Participation In A Community-based Running Program Is Associated With Higher Hip Bmc In Young Girls

Abstract

Girls on the Run (GOTR) is a community-based running program that encourages social, mental, emotional and physical development in young girls through the process of training for a 5k running event. Previous reports have shown that GOTR has positive effects on self esteem and dietary behaviors; whether GOTR influences physiological outcomes is unknown. PURPOSE: To determine if participation in GOTR is associated with positive skeletal development in 8-12 year-old girls. METHODS: Girls (n=31; 9.8±1.4 yrs) were recruited from seven different GOTR Willamette Valley sites to form the intervention group. Girls who did not participate in GOTR or other organized physical activity formed the control group (n=11; 9.6±0.73 yrs). All girls completed a standard health history questionnaire at baseline. Weight, height, and time spent in moderate to vigorous physical activity (MVPA) were measured at baseline, 3, 6, and 9 months. MVPA was measured by accelerometry over a 7-day period at each time point. Bone mineral content (BMC (g/cm2); assessed using DXA) and nutrient intakes (assessed using the Youth Adolescent Food Frequency Questionnaire) were evaluated at baseline and 9-months. To determine baseline differences between groups in BMC outcomes, ANCOVA was used adjusting for age, height, weight, maturation status (years from peak ht. velocity), nutrient intakes and MVPA. The ANCOVA was repeated at 9-months adding initial BMC values to determine differences in BMC outcomes between groups at follow-up. RESULTS: At baseline GOTR participants had higher BMC at the femoral neck (FN) site compared to controls (mean + SE; 2.68 + 0.06 vs. 2.33 + 0.12; p=0.02); there were no baseline differences at any other bone site (p>0.05). At 9-months, GOTR participants had higher FN BMC (p=0.048) and higher trochanteric BMC (p=0.039) compared to controls after adjusting for growth, diet, activity and initial BMC values. There were no group differences at any other bone site (P>0.05). CONCLUSIONS: After adjusting for growth, maturation, diet, MVPA, and initial BMC values, we found that GOTR participants exhibited higher FN and trochanteric BMC compared to controls. Thus there appears to be a positive association between participation in GOTR and skeletal development at the hip in growing girls.