Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 3

Sanskrit:

अरत्नी द्वे अरत्निभ्यां जानुभ्यां चैव जानुनी । शिर: शीर्ष्णोरसोरस्तावन्योन्यमभिजघ्नतु: ॥ ३ ॥

ITRANS:

aratnī dve aratnibhyāṁjānubhyāṁ caiva jānunīśiraḥ śīrṣṇorasoras tāvanyonyam abhijaghnatuḥ

Translation:

They each struck fists against fists, knees against knees, head against head and chest against chest.

Purport:

The word aratni in this verse may indicate the elbow as well as the fist. Thus blows were perhaps also struck with the elbow, a technique seen today in various martial arts.