Knitting lace - some notes about tentioning and posture

When one knits Russian lace of Orenburg most of gossamers start with bottom teeth ribbon
When about 5-10 teeth are done at this length the ribbon can be tensioned and the 'tail' can be held between the knees
Bottom pictures that show hands positioning for Russian knitting. Russian are "pickers".
The gray ribbon is tensioned between my knees, open stitches == speed increase
Angled at ~45degrees needles do same, so the close hand positioning to the needle point and minimum finger movements. In my case left needle is stable English knitters (throwers) would be mirroring, the have right needle stable.
The tensioned bottom teeth ribbon for Russian knitter would be slightly leaning to the left repeating the angle of the stable needle relative to the knitter's body. Shoulders are dropped so the tension in the neck is minimum, the body center of gravity is shifted above the pelvis, back has slight curve, naval to the spine.
If one does not know how... do the shoulder roll front to back and stop when the body comes to balance and shoulders are dropped, leave it there. At this point the elbows will come to close to 90 degrees angl and hands should relax. The posture will promote the human body to "hold the core". One holds themselves by the core muscles. Fingers are relaxed. Hunching the back would promote shoulder stress and tension, please avoid that. That's why holding yourself with the core lifting slightly up is a benefit - that back can not hunch in this position, it is against of rules of the gravity, however the tired body would tend to do the 'hunch' thing. If yours does that, it's time to call it quits and do some exercises and rest and maybe consider to re-train the body. For some it's important to re-learn the posture and how to sit without stressing the back, neck and hands. One may choose  to consult a specialist for that and it's a well spent money.
Why is it important or even is mentioned... Human hand and small knitting motions == risk of repetitive motion stress. The nerve that gets stressed in some jobs and ends up as carpal tunnel or relead issue is the same nerve that goes from the back inside the shoulder throuhg the elbow and through the wrist. Everything in the human body is connected. That notorious neck stres when folk type long hours at computer and sit not correctly has the same root cause that a lace knitter who has positioned the body in not a beneficial way can create. Stress causes inflammation and the nerves get affected in the end. This can build up in the body. The goal here is to find the own body balance that will promote the shoulder, elbow and wrist to relation while knitting and function with the minimum stress and body tension.
This kind of technique does reduce body stress during longer knitting hours. If the shoulders become stresses please take it as a signal to do some stretching and helping the body to regain it's strength and relax. The long hours of lace knitting are acomplished through proper relaxation of the body and mind and through light hands, not the 'bear grip', stress and fighting that lace to the end :), please do not fight the lace, please listen to it and to your own body.

Tension lace later in the process when the corners are turned:
Rock :)  . The weight is placed on your knees. A small rock from outside wrapped in  a stretchy fabric and tied with a crochet thread will do just fine. Inside of mine is a small piece of granite. I mean do not look for a boulder :). Ok, joke it's over, but I did see once a knitter to pick up quite a heavy thing as a lace weigh... No holding that weight by the hands, the purpose of it to open the stitches enough to promote the speed of the knitting and more even stitches, nothing more. Lace knitters pros put longer hours. The use techniques to minimize the body stress.
The lace is tensioned using crochet thread and 5-th hole of the tooth. Large needle or a hook to pull the thread through, bobbin pit also works fine for that purpose. Crochet thread will not break most of the yarns if one does not pull hard on it (that's why rock does rest on the knees and not more tension than that)

Good luck and happy lace knitting.