine and
pubococcigeus muscles of the abdominal floor.
Because these muscles aren't believed to be engaged properly by "conventional exercise", different techniques and modalities are employed to engage them. Among the techniques are muscle spindle activation and/or irradiation/kinetic-chain-contribution. Such techniques are often implemented using modalities ranging from Swiss balls to slide-boards.
Engagement techniques
Dormant muscles are believed to be disengaged or lazy when they're needed and resistant to voluntary engagement. The facilitation of certain neuromuscular tendencies, however, might enhance the engagement of dormant muscles. Among these tendencies are the muscle spindle response to rapid stretch and the irradiation/surrounding-kinetic-chain contribution resultant of voluntary contraction of synergistic muscles.
Facilitating the muscle spindle response
Muscle spindles are structures within skeletal muscles that will contract/amplify-contraction of muscle if it's rapidly stretched. This contraction response is called a "stretch-reflex" and is what the doctor is checking for when tapping your knee hoping for an involuntary kick. Like the involuntary kick that occurs from the rapid, but short, stretch induced by the knee tap, short/rapid movements at/around the spine might facilitate involuntary engagement of the dormant muscles there.
Ways to facilitate such short, rapid, and dormant-engaging movements around the spine involve increasing the challenge of the core to balance/stabilize the spine. Such increased challenge can be realized by demanding the support of some/all of the bodyweight on unstable surfaces/support-bases. Implements like Swiss-balls and balance-boards and/or narrowing the base of support during various poses and exercises can all result in trembling (rapid movement) around the core.
Some example exercises and progressions that will challenge core-balance/stability are plank variations. A regular plank and/or side-plank, if not challenging/trembling enough, can be challenged by placing the elbows/feet on an unstable surface such as a balance-board/swiss-ball. For many, the ball/balance-board will present rapid/trembling rotational stress on the core that, I find, "lights my deep-core up" in ways no other ab workout can. Additionally, removing the support of the arms/legs can also be utilitzed with/without the ball/balance-board.
Facilitating irradiation and kinetic-chain contribution
Irradiation is a tendency of the engagement of given muscles to be amplified by the engagement of other muscles. Kinetic chain contribution is a term I use to describe initiating multi-joint tension/movement in the efforts to engage certain muscles along that chain,
Most of us utilize irradiation when doing anything strenuous exampled most obviously by the intense contraction of facial muscles during such activity(side note: the relaxed faces and postures advocated in stretch/yoga-classes are meant to reduce irradiation so the muscles can more readily relax).
Kinetic chain contribution is seen pretty commonly with leg raises; which is the initiation of leg movement to challenge pelvic stability that in-turn demands ab contraction to keep the pelvis anchored. It's important to note for our purposes, however, that the closer the muscles the more intense the irradiation/kinetic chain engagement.
Both irradiation and kinetic-chain engagement can be facilitated for the purpose of dormant muscle engagement by simply intensely contracting muscles as close as possible to those dormant. For some, traditional exercises are "close-enough" to facilitate irradiation/kinetic-chain engagement. But for most of us spoiled by modern-life, however, unconventional exercise techniques meant to get even closer to the dormant muscles might be warranted.
An irradiation technique popularized
by Pilates practitioners seems to work quite well at delivering what many feel
is abdominal floor engagement. That technique is the simple engagement of
the hip adductors/inner-thighs during ab workouts. Recruiting the hip
adductors in an ab workout can be as simple as holding a weight/medicine-ball
between the legs/thighs during leg raises.
Conclusion
To maximize your efforts in your ab workout, help ensure that dormant muscles
aren't hindering the progression of your core strength. Integrating a set
or two of dormant-integration-techniques might result in a feeling of greater
durability around the spine and amplified tension in strength-focused core
movements. Such exercises might also give you the excuse to utilize fun
equipment and body-positions.