Question on SLS PE1 Deck Squat & PPT

#1 

I finished 11th week of SLS PE1

but i faced some trouble on this week. 

As I do 5sets of 15reps, I found my tailbone hurts as I pound it as i roll forward.

When I took a shower, I saw skin near tailbone is slightly bruised

and skins peeled off as if I rubbed it with dry tissue.

This must be wrong and I found it on 11th week, damn! 

One more thing. As I stand up from rolling forward, I think muscles near ankle joint  engaged  too much.

I feel the roll is not smoothly continued to the stand up position

 I press my feet hard to supplement lack of momentum of rolling. 

Please tell me what's wrong and how to fix it. 

#2

Many said keep PPT while doing HBP PE1 or SL PE1 scapular shrugs.

meaning that my pelvic should not roll forward making arch at my lower back.

Most of them says squeezing glutes as hard as i can helps me to keep PPT

but I don't get it. As I squeeze my glutes hard at push up position, just the opposite happens.

Can anyone provide Youtube clip or self video ?

Thank you. 

1. Use a padded surface like carpet, a mat of some sort, etc. You can use your arms for additional forward motion if needed. The athlete in the course video uses his arms to help make the roll smoother.

2. Tighten your abs for posterior pelvic tilt. The top portion of your pelvis will tilt backward.

^What Rayne said.

Also keeping good compression (knees pulled to chest ) throughout the roll should make keeping the back round easier, make for a smoother roll, and allow you to use the momentum that you stored from rolling backwards more efficiently to get back to your feet.

Regarding PPT, the glutes do tuck the bottom of the pelvis "under" and are responsible for extending/straightening the hip joint, so squeezing the glutes does help to maintain PPT in Push-ups and sPL progressions and prevent "piking/flexing" the hips.

But, the abdominal muscles also pull the top portion of the pelvis "back" and " flex" the lumbar spine thus resulting in the flattened or curved lower back associated with PPT. So you definitely have to engage the core muscles strongly if you want to achieve a good PPT along with the glutes.

Keegan said:

^What Rayne said.

Also keeping good compression (knees pulled to chest ) throughout the roll should make keeping the back round easier, make for a smoother roll, and allow you to use the momentum that you stored from rolling backwards more efficiently to get back to your feet.

Regarding PPT, the glutes do tuck the bottom of the pelvis "under" and are responsible for extending/straightening the hip joint, so squeezing the glutes does help to maintain PPT in Push-ups and sPL progressions and prevent "piking/flexing" the hips.

But, the abdominal muscles also pull the top portion of the pelvis "back" and " flex" the lumbar spine thus resulting in the flattened or curved lower back associated with PPT. So you definitely have to engage the core muscles strongly if you want to achieve a good PPT along with the glutes.

If squeezing glutes is so important to keep PPT, should I squeeze my glutes when I do FL/PE1 Bent Hollow Body Hold?

I just tried it but I cannot keep contracting glutes lol.... 

I don't, but some people find it helpful. For FL/PE1 and PE2 I just focus on tilting the top of the pelvis back and flexing the lumbar spine. Once the hips extend though, FL/PE3 and beyond flexing the glutes becomes more important and necessary.