All conventional backpacks are unbalanced
Here's the problem with conventional backpacks - they are inherently unbalanced. So once you are carrying any kind of non-trivial weight, you have to lean forwards to counterbalance the additional weight on your back. This throws out your natural walking posture, causing fatigue and discomfort. It's simply a law of physics.
Well designed front pockets can solve this issue
There is a small New Zealand company called Aarn that has been working with a respected ergonomics lab to offer an alternative. By adding pockets to the front using an integrated suspension system, you can counterbalance the load and regain a balanced and natural walking posture.
Here are the forces at play, as measured in the lab:
And here's a practical illustration of the difference this makes:
I can tell you from personal experience that the benefits over a long day are striking - less fatigue, complete freedom from pain in the back and shoulders, and significantly improved agility and balance. You also enjoy easy access to your gear.
The downside is increased complexity - it takes effort and experimentation to get the system dialed-in and it's a bit more hassle to get your pack on and off.
So what makes for an effective frontpack design?
There are obvious challenges to designing a frontpack system:
- You need to ensure good visibility for the feet
- You need to provide adequate ventilation for the chest and accommodate the female anatomy.
- You need to transfer the weight off the shoulders and down to the hip-belt.
Most frontpacks on the market don't do a great job with this. Here's the Zpacks offering, for example:
It obscures your view of your feet, sits directly on your chest, and hangs off the shoulder-straps, increasing the weight on your shoulders and spine.
But Aarn has pretty much solved these issues with his framed front pockets that offer good visibility and air-circulation, and transfer the weight directly to the hip belt:
He also offers pockets that will integrate with a conventional child-carrier to make life a little more bearable (pun intended):
I'm very interested in backpack design and am currently building my own version of the Aarn bodypack. I've searched extensively for innovations in the field, and the frontpack concept is the only approach with the potential to revolutionise the load-carrying experience. But doing it ad-hoc is unlikely to work well for you - the elements need to be carefully designed to work together as a system.