If we look at the same downhill slope now, but we consider what the golf ball is going to be from this position, so as I step up on to the mat here, I want a 10-degree down slope, so aiming in the direction of the target but 10 degrees straight down the hill, now effectively that 10 degrees is taken off and reduced from my club head loft. So as I strike the golf ball my club head would feel about 10 degrees less lofted, forcing it very low, 10 degrees is effectively 2-1/2 golf clubs. So leaning into my left-hand side here and chasing down on the golf ball the ball flight would come out very, very low, because the hill is also pulling me in front of the golf ball the face is generally going to stay open and this ball could cut slightly as well, so I am expecting a low flight that has some cut. And because it’s a low flight I might see that the ball doesn’t actually fly out as far as I was expecting, it lands sooner but it will then roll a long way. So it might go its total distance, in fact it might go further than a 7 iron would do on a flat lie but it certainly won't fly further. So depending on what's in front of me and depending on what I have to carry over, this club could go further than normal but I have got consider what it would roll through, what would it fly over. So if I hit this ball now with this 7 iron its going to come out very low and possibly cutting, and it comes out like a rocket low, 5-10 yards right off my target but never moved more into the 10-15 feet off the floor, certainly a lot lower than I would normally expect from a 7 iron.
Golf Drill Tip: Downhill lie - What the ball does (Video) - by Pete Styles