@article{KellisEllinoudisIntziegiannietal.2020,
  author    = {Kellis, Eleftherios and Ellinoudis, Athanasios and Intziegianni, Konstantina and Kofotolis, Nikolaos},
  title     = {Muscle thickness during core stability exercises in children and adults},
  series = {Journal of human kinetics},
  volume    = {71},
  journal   = {Journal of human kinetics},
  number    = {1},
  publisher = {Academy of Physical Education},
  address   = {Katowice},
  issn      = {1640-5544},
  doi       = {10.2478/hukin-2019-0079},
  pages     = {131 -- 144},
  year      = {2020},
  abstract  = {Core stability exercises are regular part of exercise programs for asymptomatic individuals across ages. The purpose of this study was to examine deep abdominal and multifidus muscle thickness in children and adults and to determine reliability of the rehabilitative ultrasound (RUSI) imaging. Transversus abdominis and lumbar multifidus thickness at rest and during core stability exercise were examined in pre-pubertal children (N = 23), adolescents (N = 20), young adults (N = 21) and middle-aged adults (N = 22). Thirty-nine participants were re-tested one week after to establish reliability. Muscle thickness at rest was lower in children and adolescents compared with young and middle-aged adults (p < 0.008). Young adults displayed the highest relative transversus abdominis thickness upon contraction (p < 0.008). Lumbar multfidus contraction thickness was greater in young-adults than middle-aged adults and prepubertal children (p < 0.008), but it was similar between young-adults and adolescents (p > 0.008). Reliability was high for both muscles (ICC3,3 = 0.76 - 0.99). The age-related differences in muscle thickness indicate that core stability exercises may be beneficial for children and middle-aged adults.},
  language  = {en}
}
@article{KoenigCasselIntziegiannietal.2014,
  author    = {K{\"o}nig, Niklas and Cassel, Michael and Intziegianni, Konstantina and Mayer, Frank},
  title     = {Inter-rater reliability and measurement error of sonographic muscle architecture assessments},
  series = {Journal of ultrasound in medicine},
  volume    = {33},
  journal   = {Journal of ultrasound in medicine},
  number    = {5},
  publisher = {American Institute of Ultrasound in Medicine},
  address   = {Laurel},
  issn      = {0278-4297},
  doi       = {10.7863/ultra.33.5.769},
  pages     = {769 -- 777},
  year      = {2014},
  abstract  = {Objectives-Sonography of muscle architecture provides physicians and researchers with information about muscle function and muscle-related disorders. Inter-rater reliability is a crucial parameter in daily clinical routines. The aim of this study was to assess the inter-rater reliability of sonographic muscle architecture assessments and quantification of errors that arise from inconsistent probe positioning and image interpretation. Results-Inter-rater reliability was good overall (ICC, 0.77-0.90; IRV, 9.0\%-13.4\%; bias LoA, 0.2 +/- 0.2-1.7 +/- 3.0). Superior and inferior pennation angles showed high systematic bias and LoA in all setups, ranging from 2.0 degrees +/- 2.2 degrees to 3.4 degrees +/- 4.1 degrees. The highest IRV was found for muscle thickness (13.4\%). "When the probe position was standardized, the SEM for muscle thickness decreased from 0.1 to 0.05 cm. Conclusions-Sonographic examination of muscle architecture of the medial gastrocnemius has good to high reliability. In contrast to pennation angle measurements, length measurements can be improved by standardization of the probe position.},
  language  = {en}
}