Significant effect of gender on hamstring-to-quadriceps strength ratio and static balance in prepubescent children from 7 to 12 years of age

Background: A number of studies have reported lower muscular strength of the hamstring and the quadriceps and better postural control in female compared with male athletes. Whether those differences are innate and also exist in children and adolescents or are caused by training and participation in different sports is unknown. Hypothesis: Gender differences in hamstring and quadriceps muscular strength and static balance exist even before maturity. Study Design: Cross-sectional study; Level of evidence, 4. Methods: A total of 368 children between 7 and 12 years of age participated in the study. They performed isokinetic concentric hamstring and quadriceps muscle strength measurements at 60 and 240 deg/s and a static balance test using the KAT 2000. Data analysis consisted of independent-samples t tests and multiple regression analysis. Results: Gender had a significant effect on both the hamstring/quadriceps (HQ) ratios and static balance in children between 7 and 12 years of age. Except for the 7-year-old participants, boys showed significantly higher HQ ratios than the girls in every age group, indicating that the hamstring muscles in girls were relatively weak when compared with the quadriceps muscles. There was also a gender effect on the balance index with better balance in girls than boys. Conclusion: There is a significant gender difference in HQ ratios and static balance in children between 8 and 12 years of age. Because many children start their handball careers before the age of 10 years, the present findings indicate that prevention programs including hamstring strength training should be prescribed at an earlier age than recommended in previously published studies.