Credits to YouTubers and who have great vids on this topic, and I'm sure others do as well.
Currently level 48 with Elite Strength and level 40 Endurance. Achieved Elite strength probably around level 44ish.
AT THE START OF THE RAID burn one entire stamina bar while only running (further you go, more skill points you’ll earn). This will give u a 1.29x multiplier on the entire skill points earned for that stamina bar if you do it uninterrupted. The points are calculated on DISTANCE TRAVELED, so don't run in circles or into a wall. Due to diminishing returns, you will earn significantly less skill points as the raid continues. This is the absolute best way to earn skill points for both endurance or strength, depending on if youre overweight or not (overweight as in your weight is coloured yellow in your inventory screen). This 1.29x multiplier is only present until you receive your first skill point – which is way before your first stamina bar finishes, BUT will count for the ENTIRE bar as long as the buff is present to begin with. On the skill tab, each skill either has a blue, red, or no arrow, all are blue at the start of the raid. This is why at the start of the raid it's a good idea to burn that bar before you do half sprints and only gain a couple points from the multiplier.
Other tips:
Use stims to increase your max stamina. Max stamina = longer sprint = more skill points with the 1.29 multiplier. SJ1, SJ6 and probably a couple others. *APPARENTLY* BSG might have removed the skill point xp gain from the bonus stamina, haven't confirmed.
Be just barely overweight at the start of a raid with a backpack or stuff in your backpack. Drop your backpack, burn your stamina bar as per above, pickup your backpack, do the same thing, this time levelling up your strength.
The various options for gear vary a lot in weight. Try to compromise with lightweight options so you can still carry the other things you want like extra mags/nades etc.
Get Air Filtering Unit in your Hideout.
Lastly, endurance and possibly strength both 'scale' off of themselves, which means at higher levels, you'll increase them at a faster pace. This is because endurance gives you more stamina, and as we know more stamina = further distance ran = more skill points. Strength gives you faster sprint speed, which might also equate to further distance ran.
Just tested offline and I get about 6 points for my first stamina bar, and only 1.6 for my second and 1.1 for my 3rd, so you can see how bad diminishing returns hits you.
If there's anything I missed or misinformed please comment and allow me to fix it.
