Not condoning the dude's overall fish fighting technique.... just using the vid as a decent demo of how to make a rod bend.

The DIRECTION one makes it bend is even more important, esp when the fish is below you in current. Getting sideways and parallel to a fish in current is obviously the most advantageous position. Stepping down river is advised whenever feasible, but folks should remember to take line as they go! The biggest mistake I see is folks walking downriver too slow and not shortening the leash as they go... they're literally walking the dog down the river.... and making ZERO net gain! And losing precious landing beach with every step! Eventually there comes a point in the battle where one must simply stand his ground.

On river right, the only way to go is to pull LOW and to the RIGHT. As much as is humanly possible... as in 95-99% of the time... the rod should be angled low and right!

When fighting a BIG fish in the current, one of the least appreciated concepts is the mechanics of "ferrying". If you tether any long object in the current it will passively maintain its position in the flow as long as it aligns itself axially with the current ( nose pointed straight upriver at 12:00).

It can also be made to move passively crosscurrent by ferrying. If that long object is somehow pointed off-axis to the flow, even by the tiniest amount (11:55 or 12:05), it will start to ferry cross-current.

In this case, by pulling to the left, one points the fish's nose to its right toward heavier flow, causing it to passively ferry to its right. And when the fish adds extra propulsion with a tail thrust, it's driven that much stronger to its right. This maneuver only encourages the fish to move further out into swifter current.... which only pushes it even further downstream. NOT GOOD if your goal is to gain line.

By pulling to the right, the fish will passively ferry toward the bank... AND when it thrusts its tail, it will actively swim into softer shallower flows, water where one actually can either gain ground MUCH more easily... OR better yet, allow the fish to simply beach itself.

I've used this technique to single-handedly beach dozens of big kings up to 70+ without the aid of a net or an assistant. It works!