Skip the crunch If your aim is to strengthen your core.
The crunch motion puts you in spinal flexion, and reinforces the bad slouching posture that we fight against all day while sitting. Furthermore, it emphasizes the incorrect notion of spot reduction.
Remember, no amount of crunches will blast away belly fat. On the contrary, focus on firming your body from head to toe.
Plank are the key to a strong core with focus on extension of the rectus abdominus known as the ‘six-pack’ muscle.
To perform a plank: Prop yourself up into a plank with your hips and shoulders at the same level — on forearms or full hand — and hold for 10 seconds. Take a 5-second break, and then repeat. After 30 seconds of this, most people are cooked. Going for 5 or 6 rounds is really hard.
Whilst the plank and crunch both work the abs, they engage the midsection differently in many ways.
The plank requires an isometric contraction or static holding of the spine for the duration of the exercise. All while, the crunch requires spinal flexion. It’s the comparison between an isometric move versus a dynamic one. They do have some similarities with clear differences in the primary and secondary focus.
Crunch primarily targets rectus abdominis, the frontal six-pack ab muscles, and obliques, the two sides of your torso. Put simply, it effectively tones your front abs and shreds the waistline. It’s also the very reason crunch is the front liner for any six-pack abs workouts.
Plank too engages the rectus abdominals and obliques, but it also activates the shoulders, glutes, and hamstrings. There is an engagement of muscles throughout the erector spine with a static hold.
Simply put, plank exercise engages all your core muscles and more. Exercises that stimulate the deltoids (shoulders) and glutes activate the abdominal and lumbar muscles in greater intensity. It’s equivalent to a scientific testament on how well planks work the abs and core.
Why is Plank Better than Crunch?
Does it all mean the plank is the winner? Is it really a better ab workout than the crunches?
While planks are not without cons and crunches have many pros too, planks do come on top in many areas.
To start, research indicates that forearm planks trigger twice the average muscle activation in the rectus abdominus and external obliques than a traditional crunch.
This also explains why more core training workouts nowadays include exercises that work the hips and shoulders.
Another reason plank trumps crunch is that planks are gentler on your back than crunches. For those with back pain and weak back, flexing of the back in crunch movements tends to be hazardous. It’s simply too easy to strain and pull the back when the exercise is not performed correctly.
Lastly, unlike dynamic moves, plank’s isometric hold requires constant muscle activation during the exercise. Whether it’s for 30 seconds or a minute, the muscles in your abs and core need to stay engaged throughout. And that’s a unique advantage of performing the planks.
But holding a plank for longer is not the best option for a progression according to Dr Wayne Westcott PhD of Quincy College, Quincy, MA. He states that to build muscle strength, muscle fatigue is needed within the anaerobic energy system, which takes around 60-90 seconds.
Note: Keep your planks under 90 seconds at most. Instead, progress through plank variations from easy to hard.