Reach to the left varied between 500 and 900 mm while that to the right was about 900 mm. The movement across from left to right required an effort that was partly static (supporting a weight of 3 kg) and partly dynamic, and each turn was accompanied by slight bending and twisting of the trunk. The factory introduced a 'new method' of knotting the ends of the fibres but this did not produce the improved performance that was expected. Therefore, the question arose of whether the operators might be physically overstressed.