CLINICAL BOTTOM LINE
“How should I apply this information?”
This study provides evidence that infants born full-term and preterm exhibit differences in active ankle movement that may be influenced by passive gastrocnemius/soleus muscle tendon unit (g/s MTU) length. For infants born preterm younger than 12 weeks corrected-age, clinicians may consider measuring g/s MTU length and maximum active plantarflexion and dorsiflexion range of motion to monitor how passive g/s MTU length influences active ankle movement. If an infant born preterm consistently exhibits a shortened g/s MTU length, excessive active ankle plantarflexion, and reduced active ankle dorsiflexion, clinicians may consider including the following in the child's intervention plan: active/passive stretching of the g/s MTU, activities to encourage active selective dorsiflexion, and activities to encourage age-appropriate ankle movements in supported standing positions and during early gait activities.
“What should I be mindful about when applying this information?”
Clinicians should be mindful that this study does not provide evidence that a shortened g/s MTU length, excessive active ankle plantarflexion, and reduced active ankle dorsiflexion during supine kicking in early infancy contribute to later functional limitations, including the emergence of toe-walking. In addition, although infants in this study were born preterm, they were classified as low risk for developmental problems, implying that differences in g/s MTU length and active ankle movement may resolve with time and not significantly impact a child's developmental trajectory. To inform clinical practice, further research of infants born preterm at high risk for developmental issues is recommended to determine the relationship between passive g/s MTU length, active ankle movement during infancy, and the emergence of toe-walking.
Jeongah Kim, PT, MS
Barbara Sargent, PT, PhD, PCS
University of Southern California
Los Angeles, California