In 1963-1972 he was working as a junior and then senior researcher in Institute of Psychology, Russian Academy of Pedagogical Sciences under the supervision of Boris Teplov and Vladimir Nebylitsyn.

This work included a comparison of the EEG recordings and performance on various tasks of individuals with different endurance, tempo, plasticity and emotionality.

From 2009 he worked as a Leading Researcher in Drujinin Laboratory of Abilities and Mental Resources, Institute of Psychology under Russian Academy of Sciences.

Rusalov suggested that temperament traits be assessed using four scales:[15][2][4][6] each evaluated separately in three areas of activity: social, physical and intellectual.

[2][3][4][6][15][22][23] The first version of the English version of the STQ came out in 1989 [15] and had in total 8 scales: four scales Ergonicity (endurance, the ability to keep intensive work), Plasticity (or flexibility, the ability to effectively switch between tasks or to change the way of performance), Tempo, and Emotionality assessed in two types of aspects of activity, physical-motor (Motor) and social-verbal (such as reading, writing, speaking, communication).

The benefits and novelty of the activity-specific approach developed by Rusalov were that it offered a differentiation between traits that was missed in previous models of temperament and personality.

This approach, i.e. differentiation between physical, verbal and mental aspects of activities was used in the neurochemical model of Functional Ensemble of Temperament developed by Irina Trofimova in 2007–2014.

Another benefit and novelty of the activity-specific approach was that it integrated the principle of habit formation in behavioural regulation into the structure of psychological individual differences.