Assessment of Quadriceps Muscle Strength and Thickness in Adolescents with Polycystic Ovary Syndrome: A Case-control and Longitudinal Follow-up Study

Objective: To date, muscle strength and thickness have not been investigated in adolescents with polycystic ovary syndrome (PCOS). This study aimed to investigate whether differences exist in these parameters between adolescents with PCOS and healthy controls. Additionally, we evaluated the effects of six months combined oral contraceptive (COC) treatment on quadriceps muscle characteristics.

Methods: The study included adolescents diagnosed with PCOS and healthy peers. Dynamometers were used to measure knee muscle and hand grip strengths, and ultrasound was used to measure quadriceps muscle thickness. In the PCOS group, all measurements were repeated after six months of COCs treatment.

Results: There were 20 participants in each of the PCOS and control groups. There were no significant differences between the groups in terms of age, weight, height, pubertal stage, Physical Activity Questionnaire scores, quadriceps muscle thickness, grip strength and isokinetic knee strengths at baseline. Within the PCOS group, significant increase were observed in weight, height, quadriceps strength and lipid levels after six months of treatment (all p<0.05). Subgroup analysis of COC treatments revealed significantly greater gains in quadriceps muscle strength among levonorgestrel users (n=6) compared to those using cyproterone acetate users (n=13).

Conclusion: Quadriceps muscle thickness and strength were comparable between adolescent with PCOS and controls, indicating no intrinsic muscular deficit. However, significantly greater improvements in quadriceps muscle strength were observed in those using levonorgestrel-containing COCs users compared to cyproterone acetate users. These findings suggest a potential role of progestin androgenicity in muscle strength. Further longitudinal studies with larger cohorts are warranted to validate these preliminary findings and to explore the impact of COCs with varying androgenic properties.