Fig 14.5 From Butler DS 2000 The Sensitive Nervous System, Noigroup, Adelaide
A tensioner is when the nervous system is pulled from both ends. For example, in the slump test, when neck flexion and knee extension, both of which physically load neural tissues are performed together, we refer to this as a tensioner, (i.e. "pulling from both ends"). If the knee is extended and the neck extended at the same time, we refer to this as a slider. The slider is much less aggressive technique. Some people refer to the slider technique as “flossing” as in dental flossing.
Michel Coppieters and I published a paper on this in Manual Therapy, titled- “Do sliders slide and tensioners tension/” (email me if you want a copy). This upper limb cadaveric study on the median and ulnar nerves showed that a slider technique (eg elbow extension with wrist flexion) created much more nerve sliding than a tensioner technique and in comparison, hardly strained the nerves. The suggestion is that mobilising techniques for neuropathic pain states involving peripheral nerves can be made more specific. The gentle but marked sliding of nerves may be extremely therapeutic in aiding early restoration of nerve gliding surfaces and pathways post trauma, and assisting dispersal of inflammatory exudate in gliding pathways.