To examine the effect of first season ballet classes in the community on the thoracic kyphosis (TK), lumbar lordosis (LL), hip external rotation (ER) and joint flexibility in young girls.Longitudinal single blinded cohort control study.Institutional.30 girls aged 6–9, recruited from the same primary school were divided equally into 2 groups: a group bi-weekly community ballet class and a sedentary control group.All girls were assessed prior to ballet classes (t 0 ), at the conclusion (t 1 ) (6 months), and approximately one year later (t fu ).Beighton score for joint hyper-flexibility, peak of TK and LL, range of hip ER, ratio TK/LL, and individual’s height, weight and BMI.LL at t1 became greater in the ballet girls’ group (23.7°± 6) as opposed to the controls (19.5°±3.9) due to a decrease in LL in the controls from t0 to t1 (mean difference = −16.5°) (cut-off score = 3.45°) (p < 0.05). TK decreased from t0 to t1 in the ballet girls’ group (mean difference = −26.1°) and controls (mean difference = −31.3°) (cut-off score = 4.85°) (p < 0.05). Left hip ER decreased only in the controls from t0 to t1 (mean difference = −13.8°) (cut-off score = 5.43°) (p < 0.05). Beighton score at tfu was greater in the ballet girls’ group (6.1 ± 2.3) as opposed to the controls (4.4 ± 1.5) (p < 0.05).First season ballet classes for young girls in the community can be associated with relatively greater LL, and left hip ER and joint hyper-flexibility.