Why tension is all

Posted on Thu, 11 July 2013

One day, whilst chewing the fat with a certain hirsute German who happens to know a thing or two about kinbaku, I asked whether, if he were forced, would he chose good tension or accurate wrap placement? Admittedly, this was rather like the schoolboy questions which involve two equally unlikely and unsavory choices “Would you rather xxx or yyy?”. The devil and the deep blue sea. However, the reluctant answer was tension.

You might ask why? Quite simply, whilst you might get away with placing a wrap on a nerve but ones that move can cause a lot of problems. Apart from the obvious issues like them coming off and dropping somebody or moving into dangerous positions, they can create what is known as shearing forces. These tend to be more damaging that mere pressure. This is when a rope under load is dragged across the skin. Whilst this might remove skin by causing a rope burn, this is a minor inconvenience. The real danger is nerve damage caused by lesion, i.e. tearing. This type of injury tends to be more serious, so takes longer to heal but it is also likely to happen suddenly without warning. It can occur as the rope slips or is dragged out of position. The more violent the movement, the more the likelihood of damage. So be careful with lifts and transitions, especially if they are fast or dramatic.

This does not mean that you must tie with steel-like bindings as too much tension can create crushing forces due to the angle of the loads. Imagine the load in this diagram is a cross section of somebody’s torso, the sling is the wraps of a gote and the hook the attachment of your suspension line. It gives an indication of how forces change. What it doesn’t show is the load on the ‘chest’, however, real life experience suggests that it’s a trade-off. As load comes off the shoulders, roughly shown by the values on the diagonals, it transfers to the chest (bottom of the load) to a greater extent. Sloppy wraps tend to load the chest more than shoulders and vice versa. I suggest that the 2nd picture represents ‘too loose’ and the 4th ‘too tight’ but the 3rd, like the third bear’s bowl of porridge, is ‘just right’. I’m not saying this represents the perfect angle for your wraps! It is only to represent an idea. Get feedback from your partner. There is more to be learned about the correct tension from the person you tie than all the theory I can expound.Not just good tension but equal tension. This can rarely be achieved without dressing or clearing the wraps. This means carefully straightening them by lifting and running them between thumb and forefinger with a little bit of friction. A casual run with a hooked finger is not good enough. Ignoring this simple step can mean discomfort and loads being thrown mostly onto on half of the wrap resulting in dangerous pressure. load angles

Bear in mind that tension is no substitute for engineering. It is not necessary to tie tightly to achieve solidity for demanding situations. This is where third ropes and additional forms of anchorage can pay bonuses. Tie smart, not just tight.