Assisted Exercise in Prematurity; Effects and Mechanisms

Inclusion Criteria: * Preterm infants born at post menstrual ages of 23-33 weeks gestation Enrollment occurs at post menstrual age of 30 to 35 weeks.if their projected stay based on standard clinical criteria is four weeks after enrollment * Enrollment occurs at post menstrual age of 30 up to 35 weeks, if their projected stay based on standard clinical criteria is 4 weeks after enrollment. * Birth weight appropriate for gestational age (AGA) using current CDC growth charts. AGA is defined as plus or minus 2 standard deviations above the mean or above the third percentile. * Tolerating full enteral feeds at greater than or equal to 100kcal/kg/day Exclusion Criteria: * Evidence of chromosomal or other major genetic abnormalities * Existence of current diseases or syndromes including: central nervous system or other neurological abnormalities chronic lung disease of prematurity requiring chronic use of corticosteroids, musculoskeletal diseases * positive infant toxicology screen(urine) for drugs or alcohol * Both parents are under the age of 18 years * Babies with tracheostomy * Babies receiving ventilator assistance with breathing * Babies receiving IV fluids