I was an infantryman. While on light infantry field maneuvers, you would carry your ruck which would have your sleeping bag (all the camping gear you need) and your extra uniforms and food and water. Plus one morter round for the morter guys. On contact you would drop your ruck in a designated area and fight with whats on your body. A combat load of ammo, water, first aid pouch, and your gas mask. You might have some food in a cargo pocket.
And yes, there are still traditional "light infantry" units. 82nd , 101st 10th mountain, 173rd just to name a few. They may be mounted for certain missions like A-stan. But their doctrine hasnt changed.
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