Table 3.

Observational categories

Primary observational categories	Explanation
Physical activity level of group	Observed physical activity behaviour of all members of a group. We recorded all observed aspects concerning physical activity and inactivity. Furthermore, we differentiated between ‘very active’/‘moderately active’/‘rather passive, sometimes in the water, with a maximum of two short active exceptions’/and ‘extremely passive’.
Research setting	Champagne Pond or Entringen Pool
Gender composition of group	Male only/female only/mixed
Combination of group concerning age	Concerning age, we differentiated between ‘children’/‘adolescents’/‘young adulthood’/‘middle adulthood’/and ‘seniors’.
Combination of group concerning body shape	Concerning body shape, we differentiated between ‘lean, normal-weight, and slightly overweight’/‘clearly overweight’/and ‘athletic’.
Group size	In this category, we differentiated between small groups including two or three members/middle size including four or five members/large groups including six or more.
Additional equipment	We observed whether groups had equipment such as chairs, sun loungers, barbecues, cooling boxes, sunshades, etc. or not.
Communication level within group	We observed the verbal communication of group members, e.g. loud or quiet. Moreover, we differentiated between frequent and lively verbal communication between most group members/occasional verbal communication/almost no verbal communication among group members.
Food and drinking behaviour	We recorded whether groups brought food and drinks to the sites.
Secondary observational categories	Explanation
Design of resting site	We observed, how groups organised their resting site, for example how they arranged their equipment, how they furnished their site etc.
Figurations	We observed in-/out-group constellations, age combinations at the site and group compositional changes.
Social contagion	In this context, we looked at the spread of activity within groups and between groups.
Area of rest and movement	We observed where members of groups spent the majority of their time resting and the other areas they moved to.
Promoting physical activity	We used this category for coding all factors which appeared to promote physical activity.
Hindering physical activity	We used this category for coding all factors which hindered physical activity.