Need help with translating a sentence

Question

The sentence is:

俯伏{うつぶ}しに延｛の｝び切｛き｝った身体｛からだ｝を縮｛ちぢ｝めて一寸{ちょっと}腰｛こし｝の所｛ところ｝を高｛たか｝くした。

For context, this is a short story by Naoya Shiga, the name is 「十一月三日午後の事」. Right before this sentence, the subject of this sentence trips and falls face down and is very exhausted. He has someone trying to help him up, and he is trying to get up as well.

I know the meanings of the words individually or the probable meaning for those that have more than one, however, I'm unable to picture what the author is trying to say.

Later on, the author describes this action as

芝居{しばい}で殺｛ころ｝された奴｛やつ｝が俯伏｛うつぶ｝しになった場合｛ばあい｝よくそう云｛い｝う動作｛どうさ｝をする。

I took this to mean "In a play, when the guy who gets killed is lying face down, he often does this action."

However, I still can't put together what the author means.

Answer 1

ちょっと腰のところを高くする ("to elevate one's hip/pelvis a bit") from the うつ伏しにのびきった ("flat prone") position should look like this:

In a movie cut scene, we often see a dying person who doesn't have enough energy to stand or sit does this.