2007, Piran, Slovenia

Environmental Ergonomics XII
Igor B. Mekjavic, Stelios N. Kounalakis & Nigel A.S. Taylor (Eds.), © BIOMED, Ljubljana 2007
212
PROTECTIVE CLOTHING AND ITS EFFECTS ON RANGE OF
MOVEMENT
Lucy Dorman, George Havenith
Environmental Ergonomics Research Centre, Dept of Human Sciences, Loughborough
University, Loughborough, Leics, LE11 3TU, UK.
Contact person: g.havenith@lboro.ac.uk
The extra bulk and stiffness of personal protective clothing (PPC) can create a number of
ergonomic problems for the wearer, which can have a negative effect on performance, such as
reducing mobility and increasing energy consumption. The nature of the protection required
in industries where workers are exposed to extreme cold, heat and fire often means garments
are constructed of thick and heavy insulative material. The impact of these garments on ease
of movement, range of motion and work efficiency has been observed by many authors, and
this is frequently described as a ‘hobbling effect’. However, detailed investigation into this
effect has been limited.
Seven PPC garments were tested, selected on the basis of their clothing bulk and previously
recorded significant increases in metabolic rate when worn. Range of movement was
measured with two goniometers attached to the skin across the knee and hip joints. Six
participants completed three work modes in all garments, and in a control condition (shorts
and t-shirt). The work modes were walking, a stepping sequence (stepping over a number of
steps) and a crawling sequence (stepping over, bending and crawling under obstacles) with
participants’ speed controlled by a metronome. The stepping sequence was made up of six
stages, and the crawling sequence of four stages.
Rather than a general, uniform change, individual data tended to show one of three trends: (1)
very little change in joint angles when clothing was worn compared to a control state; (2)
reduced joint angles when wearing the clothing; and (3) increased joint angles when the
clothing was worn. Overall, statistically significant reductions in knee range of movement due
to the PPC were observed during stepping in five of the six stages, and for some of the
crawling stages (which also promoted changes in the hip angles).