Does light training strengthen stems?

Every once and a while I'll just keep one light on for about a half hour in the morning to straigthen up whatever side is bending, not all day.
Does this actually help to strengthen the stem? I figured it wouldnt cause any stretching bc I have two lights on it 99% of the time
(No yellow on the plant, just my leds)

That actually has no bearing on strengthening the stem structure of your plant. In fact only using half your lights on one side of the plant will increase the stretch And weaken your stem structure. Think of the lights you use on your plants like a gas peddle in a car. Using half the throttle instead of full throttle will make your car go slower. Light is essensually fuel for your plants motor (so to speak). If you want to fix the lean on your plant just rotate the plant itself but always keep all your lights on.