ngl2010:Actually, most of the time it's the kids who carries more things than the need to. Extra story book when they need to bring only one... unnecessarys stationery items like hole punchers, staplers etc. pack of animal kaiser cards etc. So it's a good initiative that schools are proactive in getting the kids not to bring unnecessary items to school. Having said that, most people focus only on the weight of the bag. How you carry the bag is equally important.Since a new principal came in a few years ago, the school disallow children carrying more than 4kg. From time to time they conduct checks. Since then, we only buy bags that are very light (no layering, no extra padding, etc) like those from Nike. It is also cheaper compared to the previous bags we had such as ergonomic bags, bags with wheels, etc.
By the way, please don't think too long term. My son refused to carry anything with cartoon pictures on it since P4, so some bags gone wasted.
Very often, the shoulder straps aren't tightened properly and the bag goes drooping down below the waistline and the kids walk around slouching forward. Padding is nice to have but are just for comfort on the skin. What is more important is that the bags have a reinforced base that allows the bag to sit on its own on the floor and withstand wear and tear... and also have a frame that allows the child to carry the bag without feeling the strain on her shoulders and spine. In this regards, the German bags are great. If you can't afford the price tag, there are cheaper alternatives including Dr Kong and Totem.