Question:

My son has problems with his stride, what can I do

Gaston Schaeffer answer to correcting a faulty stride

Problems with the boots.

Usually problems with boots only comes if the boots are too large and don't fit properly. Boot bought second hand can be made to fit like new ones (unless they are completely broken down) by simply going to the sport shop and putting them into the oven (special oven please don't use the one in your kitchen) and lacing them tightly to the feet of the skater. They will mold and take the shape of the foot.

Blade miss-aligned:
That is another possibility. Blades in hockey skates are simply mounted by machines and riveted into the center (more or less) of the sole. However we do not all have the same alignement and that can cause some problems. That problem can be fixed usually by moving the blade to the inside of the foot. Actually the skater should feel that the blade is between the large toe and the second toe. That is the ideal.

If this fails what else???
One of the reason the foot tends to fall to the inside is also the lack of plantar musculation ..otherwise known as flat feet. Flat feet will force you to have more weight on the inside of the foot, thus forcing the boot to bend more in that direction than it should.

If all these avenues have been investigated, there is still the issue of the strength of the skater's legs and the impact it has on the structure.
We tend to push too much in general in one direction and get our kids to specialize much too early. Develop the athlete first and then the skater, and finally the hockey player. The result will be better and more enjoyable for both. Involve your son in other activities that will enable him to improve his functional strength in the legs while having fun. The other added benefit of such situation is that he will also improve his coordination skills and all in all make him a better skater or better at anything he will undertake as a yong athlete.

The tread mill:
I am not a great fan of it for the technique. The best result I expect from the treadmill, is the conditioning. I disagree with the use of it for the technique because it does not allow you to do the proper stride since the gliding is extremely limited. It promotes too much a front to back motion, which is technically wrong.

Closing remarks:
I would simply check the skates and let your son develop while still working on his technique and when spring comes, let him play other sports. In the wonter you could do some skiing both alpine and cross-country would be awesome for him, if doing the cross-country you can practice the skating style and you get a better understanding of the "on ice skating stride" as well as strengthen the leg muscles while spending time together as a family. Not a bad way to spend time and teach the kids something at the same time.

I sincerely hope this helped and will help you finding a solution.
You said in the previous bit of information that you had a hard tiam to reach me via e-mail, I am surprised. You can send me a vieo of your son skating and I will send you a very detailed anylisis of his skating skills.

Take care and keep the fun!