TY  - JOUR
A1  - Wochatz, Monique
A1  - Rabe, Sophie
A1  - Wolter, Martin
A1  - Engel, Tilman
A1  - Mueller, Steffen
A1  - Mayer, Frank
T1  - Muscle activity of upper and lower trapezius and serratus anterior during unloaded and maximal loaded shoulder flexion and extension
JF  - International Biomechanics
N2  - Altered scapular muscle activity is mostly described under unloaded and submaximal loaded conditions in impingement patients. However, there is no clear evidence on muscle activity with respect to movement phases under maximum load in healthy subjects. Therefore, this study aimed to investigate scapular muscle activity under unloaded and maximum loaded isokinetic shoulder flexion and extension in regard to the movement phase. Fourteen adults performed unloaded (continuous passive motion [CPM]) as well as maximum loaded (concentric [CON], eccentric [ECC]) isokinetic shoulder flexion (Flex) and extension (Ext). Simultaneously, scapular muscle activity was measured by EMG. Root mean square was calculated for the whole ROM and four movement phases. Data were analyzed descriptively and by two-way repeated measures ANOVA. CPMFlex resulted in a linear increase of muscle activity for all muscles. Muscle activity during CONFlex and ECCFlex resulted in either constant activity levels or in an initial increase followed by a plateau in the second half of movement. CPMExt decreased with the progression of movement, whereas CONExt and ECCExt initially decreased and either levelled off or increased in the second half of movement. Scapular muscle activity of unloaded shoulder flexion and extension changed under maximum load showing increased activity levels and an altered pattern over the course of movement.
KW  - shoulder
KW  - scapular muscle activity
KW  - isokinetic testing
KW  - electromyography
Y1  - 2017
U6  - https://doi.org/https://doi.org/10.1080/23335432.2017.1364668
VL  - 4
IS  - 2
SP  - 68
EP  - 76
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Müller, Steffen
A1  - Mayer, Patrizia
A1  - Baur, Heiner
A1  - Mayer, Frank
T1  - Higher velocities in isokinetic dynamometry a pilot study of new test mode with active compensation of inertia
JF  - Isokinetics and exercise science : official journal of the European Isokinetic Society
N2  - Isokinetic dynamometry is a standard technique for strength testing and training. Nevertheless reliability and validity is limited due to inertia effects, especially for high velocities. Therefore in a first methodological approach the purpose was to evaluate a new isokinetic measurement mode including inertia compensation compared to a classic isokinetic measurement mode for single and multijoint movements at different velocities.
 Isokinetic maximum strength measurements were carried out in 26 healthy active subjects. Tests were performed using classic isokinetic and new isokinetic mode in random order. Maximum torque/force, maximum movement velocity and time for acceleration were calculated. For inter-instrument agreement Bland and Altman analysis, systematic and random error was quantified. Differences between both methods were assessed (ANOVA alpha = 0.05).
 Bland and Altman analysis showed the highest agreement between the two modes for strength and velocity measurements (bias: < +/- 1.1%; LOA: < 14.2%) in knee flexion/extension at slow isokinetic velocity (60 degrees/s). Least agreement (range: bias: -67.6% +/- 119.0%; LOA: 53.4% 69.3%) was observed for shoulder/arm test at high isokinetic velocity (360 degrees/s). The Isokin(new) mode showed higher maximum movement velocities (p < 0.05).
 For low isokinetic velocities the new mode agrees with the classic mode. Especially at high isokinetic velocities the new isokinetic mode shows relevant benefits coupled with a possible trade-off with the force/torque measurement. In conclusion, this study offers for the first time a comparison between the 'classical' and inertia-compensated isokinetic dynamometers indicating the advantages and disadvantages associated with each individual approach, particularly as they relate to medium or high velocities in testing and training.
KW  - Strength testing
KW  - concentric
KW  - validity
KW  - trunk
KW  - knee
KW  - shoulder
Y1  - 2011
U6  - https://doi.org/10.3233/IES-2011-0398
SN  - 0959-3020
VL  - 19
IS  - 2
SP  - 63
EP  - 70
PB  - IOS Press
CY  - Amsterdam
ER  -