Respuesta :
It is a gerund. If we added the preposition 'by' like, 'by sprinting the gazelle outran...', we'd know better that prepositions, the case with 'by' for instance, went with gerunds.
Sprinting, the gazelle outran the three lionesses.
Verbal: Sprinting
Type: Participle
Function: Adjective
I can inform you with confidence that this is 100% accurate.