Is there an optimum way to pick large-ish dogs up? I'm walking an elderly lab for a few days and he has trouble getting up stairs, so I may need to lift him myself.
Yes! I have three different ways that I find work well.
The easiest and safest way to pick up a large dog is the same way you would pick up a goat. One arm around the chest and the other around the back end. I find putting my dominant hand/strongest arm around the back end works best as some dogs will lean their weight back and it puts a little less stress on my body to account for that. Most dogs seem to find this way relatively comfortable and supportive enough for being carried up stairs and to and from cars.
Second method is much the same but for the arm around the chest I instead stick it between the front legs and let my hand rest against the stomach/armpit of the dog. This gives me a little bit more control of the front of the dog. This one helps stabilize the more wiggly ones and I can grab the dog's elbow to keep him from kicking and pawing at me if need be. This one is also good for the dogs that let their weight tip back and forth as you walk as you've got a bit more arm under them for them to lean on.
Third way is just hooking one arm under the groin and the other arm under the chest. This one gives me the best leverage for lift but it does place some excess pressure on the organs so I try to use it mostly for quick lifts and for the 100-150lbs dogs. It won't damage them but it can be a bit uncomfortable for the dog.
There are a few other safer/more comfortable options but those typically require a bit of training and time so these three are the methods I use when I just need to get the job done and move on.
I obviously don't know how well you know this dog or if he's used to being lifted but I will add in my be careful lifting a strange dog warning. Big dogs especially may not be used to being lifted and having someone suddenly loom over them and then put their hands in strange places can be threatening. I usually test out a dog I don't know about by petting the areas my arms and hands will be then adding slight pressure and then positioning myself as if I were going to lift them, adding a bit of pressure that way; praising them the whole time and stopping for treats if necessary. Basically testing for any negative reactions before I actually lift and get myself in a position that might get me or the dog hurt.
If the dog seems super nervous and you decide lifting isn't a good idea you can put a towel around the dog's waist to use as a sling to help them walk/jump on their own.
Hopefully that helps. I'll try and add a few pictures tomorrow with my Lab mix. He's a big 75lbs guy so he typically makes a good example when we go over lifting methods in our group classes.