Runner Looking to Gain Weight

Hey everybody, brand new to this site. Saw my brother looking at it before though. I’m a runner and the spring outdoor season begins in a few weeks.
I am a middle distance sprinter (400m and 800m). I have a nagging knee injury (patella tendinitis). I want to gain upper body strength to help burn lactic acid and maybe some pre-season leg work so I can work on speed?

I am 6’4 and 180ish pounds

Can someone help me with a workout routine?

As a middle distance runner you have to weight up the benefits of strength gain vs weight gain. Also are aesthetics more important than performance? If you want to go down the path of being a strong runner - opposed to being a light and fluent runner, who has the benefits of being ripped at the same time, then i would suggest a programme that consists of reps in the 3-6 range and may be some sets in the 15-30 range to help with the “lactic acid training”. This of course depends on your current strength levels. Jonathon Edwards UK triple jumper had a weight programme that consisted of 8 sets of 1 rep. So he had maximum strength gains with little hypertrophy.
Also remember that the majority of Kenyan runners don’t do any weight training as such, they just do sets of hill sprints say 8 times 80 meters.
Also how does upper body strength burn lactic acid?
And there is debate over whether it is lactic acid that actually causes the crazy burn at the end of the 400 meters.