Oh, okay. So in that case, yes I agree - keep the forward momentum going. Encourage BEFORE he starts to balk, even try to increase his speed well before if it's always at the same place.
Sometimes my horse will decide she doesn't like where we are headed. I will go back and forth over the same area as many times as it takes for her to finally walk properly where I want her to go. Walk her forward, turn around, walk almost to where we came from, turn around, walk back the other way a bit further, then back the other way not quite as far again -- repeat ad nauseum. By fits and starts, we end up walking BACK to where she didn't want to go to in the first place. I don't let her stop walking except at the spot that she didn't want to be/go to.
If she doesn't want to stand somewhere, I keep moving her back to the location I asked her to stand at - if she backs, I move her forward; if she goes forward, I back her. I try to pick an object as a benchmark so I don't get out of place myself. Most times I can stop her movement before she picks up her feet, which is the best. Once she is still, I let her relax and think about it.
On those days, I don't try to accomplish much else.