The aim of this article is to introduce a set of work physiology methods for the assessment of physical load at the work site and to consider (a) their relevance for different types of muscular work, and (b) their feasibility for occupational health and safety practitioners. The results of an ergonomic intervention study for the reduction of workload associated with various manual materials handling tasks were used for the evaluation of the feasibility and sensitivity of the measurements of heart rate, the Edholm and OWAS methods, and the ratings of overall and local perceived exertion. The methods proved feasible, although time consuming, and their sensitivity for the quantification of small changes in physical workload was limited. Despite these shortcomings, these methods can be used by occupational health and safety practitioners when their strategy and data collection techniques are developed further. In conclusion, there are relevant and feasible methods fora reliable work-site assessment of cardiorespiratory and postural load related to the activation of large muscle masses. On the other hand, field methods for the quantification of local static workload and repetitive type of workload with small muscle masses are scarce.