What is the central question of this study? In the present study, a reproducible model of maternal voluntary physical activity was developed to evaluate the adaptive response of physical activity by attenuating the effects of maternal undernutrition on physical features, reflex ontogeny and growth trajectory of offspring during development. What is the main finding and its importance? Maternal physical activity may induce neuronal maturation of sensorimotor connections impacting on the patterns of locomotor activity in malnourished offspring. Thus, physical activity should be considered as a therapeutic means of countering the effects of maternal undernutrition, by providing a useful strategy for enhancing the neuronal activity of children born to mothers who experience a restricted diet during pregnancy. This study evaluated the effects of maternal voluntary physical activity during pregnancy and lactation on somatic growth (SG), reflex ontogeny (RO) and locomotor activity (LA) of rats whose mothers were protein restricted. Virgin female Wistar rats were divided into the following six groups: control, normal protein (C-NP, n = 4); control, low protein (C-LP, n = 4); inactive, normal protein (I-NP, n = 8); inactive, low protein (I-LP, n = 7); very active, normal protein (VA-NP, n = 8); and very active, low protein (VA-LP, n = 6). Voluntary physical activity was recorded daily in dams. The LP groups were fed an 8% casein diet, whereas control groups were fed a 17% casein diet during pregnancy and lactation. Offspring were evaluated in terms of SG (body weight and length, latero-lateral skull axis and anteroposterior head axis) and RO (palmar grasp, righting, free-fall righting, negative geotaxis, cliff avoidance, auditory startle response and vibrissa placing). The LA was evaluated at 23, 45 and 60 days old in the open field. Voluntary physical activity was reduced during pregnancy and lactation independent of the maternal diet. Pups from LP dams showed delayed SG, reflex maturation and patterns of LA when compared with control pups. The C-LP and I-LP pups showed a delayed SG, RO and LA. Pups from VA-LP mothers showed no delay in SG and RO and presented a faster development of patterns of LA. Maternal voluntary physical activity attenuated the effects of LP diet on indicators of neurodevelopment and patterns of LA of offspring.