what's the purpose of straddle up, MN/PE2,

#1.

what's the purpose of straddle up?

what is this workout's target area?

#2.

focus points says 'sit the chest up as high as possible without CAVING IN'

but I don't get why.

well, final goal of this workout is Manna,

so I thought I have to engage my core muscles especially abs,

trying to roll up from the starting point, which means I tried to cave in my upper body as possible as I can

#3. 

I cannot lift my legs as high as the demo video (or I cannot fold my upper and lower body fair enough)

should I just stick to this waiting for my mobility get better?

or do you guys have any tips?

#1 - Developing hip flexor strength & straddle range of motion.

#2 - I think this is to avoid the flexion coming from rounding back, when it should be from hips.

#3 - Stick to the exercise, and work on your pancake flexibility. I found that when starting to focus on improving pancake flexibility the ROM on straddle ups started increasing with better pace.

Also, doing daily active flexibility drills has helped me.

Like in the picture, but don't use any ropes/hands to pull the leg. Instead use your muscles to pull the leg as close to your torso as you can, while still keeping the leg straight. In end position, hold for a couple of seconds.

Later manna positions like middle split holds requires a strong straddle. So for manna you training both "both straddle and pike" with ppt, 2 in both

Hanlim Lee said:

#3. 

 

I cannot lift my legs as high as the demo video (or I cannot fold my upper and lower body fair enough)

 

should I just stick to this waiting for my mobility get better?

 

or do you guys have any tips?

In addition to working on pancake flexibility and simply doing more of MN/PE2, I have found that working on mobility in the squat position and doing barbell back squats have greatly improved my ability to execute the straddle V-up. I already had good mobility with it, but adding the squats gave me a wider and stronger straddle which is much easier to hold without bending my knees. Too bad for me I had already reached mastery before I started doing squats again and discovered this.   At least now regular V-ups are a cakewalk.