The means and standard deviations for the 3 measures at term age, 6 weeks of age, and 12 weeks of age are presented in Table 3. Cohen d effect sizes ranged from 0.73 to 6.61 (Tab. 3), suggesting differences in the means between the groups were medium-large to very large.40 Measurements of AO, AMax, and AO to AMax for both groups over all 3 ages are represented in Figures 3 and 4. Differences in MTU length (AO and AMax) and muscle belly stretch (AO to AMax) between infants born preterm and infants born full term were all significant (Tab. 4). At term age, 6 weeks of age, and 12 weeks of age, infants born preterm demonstrated values of AO and AMax in positions of greater plantar flexion, with a larger range of AO to AMax, compared with values in infants born full