I am really wondering, have you heard anyone ever use the word sprowl?
To be honest, I’ve never heard anyone using that dialect word. A lot of Anglo-Cornish dialect is rarely heard these days. Most of the books available online were compiled in the 19th century or earlier, therefore a lot of the words and phrases are archaic. The word, variously sproll/sprawl/sprowl means strength or energy. I’m not sure what the derivation is since the Cornish (Kernewek) words are nerth, nell or krevder.