Took a plunge

• Did a gainer, say
• Engaged in some flopping
• Made a splash?
• Declined sharply
• Did a full gainer
• Jumped into a swimming pool, in a way
• Took the plunge
• Did a jackknife, say

Wiktionary Word definitions in Wiktionary
vb. 1 (en-past of: dive ) (gloss: scuba diving) 2 (past participle of dive English) (gloss: jump head-first)

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Dive \Dive\, v. i. [imp. & p. p. Dived , colloq. Dove , a relic of the AS. strong forms de['a]f, dofen; p. pr. & vb. n. Diving .] [OE. diven, duven, AS. d?fan to sink, v. t., fr. d?fan, v. i.; akin to Icel. d?fa, G. taufen, E. dip, deep, and perh. ...