Sling bag vs. back pack vs. luggage bag?
Have you ever wondered why your shoulder or back is painful after carrying a bag? Or do you ever wonder if your children are getting the most suitable bags for their posture and growing body? Let’s now look at how each type of bag should be carried, and what the common problems may be when carrying a bag wrongly.
As we all use our shoulders to carry a bag, let’s start by looking at the normal structure of the shoulder. The shape of the shoulders is that the part that is near the base of neck is usually higher than the tip of the shoulder, so it creates a natural “down slope”. Therefore, when a sling bag is carried only on one shoulder, the tendency is for the bag to slide off the shoulder. In order to stop the bag from sliding, one usually needs to lift up the shoulder on the same side to level the “down slope”. This can eventually leads to overuse of the shoulder and neck muscles, and causes pain and stiffness.
The correct way to carry a sling bag is to carry it with its strap across the chest. By doing so, the weight of the bag pulls the strap towards the base of the neck (the “cross” effect), instead of slipping off the shoulder. Thus there wouldn’t be a need for the shoulder to elevate excessively. Another benefit of carrying a sling bag across the chest is that the weight of the bag can be supported by the hip or back, the downward pull on the shoulder is also lesser, which helps reduce the risk of over-using the neck and shoulder muscles.
There are many different designs of back pack, but they all share one thing in common: there are 2 straps and one on each shoulder. Hence, there won’t be any tendency for the bag to slip off the shoulder (as compared to the sling bag), so there will be less risk of shoulder / neck overuse injury. Speaking of which, that is provided the bag is indeed carried by the defaulted way: carried on 2 shoulders. If the back pack is carried on one shoulder with only one strap being used, it turns out to be another “modified sling bag”, and of course may lead to problems as mentioned above too.
Let’s say now we do carry the bag on both shoulders, does it mean one will definitely have a correct way of carrying it? The answer is “no”. Have you ever wondered why many parents complain that their school-going kids have terrible posture when they carry their school bags? So, what went wrong here?
When carrying a back pack, the length of the strap is most crucial: if too long, the back pack will “lean backward” instead of pulling straight “downward”; the backward “leaning” would encourage a body “forward leaning” or in some people “forward hunching”. This eventually leads to either a much hunched spine, or elevated shoulders, or both, giving rise to many back and shoulder problems such as back / shoulder pain or poor posture.
So the key is to adjust the length of the strap so that the back pack stays closely in contact with the back. If possible, look for bags that have front straps that cross the chest / abdomen, as those straps can hold the bag closely to the body. The closer and more firmly the bag is to the body, the less movement of the bags, and the less the body needs to work to carry it with you.
Pulling a luggage bag is probably easier for the back as the load now is on the ground. It has less impact on back posture (either good or bad to start with). But not to forget, if the length of the handle is not correctly adjusted, for example, if it’s too short, one needs to turn and bend to the side to pull the bag which may lead to back strain. On the other hand, if the length of the handle is too long, one would need to excessively lift the shoulder to accommodate the position of the handle, which is also not ideal for the posture.
The key here is to ensure appropriate length of the handle so that when you pull the bag, you shoulder should remain down and relaxed with elbow bent slightly. There shouldn’t be any turning or side-bending of the trunk too. Last but not least, the weight of the bag also should not be too heavy to cause possible arm muscle strain, especially when the travel time required is long.