The association between menarche, intensity of training and passive joint ROM in young pre-professional female dancers: A longitudinal follow-up study.
OBJECTIVES
To determine the association between the status of menarche (yes/no), the intensity of training and the potential to improve passive joint range of motion (ROM) over a 12-month period of dance training.


DESIGN
Prospective cohort study.


SETTING
Dance studio.


PARTICIPANTS
Fifty-nine female dancers aged 12.8 ± 0.5.


MAIN OUTCOME MEASURES
The dancers were asked about their dance intensity and screened for anthropometric parameters and passive joint ROM in Grades 7 and 8.


RESULTS
Along the 12 months of dance training, we found significantly increased ankle-foot en-pointe, hip abduction, and hip external rotation (ER); significantly decreased hip internal rotation (IR); and significant increased hip ER:IR ratio. In Grade 7, 26 dancers (44.1%) reached menarche (Yes menarche); in Grade 8 an additional 23 dancers (39.0%) reached menarche (No/Yes menarche); and 10 dancers (16.9%) had not reached menarche (No menarche). MANOVA (mixed models) with repeated measures to compare joint ROM between the three menarche groups (Yes; No/Yes; No), with h/week dance practice as a co-variant, showed that hip ER, ankle-foot en-pointe, and ER:IR were significantly correlated with h/week in all three menarche groups.


CONCLUSIONS
Most passive joint ROM can be improved over 12 months of dancing around the age onset of menarche. H/week of dance practice is a main factor contributing to improved hip ER, ankle-foot en-pointe and ER/IR ratio.
['Steinberg|Nili|N|', 'Tenenbaum|Shay|S|', 'Stern|Myriam|M|', 'Zeev|Aviva|A|', 'Siev-Ner|Itzhak|I|']
D002648:Child D003615:Dancing D005260:Female D005500:Follow-Up Studies D006801:Humans D008137:Longitudinal Studies D035002:Lower Extremity D008572:Menarche D016059:Range of Motion, Articular D012399:Rotation
Passive joint ROM Dancer Dance intensity Age onset of menarche