Recent work out of the lab from Alex Bliss in collaboration Dr Jeanne Dekerle at University of Brighton has been published in Measurement in Physical Education and Exercise Science.
The study investigated extension and flexion of the knee during a continuous motion (reciprocal) or dividing the movements with a passive rest (nonreciprocal). This was to determine whether these types of assessment give significantly different results as which type of motion is used (reciprocal or nonreciprocal) and is often not reported in research literature.
It was found that the CON-TREX multijoint system is reliable between testing days, but that reciprocal and nonreciprocal methods often yield significantly different results. This is important as isokinetic dynamometry assessment is commonplace and the results obtained may be used to identify athletes at risk of knee injury (through strength discrepancies between the quadriceps and hamstrings musculature). It was recommended that experimenters or practitioners using isokinetic dynamometry for knee extension and flexion assessments report whether they are doing so with reciprocal or nonreciprocal movements.
The full link for the paper can be found here and you can follow Alex on twitter via @Al_Blis