Q:

Does this technique that deals with syllable meters have a name?

On the poem extract below I noticed the following technique and it sounded really familiar, reminding me of punk rock songs and some strong man speeches (I know this is super vague, if I remember any examples I'll link them in the comments). This technique consists of a metric progression of long verses to short verses culminating with a one or two syllable verse, this happens from verses 1 to 5 below, then this is followed by same metric length verses with Anaphoras, in this case it's an anaphora with "the". Does anyone know if this has a name?

1 Pretty women wonder where my secret lies.
2 I’m not cute or built to suit a fashion model’s size   
3 But when I start to tell them,
4 They think I’m telling lies.
5 I say,
6 It’s in the reach of my arms,
7 The span of my hips,   
8 The stride of my step,
  -Phenomenal Woman, by: Maya Angelou 

A:

There is no single descriptor for what you're asking. Instead, writers might indicate repetition of short lines that create a turn or pivot in the stanza.
The most prominent pattern is repetition (source) at the level of utterance:

"I say" performing a turn or pivot or contrast in each stanza from what others say and what the speaker says
"I’m a woman / Phenomenally. / Phenomenal woman, / That’s me." ending the self-directed speech and the stanza.

As for the changes in line length, especially with "I say," one could describe the break of pattern (turn/pivot/contrast) as a short line (if the other lines are normally longer) or a long line (if the other lines are usually short). This vocabulary filters into descriptions of line length:

The short, irregular lines of John Burnside's 'De Humanis Corporis Fabrica' mirror the slow accumulation of various bodily details in the poem. (https://www.poetryarchive.org/glossary/line)
Long lines are oceanic. They wash over you like waves, one after another, each of them full of shells and sand and fish and surfboards, sometimes pieces of wrecks and the bodies of sailors. The long line is more conclusive and inclusive than the partial, subdivided short line. If short lines are like quick pants, long lines resemble great, deep breathes. (https://poets.org/text/whitmans-long-lines)

And an example from the Victoria and Albert Museum describing a similarly-structured poem, "Things Men Have Made" by D.H. Lawrence:

The most obvious device here is the repetition, with variation: 'men have made', 'men who made'. These phrases occur at the beginning and end of the poem, with a single syllable before the first occurrence and after the second. They balance each other, emphasising a balance between the first two lines and the last two, between the first sentence or proposition of Lawrence's statement and the second, which echoes it and develops it further. The whole poem pivots around the very short line in the middle, 'for long years'.

