The German Federal Institute for Occupational Safety and Health (BAuA) has been carrying out a project titled "Head mounted displays - conditions for safe and strain optimized use". One focus within the project was the influence of prolonged work with different head mounted displays (HMDs) in different assembling settings on performance, mental and physical strain while comparing the HMD to a wall mounted monitor and a tablet computer. A primary ANOVA analysis showed age effects regarding performance and some of the strain measurements. Present work contains a complete reanalysis of three laboratory studies using multiple regression to get valuable insights into the nature of age influences on performance and strain. In the first study, participants constructed Lego models. Here, the age of participants had a major influence on performance independent from display type. Regression analysis revealed that the predictors "age" and "technical affinity" led to highly significant regression models explaining 59% - 70% of variance in data. In a replication of this study with consumer products "age" was beneath display group again a valid predictor explaining 60% of variance. In the third study participants were assembling and disassembling a real car engine. Here "age" and "technical affinity" were rejected as predictor while display group explains about 10% of variance in task execution time. This illustrates that the "age" factor is highly task dependent and might have bigger effects on the fine motor skill demanding toy assembling task compared to the physically demanding work on a car engine. Within the paper, regression analyses of strain parameters are also discussed and regression models are presented and compared. This work helps to identify the influence of age within scientific research on new technologies like HMDs.

This article is published in the Journal "Procedia Manufacturing", 6th International Conference on Applied Human Factors and Ergonomics (AHFE 2015) and the Affiliated Conferences, AHFE 2015, Volume 3, pp. 4322-4329.