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Ankle Movements During Supine Kicking in Infants Born Preterm
Marybeth Grant-Beuttler1, Carolyn B Heriza, Robert J Palisano
1Department of Physical Therapy (Dr Grant-Beuttler), Crean College of Health and Behavioral Science, Chapman University, Irvine, California; Doctoral Programs in Pediatric Science (Dr Heriza), Rocky Mountain University of Health Professions, Provo, Utah; Department of Physical Therapy and Rehabilitation Sciences (Dr Palisano), Drexel University, Philadelphia, Pennsylvania; Department of Physical Therapy (Drs Reddien Wagner and Miller), Panuska College of Professional Studies, University of Scranton, Scranton, Pennsylvania; Department of Human Physiology (Dr Karduna), University of Oregon, Eugene, Oregon.
Background:
Knowledge of musculoskeletal factors that influence supine kicking of infants born preterm has implications for early intervention.
Hypotheses:
Differences exist between infants born preterm and full-term in ankle kinematics during supine kicking, which are attributable to passive measures of the gastrocnemius/soleus (g/s) muscle tendon unit (MTU).
Subjects:
Twenty infants born full-term and 22 born preterm were measured at term, 6 weeks, and 12 weeks of age.
Outcome Measures:
Ankle kinematics during supine kicking and g/s MTU length.
Results:
Infants born preterm demonstrated less dorsiflexion, more plantar flexion, and more total ankle range during supine kicking. Gestational age explained 69% to 85% of the variability in MTU length from term to 12 weeks of age. MTU lengths explained 0% to 42% of the variance in ankle kinematics.
Conclusions:
Passive measures of the g/s MTU may inform clinicians about ankle kinematics in newborns to 12-week infants during supine kicking.
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