For swimming
For swimming, dead bug rates higher on our research criteria: more injury protection.
Both are good choices that build different things for swimming, so a plan can use both.
The research score comes from these, scored by hand from the studies. Lifter scores appear once an exercise has 10 ratings. How scores work
For your abs, hanging leg raise rates well ahead on our research criteria: more stretch, easier to progress. Dead bug is easier on the joints.
For swimming, dead bug rates higher on our research criteria: more injury protection. Both are good choices that build different things for swimming, so a plan can use both.
Dead bug is easier: it’s easy to learn, while hanging leg raise takes some practice.
Dead bug needs no equipment, so you can do it anywhere. Hanging leg raise needs a pull-up bar, so a home gym covers it.
Dead bug: it rates Good for injury protection in our research rubric, against Fair for hanging leg raise.