This study explores how a physical activity program can affect hormone health and diabetes risk in girls ages 8-12 who may be at higher risk. The study aims to address:

• Does the 'ActiveGirls' program meet the needs of girls and families in engaging them to increase physical activity?
• What is the trend of markers of diabetes risk and puberty hormones over a 1-year period and how are these levels related to physical activity levels?

Participants in this study will either:

• Participate in a 'full' intensity intervention that includes educational messages (text/email) as well as health coaching visits to support physical activity over a 6 month period
• Participate in a delayed 'lower intensity' intervention that includes only educational messages (text/email)
• Participants in both groups will complete at-home activity monitoring, two study visits for check-ups and tests, and surveys

This study is a pilot randomized trial to assess the preliminary feasibility and efficacy of a physical activity intervention enrolling peripubertal females.

Participants will be assigned to the intensive intervention group with text messaging and health coaching versus delayed lower intensity comparison group with a lower intensity text-only intervention. Participants in both arms will complete objective measures of body composition, insulin dynamics, reproductive hormones, physical activity and fitness over a one-year period. Participants as well as a caregiver proxy will complete survey measures addressing lifestyle behaviors and social-emotional wellness. Given evidence suggesting increased effectiveness of whole-family lifestyle interventions, a parent/caregiver will assist with child participation in the ActiveGirls program, including facilitating health coaching visits and at-home physical activity sessions. assist in intervention delivery and outcomes assessment.

After the baseline visit, there are 2 more study assessment points at 6-months and 12-months. The baseline and 12-month assessments require in-person visits to the MGH Translational and Clinical Research Centers (TCRC); the 6-month assessment is performed remotely. All study visits will occur at MGH.

Inclusion Criteria:

• Caregiver: Caregiver of child (ie mother, father, or other legal guardian), English-speaking, Access to a device where they are able to receive study e-mails or texts
• Child: English-speaking, Female, ages 8-12 years old at time of enrollment, Pre-menarchal at time of baseline visit, at risk for Polycystic Ovary Syndrome (PCOS)/insulin resistance, as defined by (1) History of maternal PCOS/maternal GDM, (2) BMI >/= 85th percentile, (3) History of premature adrenarche, or (4) Small (<10th %ile) for gestational age

Exclusion Criteria (Child):

• Medications at time of enrollment: Metformin, GLP-1R Agonist, Insulin, GnRH agonist
• Endocrine conditions that would impact either insulin sensitivity, androgen concentrations, or growth
• Insulin dynamics: Type 1 diabetes, Type 2 diabetes, Congenital Hyperinsulinism
• Androgen Conditions: Adrenal tumor, Congenital Adrenal Hyperplasia
• Hyperthyroidism or uncontrolled hypothyroidism (TSH >7.0 mIU/mL)
• Growth Hormone Deficiency
• Medical conditions that would impact PA participation: Type 1 diabetes; Cardiovascular, neurologic, and/or musculoskeletal conditions limiting ability to participate in physical activity.
• Other medical comorbidities that would limit generalizability of findings, including: Severe congenital heart disease, Congenital anomalies, Cystic fibrosis, Cerebral palsy, Condition requiring use of nasogastric, gastric tube, or other alternative method of feeding, Undiagnosed conditions with significant impact on child's growth and development; Significant cardiac, hepatic, oncologic, inflammatory, or psychiatric disease.