Living environment was associated with certain components of HRF, MC, and physical and sedentary activities of 7-year-old children in Suriname. Further research is needed to evaluate the development of urban children to provide information for possible intervention and prevention strategies.

Aim To identify and map studies that have assessed the effect of interventions on lower‐limb macroscopic muscle–tendon morphology in children with spastic cerebral palsy (CP). Method We conducted a literature search of studies that included pre‐ and post‐treatment measurements of lower‐limb macroscopic muscle‐tendon morphology in children with spastic CP. Study quality was evaluated and significant intervention effects and effect sizes were extracted. Results Twenty‐eight articles were identified. They covered seven different interventions including stretching, botulinum neurotoxin A (BoNT‐A), strengthening, electrical stimulation, whole‐body vibration, balance training, and orthopaedic surgery. Study quality ranged from poor (14 out of 28 studies) to good (2 out of 28). Study samples were small (n=4–32) and studies were variable regarding which muscles and macroscopic morphological parameters were assessed. Inconsistent effects after intervention (thickness and cross‐sectional area for strengthening, volume for BoNT‐A), no effect (belly length for stretching), and small effect sizes were reported. Interpretation Intervention studies reporting macroscopic muscle–tendon remodelling after interventions are limited and heterogeneous, making it difficult to generalize results. Studies that include control groups and standardized assessment protocols are needed to improve study quality and data synthesis. Lack or inconclusive effects at the macroscopic level could indicate that the effects of interventions should also be evaluated at the microscopic level. What this paper adds Muscle‐targeted interventions to remodel muscle morphology are not well understood. Studies reporting macroscopic muscle remodelling following interventions are limited and heterogeneous. Passive stretching may preserve but does not increase muscle length. The effects of isolated botulinum neurotoxin A injections on muscle volume are inconsistent. Isolated strengthening shows no consistent increase in muscle volume or thickness.

During childhood, muscle growth is stimulated by a gradual increase in bone length and body mass, as well as by other factors, such as physical activity, nutrition, metabolic, hormonal, and genetic factors. Muscle characteristics, such as muscle volume, anatomical cross‐sectional area, and muscle belly length, need to continuously adapt to meet the daily functional demands. Pediatric neurological and neuromuscular disorders, like cerebral palsy and Duchenne muscular dystrophy, are characterized by impaired muscle growth, which requires treatment and close follow‐up. Nowadays ultrasonography is a commonly used technique to evaluate muscle morphology in both pediatric pathologies and typically developing children, as it is a quick, easy applicable, and painless method. However, large normative datasets including different muscles and a large age range are lacking, making it challenging to monitor muscle over time and estimate the level of pathology. Moreover, in order to compare individuals with different body sizes as a result of age differences or pathology, muscle morphology is often normalized to body size. Yet, the usefulness and practicality of different normalization techniques are still unknown, and clear recommendations for normalization are lacking. In this cross‐sectional cohort study, muscle morphology of four lower limb muscles (medial gastrocnemius, tibialis anterior, the distal compartment of the semitendinosus, rectus femoris) was assessed by 3D‐freehand ultrasound in 118 typically developing children (mean age 10.35 ± 4.49 years) between 3 and 18 years of age. The development of muscle morphology was studied over the full age range, as well as separately for the pre‐pubertal (3–10 years) and pubertal (11–18 years) cohorts. The assumptions of a simple linear regression were checked. If these assumptions were fulfilled, the cross‐sectional growth curves were described by a simple linear regression equation. Additional ANCOVA analyses were performed to evaluate muscle‐ or gender‐specific differences in muscle development. Furthermore, different scaling methods, to normalize muscle morphology parameters, were explored. The most appropriate scaling method was selected based on the smallest slope of the morphology parameter with respect to age, with a non‐significant correlation coefficient. Additionally, correlation coefficients were compared by a Steiger's Z‐test to identify the most efficient scaling technique. The current results revealed that it is valid to describe muscle volume (with exception of the rectus femoris muscle) and muscle belly length alterations over age by a simple linear regression equation till the age of 11 years. Normalizing muscle morphology data by allometric scaling was found to be most useful for comparing muscle volumes of different pediatric populations. For muscle lengths, normalization can be achieved by either allometric and ratio scaling. This study provides a unique normative database of four lower limb muscles in typically developing children between the age ...