knotted line strength

Hello kchunks,
Your explanation is not very clear, as we are all confused as to what you are referring. Knots on the lines????
Knots on lines are only referred to as an emergency field repaired situation that helps you continue to enjoy flying instead of going home.....when you break a line.
Which is a signal to you that you are using worn out lines or you are flying lines that are not appropriate for the wind/kite configuration. In such case replacing or shortening all your lines to the same length should be done before your next flying day. It all depends also on what type of kite flying you enjoy, with a 4m.
It is a well known fact that a knot on the line weakens such line, and from my personal experience, it is especially more predominant in dual line flying, where the line breaks most likely near the handles, at the sleeved knot, or when the pilot is careless and leaves a knot from a tangle on the line.

Now in a 4 lines power kite situation, the brake lines "takes" less pressure than the main lines, but still you should not be flying with any knots on any lines, first it shorten the line in question, second it weakens it, en especially in strong wind if you need to apply the brakes then it can become problematic.
Any lines should not have knots at any times, but now what we are talking about is how to adjust your brake lines at the handles. Usually factory setting should not be disturb until you are comfortable with you kite, and kiting activity, as it is a setting which should allow you to enjoy a fairly wide range of wind. It has been stressed upon me during my first few buggy experience that "do not use the brakes" as brakes are used most likely only during the launch and sometime during the landing of your kite (flying out of the wind window to land, when possible, put less stress on your kite).
Adjusting the brake lines is part of the tweaking experience, but as thumb rule....if you cannot handle your kite in a specific windy day......then it is too big to fly for you for this day, so..........use a smaller kite.
As attachment you will see a pic of a PKD Buster 0.7 handle set-up, IT IS NOT a reference as the company uses a different method of brakes adjustment.
You will notice that I placed 2 additional knots on the bottom, for the purpose of this posting, which can be tweaked in many ways. Adding one knot at the time will shorten your brake lines a little at the time or you can "jump" your brake lines from one knot to another for a greater amount of adjustment.

If, like in the pic, this is the type of knot you are talking about, then you are safe, as such heavy "cord" is used just for that purpose. You can peruse thru this forum, if I recall properly somewhere someone posted a lot of info (or links) with pics on set-ups of all kinds.
Hope this help, if not to you directly maybe to someone else. Enjoy.
RMV :singing: