
I'd concentrate more on playing games indoors or in the garden, use the lead walks as training exercises, sits, heeling, waits, stays that kind of thing.
A few games you can play.
"Springer's Find The Lady" using upturned plant or yoghurt pot with a ball or treat under one of them. Remember he only gets the treat if he guesses correctly.
Using dried food...... Hide his dinner (or a portion of it) around the house/room - another fun "Find it" game!
Save all your small boxes such as toilet roll tubes, toothpaste boxes etc and put a biscuit or two in them so your dog can rip the box open and earn himself a treat and expel extra energy.
You can then go on to hide the box and teach your dog a Seek command so he then has to hunt to find the box before he gets his reward and use up even more energy.
Big box (crisp box size - but obviously no staples or tape) - 1 or 2 smelly treats (we use pigs tails) and lots of scrunched up newspaper. How well you hide the treat is up to you and your dog's ability to "find" before getting bored. Turn the box upside down so that the open bit is covered, tell him "It's yours" and sit back and watch the fun! You can also layer the boxes with a treat in each layer using different sized boxes and paper.
Of course, if you also teach your dog "pick it up" then they will "help" you clear up the horrendous debris too!
Treat balls are another excellent idea, the one shaped like 3 balls stuck together so it doesn't roll easily, there is also nothing on it for them to get caught and hurt themselves. Buster cubes are another good activity toy for dispensing there dried kibble, keeps them busy for hours, and even when empty, they can't resist going up to it every so often and giving it a belt, 'just in case