I can't understand the lyrics, but I can tell you what I do know!
The song is called
Ӈэдалёрти ныхыдырма (ŋedaljorti nixidirma) and is sung by
Гавриил Лагей (Gavriil Lagei). The Russian description for this song in the Youtube link (Гонки на оленьих упряжках) means "racing on a reindeer sled".
The word
ӈэдалёрти in the title comes from the verb
ӈэдалёсь (ŋedaljos'; "to drive on the road or path") and presumably refers to reindeer here. The word
ныхыдырма in the title comes from the verb
ныхыдырць (nixidirts’; "to compete in strength") and refers to a competition of strength typically taking place during holiday celebrations. It can refer to the type of competition you see in the first photo below where two people sit toe-to-toe and pull a stick in opposite directions, but based on the other information about driving (ӈэдалёрти) and the Russian description involving a race, here it most likely refers to testing the strength of the reindeer and their drivers in a competitive race with sleds, as shown in the second and third photos (a common activity during Reindeer Herders' Day in the spring and other celebrations). This is also shown in some of the photos that accompany the video.
So I presume this is the topic of the song but as for the actual lyrics, unfortunately I really don't know.