@article{KellisEllinoudisIntziegianni2017,
  author    = {Kellis, Eleftherios and Ellinoudis, Athanasios and Intziegianni, Konstantina},
  title     = {Reliability of sonographic assessment of biceps femoris distal tendon strain during passive stretching},
  series = {Ultrasound in Medicine \& Biology},
  volume    = {43},
  journal   = {Ultrasound in Medicine \& Biology},
  publisher = {Elsevier},
  address   = {New York},
  issn      = {0301-5629},
  doi       = {10.1016/j.ultrasmedbio.2017.04.018},
  pages     = {1769 -- 1779},
  year      = {2017},
  abstract  = {The purpose of this study was to determine the intra-rater, inter-examiner and inter-observer reliability of biceps femoris long head (BFlh) tendon strain using ultrasound imaging. Nineteen patients (age: 20.4 +/- 0.35 y) were tested twice with a 1-wk interval. Each session included passive stretching from three different hip positions. Tests were performed independently by two examiners while BFlh tendon displacement (mm) and strain (\%) were manually extracted from ultrasound video footages by two observers. Intra-rater comparisons revealed an intra-class correlation coefficient (ICC2,1) range of 0.87 to 0.98 and a variability less than 4.74\%. Interexaminer comparisons revealed an ICC2,1 range of 0.83 to 0.99 and less than 4.69\% variability. Inter-observer ICCs ranged from 0.93 to 0.97 with variability less than 4.89\%. Using a well-defined scanning protocol, two experienced examiners attained high levels of intra-rater agreement, with similarly excellent results for inter-rater and inter-observer reliability for BFlh tendon displacement and strain. (E-mail: ekellis@phed-sr.auth.gr) (C) 2017 World Federation for Ultrasound in Medicine \& Biology.},
  language  = {en}
}
@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}
}