I know one I like for weighted decline sit ups, if your gym has a smith machine and a movable decline sit up bench. Put the decline bench under the smith machine and put weight on the smith bar and hold the bar with your arms out stretched through the whole sit up. I do bar+40x25, bar+50x20, and bar+60x15. More weight less reps seems to be much more effective for me anyways. It will force your abs to stay contracted too where the bar is guided. As far as my reasoning for for the + sets... Not really sure so it's probably garbage. But it works for me. Every week or two I keep being able to use heavier weight, replacing the previous 25 set with the previous 20 set and going from there, and ad the increments to the next 2 sets. Damn that's a lot. Hope that made some sense. Pretty much (X)x25, (X+10)x20, (X+20)x15, and (X) will keep bumping up the more you do them. The weight goes up the reps stay the same.

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