Plus you should keep the heaviest stuff at the top of your rucksack.
Yea, and just to add: try to pack the weight close to your pack too, makes much better balance
To Keegan,
I dont know when you are going to France, but if you are not used to walking with a backpack you should start with a quite low weight (10-15 kg) depending on how fit you are, and gradually increase the weight until you reach about 25 kg. On some occasions you should problably try to walk with 30+kg backpack just to know how it feels and how your body responds to it, but dont hurry about that. A 6 kg backpack is too low in my opinion, unless you are very unfit and have a lot of time to prepare until you enter the legion
Another great tip mentioned is keeping a fast pace. The normal preferred walking pace is somewhere around 5-5,5 km/h in civil life, but get used to walking faster than that. From personal experience i found it quite hard in the beginning to adjust to a fast marching-pace in the military, and i guess some units might have a higher tempo than others. We did at least 6, sometimes 7km/h and a little more, and you should expect something like that pace in the Legion as well. Heck, we did a exercise with some special naval warfare unit and they had the highest pace i have ever experienced. Most guys would have to run while they was walking.
Of course, high pace walking is done with a little lighter backpack.
As for distance, i believe the 5500 m walk to the gym + 5500 m walk back from the gym sounds good if kan keep up doing it for all the months until you join the Legion. For example: 11(5500m+5500m) kilometers of walking with a backpack 2-3 times a week with high pace + 1-3 days a week with longer march with a heavier backpack but with lower pace (Stoeng recommends 4-5 hours walking with 20kg).
If you get tired of walking all these 5500m to and back from the gym, you can jog to the gym instead. You dont need a backpack, but if you need to have some things with you there should be no problem jogging 5500+5500m with a backpack weighing a few kilograms. Try to keep the backpack weight as low as possible when jogging, 6kg backpack when jogging is a "lot", unless you are experienced jogging with a backpack, as backpackjogging can be hazardous to the feets. Stoeng (Norwegian leggionnaire with 15 years experience, who made a workout plan on this forum) recommends a ca 1,5 hour jog about every second day. That will fit very good into your 5500m+5500m to and back from the gym.
I dont know how fit and experienced you are, but try to regulate your backpack weights, walking tempo etc so you dont get annihilated in the first weeks. Steadily progress.
Stoeng also mentions how to march/jog if you live in urban areas, like Alexandria. This is what he says:
Running on tarred roads is forbidden; stay on dirt roads in the woods or in parks (if you are such an urban wimp).
Basically: tarred roads is quite hard for the feets so running a lot on that might get you injured, and i bet the Legion does most of its marches in the woodland and not on tarred roads.
I have never used double socks so i have no experience with that, but i have heard its popular and that it works. A good pair of wool socks does the trick and might make a double layer of socks unnecessary. Test it out yourself.
Remember to walk-in your marching boots GOOD. My tip is to soak them in water and walk for at least an hour in rural areas to make the boots fit good to your feet.
The best will be to walk a lot with the boots, and the boots will adjust to your feet.
Do some readings on how to tape your feet with athletic sports tape. I have never ever gotten a blister when using a my walked-in boots and with taped feets.
Summary: Get good at walking fast with a lighter backpack. Get good at walking in normal tempo with a heavy backpack. Get good at running (Stoeng says 13 km in 1,5 hour) and do AT LEAST 7 pull-ups, ideally more than 7. Stay injury free.