Some examples are given in Table 6.3. shovelling is a common form of manual work, which has been thoroughly studied at the Max-Planck-Institut fur been arbeitsphysiologie in Dortmund, Germany (Lehmann, 1962) and, more recently, at Pennsylvania State University in the USA by Freivalds (1987). Both studies demonstrated that certain tool forms are better suitable than others to perform maximal work with minimal effort. The highest level of efficiency was attained when a load of 8-10 kg was shovelled 12-15 times per minute. In addition to the Table 6.3 Maximum efficiency in various