@article{IntziegianniCasselKoenigetal.2015,
  author    = {Intziegianni, Konstantina and Cassel, Michael and K{\"o}nig, Niklas and M{\"u}ller, Steffen and Fr{\"o}hlich, Katja and Mayer, Frank},
  title     = {Ultrasonography for the assessment of the structural properties of the Achilles tendon in asymptomatic individuals: An intra-rater reproducibility study},
  series = {Isokinetics and exercise science : official journal of the European Isokinetic Society},
  volume    = {23},
  journal   = {Isokinetics and exercise science : official journal of the European Isokinetic Society},
  number    = {4},
  publisher = {IOS Press},
  address   = {Amsterdam},
  issn      = {0959-3020},
  doi       = {10.3233/IES-150586},
  pages     = {263 -- 270},
  year      = {2015},
  abstract  = {BACKGROUND: Reproducible measurements of tendon structural properties are a prerequisite for accurate diagnosis of tendon disorders and for determination of their mechanical properties. Despite the widely used application of Ultrasonography (US) in musculoskeletal assessment, its operator dependency and lack of standardization influences the consistency of the measurement. OBJECTIVE: To evaluate the intra-rater reproducibility of a standardized US method assessing the structural properties of the Achilles tendon (AT). METHODS: Sixteen asymptomatic participants were positioned prone on an isokinetic dynamometer with the knee extended and ankle at 90. flexion. US was used to assess AT-length, cross-sectional area (CSA), and AT-elongation during isometric plantarflexion contraction. The intra-rater reproducibility was assessed by ICC (2.1), Test-Retest Variability (TRV, \%), Bland-Altman analyses (Bias +/- LoA [1.96*SD]), and Standard-Error of Measurement (SEM). RESULTS: Measurements of AT-length demonstrated an ICC of 0.93, TRV of 4.5 +/- 3.9\%, Bias +/- LoA of -2.8 +/- 25.0 mm and SEM of 6.6 mm. AT-CSA showed an ICC of 0.79, TRV of 8.7 +/- 9.6\%, Bias +/- LoA of 1.7 +/- 19.4 mm(2) and SEM of 5.3 mm(2). AT-elongation revealed an ICC of 0.92, TRV of 12.9 +/- 8.9\%, Bias +/- LoA of 0.3 +/- 5.7 mm and SEM of 1.5 mm. CONCLUSIONS: The presented methodology allows a reproducible assessment of Achilles tendon structural properties when performed by a single rater.},
  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}
}
@inproceedings{ReschkeWolterSchoepflinetal.2012,
  author    = {Reschke, Antje and Wolter, Martin and Sch{\"o}pflin, Marlene and K{\"o}nig, Niklas and Mayer, Frank and Baur, Heiner},
  title     = {The effect of foot orthoses on peroneal H-reflex in treadmill walking a pilot study},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {44},
  booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {0195-9131},
  pages     = {943 -- 943},
  year      = {2012},
  language  = {en}
}
@inproceedings{KoenigStollMayeretal.2012,
  author    = {K{\"o}nig, Niklas and Stoll, Andreas and Mayer, Frank and Baur, Heiner},
  title     = {Intrasession reliability of insole in-shoe plantar pressure measurements in different foot areas},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {44},
  booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {0195-9131},
  pages     = {941 -- 941},
  year      = {2012},
  language  = {en}
}
@article{KoenigReschkeWolteretal.2013,
  author    = {K{\"o}nig, Niklas and Reschke, Antje and Wolter, Martin and M{\"u}ller, Steffen and Mayer, Frank and Baur, Heiner},
  title     = {Plantar pressure trigger for reliable nerve stimulus application during dynamic H-reflex measurements},
  series = {Gait \& posture},
  volume    = {37},
  journal   = {Gait \& posture},
  number    = {4},
  publisher = {Elsevier},
  address   = {Clare},
  issn      = {0966-6362},
  doi       = {10.1016/j.gaitpost.2012.09.021},
  pages     = {637 -- 639},
  year      = {2013},
  abstract  = {In dynamic H-reflex measurements, the standardisation of the nerve stimulation to the gait cycle is crucial to avoid misinterpretation due to altered pre-synaptic inhibition. In this pilot study, a plantar pressure sole was used to trigger the stimulation of the tibialis nerve with respect to the gait cycle. Consequently, the intersession reliability of the soleus muscle H-reflex during treadmill walking was investigated. Seven young participants performed walking trials on a treadmill at 5 km/h. The stimulating electrode was placed on the tibial nerve in the popliteal fossa. An EMG was recorded from the soleus muscle. To synchronize the stimulus to the gait cycle, initial heel strike was detected with a plantar pressure sole. Maximum H-reflex amplitude and M-wave amplitude were obtained and the Hmax/Mmax ratio was calculated. Data reveals excellent reliability, ICC = 0.89. Test-retest variability was 13.0\% (+/- 11.8). The Bland-Altman analysis showed a systematic error of 2.4\%. The plantar pressure sole was capable of triggering the stimulation of the tibialis nerve in a reliable way and offers a simple technique for the evaluation of reflex activity during walking.},
  language  = {en}
}
@inproceedings{WochatzCasselKoenigetal.2013,
  author    = {Wochatz, Monique and Cassel, Michael and K{\"o}nig, Niklas and Fr{\"o}hlich, Katja and Mayer, Frank},
  title     = {Intra- and inter-observer variability of a retrospective analysis of achilles tendon ultrasound scans},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {45},
  booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  number    = {5},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {0195-9131},
  pages     = {239 -- 239},
  year      = {2013},
  language  = {en}
}
@inproceedings{IntziegianniCasselKoenigetal.2013,
  author    = {Intziegianni, Konstantina and Cassel, Michael and K{\"o}nig, Niklas and Mayer, Frank},
  title     = {Reliability of variables defining mechanical and material properties of the achilles tendon},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {45},
  booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  number    = {5},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {0195-9131},
  pages     = {238 -- 239},
  year      = {2013},
  language  = {en}
}