@inproceedings{IntziegianniCasselHainetal.2014,
  author    = {Intziegianni, Konstantina and Cassel, Michael and Hain, Gerrit and Fr{\"o}hlic, Katja and Mayer, Frank},
  title     = {Reliability of sonographic assessment of Achilles tendon cross-sectional area at rest and maximal voluntary contraction},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {46},
  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     = {47 -- 47},
  year      = {2014},
  language  = {en}
}
@inproceedings{RischCasselMesserschmidtetal.2014,
  author    = {Risch, Lucie and Cassel, Michael and Messerschmidt, Janin and Intziegianni, Konstantina and Mayer, Frank},
  title     = {Consistency and reliability of examining intratendinous blood flow in Achilles tendinopathy patients using doppler ultrasonography},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {46},
  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     = {46 -- 46},
  year      = {2014},
  language  = {en}
}
@inproceedings{ReschkeCasselIntziegiannietal.2014,
  author    = {Reschke, Antje and Cassel, Michael and Intziegianni, Konstantina and Mayer, Frank},
  title     = {Intra- and inter-rater reliability of sonographic cross-sectional area measurements in asymptomatic patella tendons},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {46},
  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     = {927 -- 928},
  year      = {2014},
  language  = {en}
}
@article{CasselRischIntziegiannietal.2018,
  author    = {Cassel, Michael and Risch, Lucie and Intziegianni, Konstantina and Mueller, Juliane and Stoll, Josefine and Brecht, Pia and Mayer, Frank},
  title     = {Incidence of achilles and patellar tendinopathy in adolescent elite athletes},
  series = {International journal of sports medicine},
  volume    = {39},
  journal   = {International journal of sports medicine},
  number    = {9},
  publisher = {Thieme},
  address   = {Stuttgart},
  issn      = {0172-4622},
  doi       = {10.1055/a-0633-9098},
  pages     = {726 -- 732},
  year      = {2018},
  abstract  = {The study investigated the incidence of Achilles and patellar tendinopathy in adolescent elite athletes and non-athletic controls. Furthermore, predictive and associated factors for tendinopathy development were analyzed. The prospective study consisted of two measurement days (M1/M2) with an interval of 3.2 +/- 0.9 years. 157 athletes (12.1 +/- 0.7 years) and 25 controls (13.3 +/- 0.6 years) without Achilles/patellar tendinopathy were included at Ml. Clinical and ultrasound examinations of both Achilles (AT) and patellar tendons (PT) were performed. Main outcome measures were incidence tendinopathy and structural intratendinous alterations (hypo-/hyperechogenicity, vascularization) at M2 [\%]. Incidence of Achilles tendinopathy was 1\% in athletes and 0\% in controls. Patellar tendinopathy was more frequent in athletes (13 \%)than in controls (4\%). Incidence of intratendinous alterations in ATs was 1-2\% in athletes and 0 \% in controls, whereas in PTs it was 4-6 \% in both groups (p >0.05). Intratendinous alterations at M2 were associated with patellar tendinopathy in athletes (p <= 0.01). Intratendinous alterations at M1, anthropometric data, training amount, sports or sex did not predict tendinopathy development (p>0.05). Incidence often dinopathy and intratendinous alterations in adolescent athletes is low in ATs and more common in PTs. Development of intratendinous alterations in PT is associated with tend in opathy. However, predictive factors could not be identified.},
  language  = {en}
}
@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{IntziegianniCasselRaufetal.2016,
  author    = {Intziegianni, Konstantina and Cassel, Michael and Rauf, S. and White, S. and Rector, Michael V. and Kaplick, Hannes and Wahmkow, Gunnar and Kratzenstein, S. and Mayer, Frank},
  title     = {Influence of Age and Pathology on Achilles Tendon Properties During a Single-leg Jump},
  series = {International journal of sports medicine},
  volume    = {37},
  journal   = {International journal of sports medicine},
  publisher = {Thieme},
  address   = {Stuttgart},
  issn      = {0172-4622},
  doi       = {10.1055/s-0042-108198},
  pages     = {973 -- 978},
  year      = {2016},
  abstract  = {Prevalence of Achilles tendinopathy increases with age leading to a weaker tendon with predisposition to rupture. Conclusive evidence of the influence of age and pathology on Achilles tendon (AT) properties remains limited, as previous studies are based on standardized isometric conditions. The study investigates the influence of age and pathology on AT properties during single-leg vertical jump (SLVJ). 10 children (C), 10 asymptomatic adults (A), and 10 tendinopathic patients (T) were included. AT elongation [mm] from rest to maximal displacement during a SLVJ on a force-plate was sonographically assessed. AT compliance [mm/N]) and strain [\%] was calculated by dividing elongation by peak ground reaction force [N] and length, respectively. One-way ANOVA followed by Bonferroni post-hoc correction (=0.05) were used to compare C with A and A with T. AT elongation (p=0.004), compliance (p=0.001), and strain were found to be statistically significant higher in C (27 +/- 3mm, 0.026 +/- 0.006[mm/N], 13 +/- 2\%) compared to A (21 +/- 4mm, 0.017 +/- 0.005[mm/N], 10 +/- 2\%). No statistically significant differences (p0.05) was found between A and T (25 +/- 5mm, 0.019 +/- 0.004[mm/N], 12 +/- 3\%). During SLVJ, tendon responded differently in regards to age and pathology with children having the most compliant AT. Higher compliance found in healthy tendons might be considered as a protective factor against load-related injuries.},
  language  = {en}
}
@article{CasselIntziegianniRischetal.2017,
  author    = {Cassel, Michael and Intziegianni, Konstantina and Risch, Lucie and M{\"u}ller, Steffen and Engel, Tilman and Mayer, Frank},
  title     = {Physiological Tendon Thickness Adaptation in Adolescent Elite Athletes},
  series = {Frontiers in physiology},
  volume    = {8},
  journal   = {Frontiers in physiology},
  publisher = {Frontiers},
  address   = {Lausanne},
  issn      = {1664-042X},
  doi       = {10.3389/fphys.2017.00795},
  pages     = {1 -- 8},
  year      = {2017},
  abstract  = {Increased Achilles (AT) and Patellar tendon (PT) thickness in adolescent athletes compared to non-athletes could be shown. However, it is unclear, if changes are of pathological or physiological origin due to training. The aim of this study was to determine physiological AT and PT thickness adaptation in adolescent elite athletes compared to non-athletes, considering sex and sport. In a longitudinal study design with two measurement days (M1/M2) within an interval of 3.2 ± 0.8 years, 131 healthy adolescent elite athletes (m/f: 90/41) out of 13 different sports and 24 recreationally active controls (m/f: 6/18) were included. Both ATs and PTs were measured at standardized reference points. Athletes were divided into 4 sport categories [ball (B), combat (C), endurance (E) and explosive strength sports (S)]. Descriptive analysis (mean ± SD) and statistical testing for group differences was performed (α = 0.05). AT thickness did not differ significantly between measurement days, neither in athletes (5.6 ± 0.7 mm/5.6 ± 0.7 mm) nor in controls (4.8 ± 0.4 mm/4.9 ± 0.5 mm, p > 0.05). For PTs, athletes presented increased thickness at M2 (M1: 3.5 ± 0.5 mm, M2: 3.8 ± 0.5 mm, p < 0.001). In general, males had thicker ATs and PTs than females (p < 0.05). Considering sex and sports, only male athletes from B, C, and S showed significant higher PT-thickness at M2 compared to controls (p ≤ 0.01). Sport-specific adaptation regarding tendon thickness in adolescent elite athletes can be detected in PTs among male athletes participating in certain sports with high repetitive jumping and strength components. Sonographic microstructural analysis might provide an enhanced insight into tendon material properties enabling the differentiation of sex and influence of different sports.},
  language  = {en}
}