title: Voice training and changing weight--are they reflected in speaking fundamental frequency, voice range, and pitch breaks of 13-year-old girls? A longitudinal study.
abstract: OBJECTIVE
  Assessment of the voice-change progress of 20 girls (12-13 years) over 1 year by observing changes in speaking fundamental frequency (SFo), voice range, and register pitch breaks in the context of weight, height, voice training, and self-perception.
  
  
  METHODS
  One-year longitudinal collective case study.
  
  
  METHODS
  Twenty girls were recorded at the beginning and end of a year; nine girls were recorded another three times. SFo, vocal range, and characteristics were analyzed and interactions between these data assessed against weight and height to indicate pubertal development, and to test the hypothesis that changes in weight, height, SFo, and pitch breaks were related. Effects of training and the girls' self-perception of their voice use were also assessed.
  
  
  RESULTS
  Vocal characteristics changed as the girls passed through different weight ranges. During 47.5-52.4 kg (called band 2) and 52.4-57.5 kg (band 3), there was progressive contraction of vocal range and in some girls a slight rise in SFo between recording times 1 and 5. Both high- and low-pitch breaks were present in 45% of girls' voices. Girls in band 4 (<57.5 kg) had an increased vocal range, and pitch breaks in vocal-range areas that indicated the development of adult vocal registers. In this study, voice-trained girls were heavier, had higher SFo, used wider speech-range inflection, had a higher vocal range, and greater voice-use confidence; all girls lost confidence in their voice use over the year.
  
  
  CONCLUSIONS
  In this longitudinal study of twenty 13-year-old girls, voice changes in SFo, vocal range, and pitch-break frequency were synchronous with certain weight ranges. Girls with training registered higher maximum phonational frequency and were more confident in their voice use than girls without training.
authors.affiliation: Australian Centre for Applied Research in Music Performance, University of Sydney, New South Wales, Australia. ewil3297@uni.sydney.edu.au
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Willis
authors.forename: Dianna T
authors.initials: DT
authors.lastname: Kenny
mesh_terms: D000293:Adolescent; D041923:Adolescent Development; D001827:Body Height / Q000502:physiology; D001835:Body Weight / Q000502:physiology*; D002648:Child; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D009146:Music; D012649:Self Concept; D014827:Vocal Cords / Q000254:growth & development* / Q000502:physiology*; D014833:Voice Quality / Q000502:physiology*; D014834:Voice Training