TY  - JOUR
A1  - Intziegianni, Konstantina
A1  - Cassel, Michael
A1  - König, Niklas
A1  - Müller, Steffen
A1  - Fröhlich, Katja
A1  - Mayer, Frank
T1  - Ultrasonography for the assessment of the structural properties of the Achilles tendon in asymptomatic individuals: An intra-rater reproducibility study
JF  - Isokinetics and exercise science : official journal of the European Isokinetic Society
N2  - 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.
KW  - Ultrasonography
KW  - Achilles tendon
KW  - reproducibility
KW  - isokinetic
Y1  - 2015
U6  - https://doi.org/10.3233/IES-150586
SN  - 0959-3020
SN  - 1878-5913
VL  - 23
IS  - 4
SP  - 263
EP  - 270
PB  - IOS Press
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Rector, Michael V.
A1  - Intziegianni, Konstantina
A1  - Müller, Steffen
A1  - Mayer, Frank
A1  - Cassel, Michael
T1  - Reproducibility of an ankle joint rotation correction method for assessment of Achilles tendon elongation
JF  - Isokinetics and exercise science : official journal of the European Isokinetic Society
N2  - BACKGROUND: The Achilles tendon (AT) requires optimal material and mechanical properties to function properly. Calculation of these properties depends on accurate measurement of input parameters (i.e. tendon elongation). However, the measurement of AT elongation with ultrasound during maximum voluntary isometric contraction (MVIC) is overestimated by ankle joint rotation (AJR). Methods to correct the influence of this rotation on AT elongation exist, yet their reproducibility in clinical settings is unknown. OBJECTIVE: To evaluate the test-retest reproducibility of AT elongation during MVIC after AJR correction. METHODS: Ten participants attended test and retest measurements where they performed plantar-flexion MVIC on a dynamometer. Simultaneously, ultrasound recorded AT elongation as the displacement of the medial gastrocnemius-myotendinous junction, while an electrogoniometer measured AJR. The ankle was then passively rotated to the AJR achieved during MVIC and AT elongation again determined. Elongation was corrected by subtracting this passive AT elongation from the total AT elongation during MVIC. Reproducibility was evaluated using ICC (2.1), test-retest variability (TRV, %), Bland-Altman analyses (Bias +/- LoA [1.96*SD]) and standard error of the measurement (SEM). RESULTS: Corrected AT elongation reproducibility exhibited an ICC = 0.79, SEM = 0.2 cm and TRV = 20 +/- 19%. Bias +/- LoA were determined to be 0.0 +/- 0.8 cm. CONCLUSIONS: Using this ultrasound and electrogoniometer-based method, corrected AT elongation can be assessed reproducibly.
KW  - Ultrasonography
KW  - Achilles tendon
KW  - reproducibility
KW  - isokinetic
KW  - ankle joint rotation
Y1  - 2017
U6  - https://doi.org/10.3233/IES-160644
SN  - 0959-3020
SN  - 1878-5913
VL  - 25
IS  - 1
SP  - 47
EP  - 52
PB  - IOS Press
CY  - Amsterdam
ER  -