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Gastrocnemius-soleus muscle tendon unit changes over the first 12 weeks of adjusted age in infants born preterm
Marybeth Grant-Beuttler1, Robert J Palisano, Debra P Miller
1Department of Physical Therapy, Chapman University, Orange, CA 92866, USA. beuttler@chapman.edu
Insights
Infants born preterm have differences in gastrocnemius-soleus muscle and tendon lengths compared to full-term infants. These musculoskeletal differences may impact motor development and functional changes in preterm infants.
Area of Science:
- Pediatric musculoskeletal development
- Neonatal physiology
- Motor development research
Background:
- Gastrocnemius-soleus muscle and tendon lengths differ between preterm and full-term infants shortly after birth.
- Understanding these differences up to 12 weeks of age is crucial for insights into motor development in preterm infants.
Purpose of the Study:
- To compare gastrocnemius-soleus muscle tendon unit lengths in preterm and full-term infants.
- To analyze changes in muscle and tendon lengths from term age to 12 weeks corrected age.
Main Methods:
- Gastrocnemius-soleus muscle tendon unit lengths were measured at term, 6 weeks, and 12 weeks corrected age.
- Measurements included taut tendon relaxed muscle length (A(O)), taut tendon stretched muscle length (A(Max)), and muscle stretch (A(O) to A(Max)).
- 20 full-term and 22 preterm infants participated in the study.
Main Results:
- Significant differences in A(O), A(Max), and muscle stretch were observed between preterm and full-term infants.
- Preterm infants showed greater plantar flexion in A(O) and A(Max) measures.
- Both groups exhibited significant A(O) lengthening between term and 12 weeks corrected age.
Conclusions:
- The study provides valuable data on gastrocnemius-soleus muscle and tendon development in infants.
- Observed musculoskeletal differences align with theories of uterine confinement during late gestation.
- Findings are relevant for assessing the musculoskeletal system in preterm infants with functional changes.
Background And Purpose:
Differences in the gastrocnemius-soleus muscle and tendon have been documented shortly after birth in infants born preterm compared with infants born at term. Knowledge of muscle tendon unit lengths at term age to 12 weeks of age in infants born preterm may be useful in understanding motor development.
Participants And Method:
Gastrocnemius-soleus muscle tendon unit lengths were compared at term age, at 6 weeks of age, and at 12 weeks of age (preterm adjusted age) in 20 infants born full term and 22 infants born preterm.
Results:
Significant differences were found between the 2 groups on taut tendon, relaxed muscle length (A(O)); taut tendon, stretched muscle length (A(Max)); and muscle stretch (A(O) to A(Max)). Infants born preterm demonstrated measures of A(O) and A(Max) in positions of greater plantar flexion compared with infants born full term. Significant differences in measurements of A(O) were found between term age and 12 weeks of age, indicating that the tendon lengthens during this period for both groups.
Discussion And Conclusion:
These results provide knowledge of musculoskeletal development of the gastrocnemius-soleus muscle and tendon. Differences in musculoskeletal measurements are consistent with uterine confinement in the last weeks of full-term gestation. These findings have implications when examining the musculoskeletal system in infants born preterm who are demonstrating functional changes.
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