No, the two are complementary. Horton suggests you incorporate both the butterfly sit-up and the original movement in your routine and use it as a way to keep your training varied.
“A butterfly sit-up is going to be a little less hip flexor, a little more groin, but I would use it as a variation,” says Horton, who programs both into workouts for his high-performance clients.
“Typically I’ll have one or two days a week where our athletes work their core with a bodyweight circuit. It’ll be four or five bodyweight movements and we knock them out back to back at the end of a workout. This is a movement I would add into that.
“Or you could use it as a warm-up exercise. If you’re doing two rounds of six or seven moves to get ready for your workout, this is a great exercise to include for 10 reps. That way, you’ll get both the core and the groin warmed up.”