Social influenceFamily interaction [PA & SB]

One grandparent mentioned that the presence of the partner or the aunt of the grandchild(ren) while providing grandchild care changed the type of activities conducted with the grandchild(ren). When being alone as grandparent while taking care of the grandchild(ren), the grandparent was asked to play along with the grandchild(ren), who performed mostly physical activities. When the partner or the aunt of the grandchild(ren) was at home, more sedentary activities such as tinkering were merely chosen to be done with the grandparent, while the grandchild(ren) preferred to do the physical activities with the grandparent’s partner or the aunt being present (see Table 6, Quote 16).

Additionally, different grandparents mentioned that the help and availability of a partner made it possible to switch between more intensive physical activities with the grandchild(ren) and some less exhausting activities such as preparing lunch. Furthermore, the sometimes exhausting activities in relation to providing grandchild care could be more distributed across both grandparents.

Grandchild(ren)’s parents Compensation for busy parental life [PA only]

A number of grandparents mentioned the fact that the parents of the grandchild(ren) were very occupied with their careers and the own household and, therefore, did not have the time to be always 100% available for their children at home and, for example, had little time to plan specific activities. As a compensation and due to the fact that grandparents probably have more free time, grandparents tend to pamper their grandchild(ren) when taking care of them by doing some extraordinary activities outside the home such as going to a theme park, visiting a zoo, and thus providing all their attention to their grandchild(ren), resulting in higher levels of PA (see Table 6, Quote 17).

Parental control [SB only]

Spending time in front of screens was for some grandparents not an option as activity, as this was prohibited by the parents of the grandchild(ren), pursuing a healthy lifestyle (see Table 6, Quote 18). Other parents learned their children to time and thus limit their screentime to ten minutes per occasion, resulting in less time spent sedentary by both grandparent and grandchild(ren) when grandchild care was provided by the grandparents.

Grandparent partners’ physical health [PA & SB]

One grandparent mentioned that the own physical activities while caring for the grandchild were limited because the partner suffered from back problems. As grandchild care was provided most of the time by both grandparents together, physical activities were limited to short walks, while the rest of the time more sedentary activities, such as making a puzzle, playing with blocks or watching some television were done with the grandchild concerned while providing care together with the partner (see Table 6, Quote 19).

Characteristics of the grandchild(ren)Number of grandchild(ren) to take care of [PA & SB]

One grandparent mentioned to like having all the grandchildren around at the same time. This resulted in more possibilities for activities and games, both active and sedentary, making it more fun for everyone. Another grandparent told that having twin grandchildren asked more PA of her compared to the care she was used to when only having a single grandchild to care of, as she had to have an extra pair of arms and eyes to keep them both calm and busy (see Table 7, Quote 20).

Sex of the grandchild(ren) [PA & SB]

One grandparent mentioned that when taking care of the granddaughters and giving them the possibility to choose the activities, they rather chose more sedentary and inside activities compared to when taking care of the grandsons. Although both the granddaughters and grandsons did also activities together, it was likely that the granddaughters would choose some creative activities to do inside with the grandmother, such as tinkering, while the grandfather would be more active together with the grandsons, such as playing football outside (see Table 7, Quote 21).

Age-related physical/motor development [PA & SB]

Overall, the age of the grandchild(ren) seemed to be an important factor for the grandparents to be more or less physically active on days of providing grandchild care. In almost all of the cases, having to take care of older grandchild(ren) meant a wider range of possible activities because of their more extensive locomotor possibilities, a wider movement area, and the fact that their repertoire of activities more and more resembled every day activities of the grandparents themselves. As younger children have a relatively small movement area, having not yet reached their maximum potential from a locomotor point of view, many grandparents mentioned that their level of PA while caring for grandchildren aged around or being younger than two years was lower compared to days without grandchild care. Yet, their level of PA seemed lower during days of providing care compared to those in absence of the grandchild(ren), because the grandchild(ren) were not yet able to perform the chosen activities (e.g., going for a walk) at the same intensity and over the same distance as the grandparent was used to. However, the grandparents of these younger grandchildren (i.e., aged around or being younger than two years) mentioned to be constantly busy with the grandchild(ren) (as they were too young to be left alone) and to feel exhausted after a day of providing care (see Table 7, Quote 22).

Furthermore, with increasing age of the grandchild(ren) also the interests of the grandchild(ren) changed. For example, one grandparent noticed that the grandchild(ren) asked more often to watch some television once they became older, resulting in more sedentary time for both the grandchild(ren) and the grandparent (see Table 7, Quote 23).

A number of grandparents mentioned that their own activity level differed on days of providing care compared to days without taking care of their grandchild(ren). Most of them were more physically active on days without grandchild care, because the daily activities of the grandparent in absence of the grandchild(ren) were too difficult to combine with providing care for the grandchild(ren) due to the child(ren)’s locomotor possibilities. Therefore, the daily activities were not executed as usual. Some grandparents tried to keep up with their daily activity schedule, such as going for a bike ride together with the grandchild(ren), although this was not possible at the same intensity as when the grandparent would have done this on his/her own (see Table 7, Quote 24).

Furthermore, some participants mentioned that the activities or movements, specifically related to taking care of young children (such as bending, lifting, sitting and playing on the floor), were quite intensive and rather uncomfortable for their age. One of these grandparents even told to experience some back pain at the end of a day of providing grandchild care (see Table 7, Quote 25).

Some of the participating grandparents had multiple grandchildren with a relative large age difference between them. These grandparents told that it was almost impossible to be physically active with all grandchildren together as the youngest ones were not able to do the activities the older ones could already conduct. This often resulted in more adjusted and sedentary activities, and thus a lower level of activity for the grandparent (see Table 7, Quote 26).

Age-related cognitive development [SB only]

Besides the physical/motor developmental level, children also advance in terms of their cognitive capacities with increasing age. According to the grandparents, this resulted in the ability to understand how to play board games, yielding more sedentary activities from the moment the grandchild(ren) were cognitively able to play along (see Table 7, Quote 27).

Health of the grandchild(ren) [SB only]

Grandparents told they were less active on days the grandchild(ren) were not feeling well, as the main activity of the grandparent was then to nurse the grandchild(ren) instead of going for a walk or a bike ride together (see Table 7, Quote 28).

Character, mood and interests of the grandchild(ren) [PA & SB]

Some grandparents explained that the character of each grandchild plays an enormous role in the grandparent’s level of activity during the provision of care. Some grandchildren liked to play a lot inside and on their own, resulting in a lower level of activity for the grandparent concerned, whereas others needed a lot more attention in everything they do, which may result in a higher level of activity of the grandparents involved (see Table 7, Quote 29).

Some of the grandparents intervened in choosing what activities were done while providing care at moments where the grandchild(ren) became moody. In some cases, the grandparents chose to do some physical activities such as going for a walk to see and feed ducks, for example (see Table 7, Quote 30). However, in other cases this resulted in some more sedentary time together with the grandchild(ren) by watching a movie or reading a book aloud. This was mentioned by a grandparent explaining screentime was allowed when the situation asked for it. For example, when the grandchild(ren) was/were tired and needed some time to become calm. These were moments the grandparent allowed screentime and thus spent some time sedentary together with the grandchild(ren) (see Table 7, Quote 31).

Almost all activities mentioned by the grandparents during the provision of grandchild care were based on the interest(s) of the grandchild(ren). Many grandchildren of the participating grandparents liked to read a book aloud, to watch a movie or to make a puzzle together, resulting in sedentary moments for the grandparent. However, many grandchild(ren) also liked to dance, to walk or to swing, resulting in activities which were more physically active for the caregiving grandparent (see Table 7, Quote 32).

Many of the grandparents considered the fun factor of the activities they chose to do with their grandchild(ren), so the grandchild(ren) would enjoy it and as a result be satisfied about being with their grandparents (see Table 7, Quote 33).

New experiences of the grandchild(ren) [PA only]

The physical activities of one grandparent in particular while providing grandchild care were physical games the grandchild(ren) learned at school or during camp(s). As a result, the grandparent was physically active a lot during such games (e.g., playing tag) (see Table 7, Quote 34).

Grandchild(ren)’s planned activities [SB only]

Grandparents mentioned that sometimes during the period they took care of the grandchild(ren), they were responsible for driving the grandchild(ren) around to their hobbies. Therefore, the grandparents were mainly restricted to being sedentary in their car, as multiple grandchildren had to be driven around to different after-school activities at different times of the day (see Table 7, Quote 35).

Nap of the grandchild(ren) [PA & SB]

The nap of young(er) grandchild(ren) was cited multiple times as a reason for some less intensive PA while providing childcare. As the grandchild(ren) had to sleep at noon, the house of the grandparent had to be calm and quiet. Because of this, most of the grandparents chose for a calm and sedentary activity themselves at the time of this nap. However, for some grandparents this was an adjustment, as they mentioned to be normally quite active during the day, without any interruption. For other grandparents, this moment of rest during the day was very welcome (see Table 7, Quote 36).

Table 6 Quotes about factors of grandparents’ physical activity and sedentary behavior on the interpersonal (social influence) levelTable 7 Quotes about factors of grandparents’ physical activity and sedentary behavior on the interpersonal (characteristics of the grandchild(ren)) level