Hoops

Defence - move your feet more

Again, it's a really old and outdated myth, 'fast movement' doesn't equate to actually improving in lateral or linear speed.

What is more important is increased force production into the floor through the feet, that's where you get the improvement in speed/power. Which is even more important in the development of a young athlete.

Australia is slowly catching up to the rest of the world with sports science in junior sport, still so far behind though...

Just to be clear, the OP is referring to a young kid whose body control and coordination is probably still in early development, the agility ladder can certainly improve these elements and result in better movement of the feet, which I believe was the major topic.

Agility ladders are good for eye/feet coordination, they are also good for improving a kid's endurance/fitness, they can definitely improve footwork, agility and balance, among other things that you can get from them the 'speed' term I used isn't straight line speed.

The speed, or technically speaking, the quickness of movement in your feet and speed with which you can adjust and coordinate your hands, eyes and feet in sort sharp movements can be enhanced using agility ladders.

The end result for a player is highly likely to be an improved defensive capability.

That's the 'speed' I was referring to, not how fast someone can run up the court, which of course is their linear speed, subject to their stride frequency, strength and power.

Replace 'speed' with 'quickness or agility' in my original post and it may make more sense...

Agility ladders do nothing to enhance speed and defensive ability, it's a really old and outdated myth that.

Go and buy an agility ladder and check out this link https://www.youtube.com/watch?v=67XP-AekUoA for some basic drills to help the kid with his overall footwork, balance and speed.

Other advice given, above, is all worth considering...

AKA +1

I always knew them as ‘coojies’ when I had to do them at training. One coach jokingly said that if any foot stayed in contact with the court for more than 5 seconds it would start sticking to the ground, so that I’d never be able to make a quick take-off.

The other thing to consider is whether your son’s body position and the foot his weight is on allows attackers to blow past him quickly. A body position which ‘encourages’ the attacker to go in a particular direction, together with the weight being over the leg furthest from that direction, should make it easier to take that quick first step on defence.

How old is the boy? Coaches are often guilty of assuming players know what they're telling them to do when quite frequently they have no idea.....and that's right up to pro level

Kid of poor coaching to assume the kid knows what he means? Shouldn't he be more descriptive?

If you don't want to butt in, have your son ask the coach for a few YouTube videos of drills he could do in his own time.

Alternatively, if you frame it well, only an absolute monster wouldn't respond well to:

"Hey, thanks for the post-game suggestions for my son. He's really keen to work on it. Do you know of any good drills I can look up on YouTube that help with that sort of thing?"

Basically means he needs to work on sliding his feet laterally quicker.

Too many players try and play defence with their hands and/or bodying them up.

Beat a player to point X by getting there with your feet..once your feet are there you've bet him, your chest is square and he cant go around you.