TY  - JOUR
A1  - Heinke, Lars N.
A1  - Knicker, Axel J.
A1  - Albracht, Kirsten
T1  - Test-retest reliability of the internal shoulder rotator muscles' stretch reflex in healthy men
JF  - Journal of Electromyography and Kinesiology
N2  - Until now the reproducibility of the short latency stretch reflex of the internal rotator muscles of the glenohumeral joint has not been identified. Twenty-three healthy male participants performed three sets of external shoulder rotation stretches with various pre-activation levels on two different dates of measurement to assess test-retest reliability. All stretches were applied with a dynamometer acceleration of 104°/s2 and a velocity of 150°/s. Electromyographical response was measured via surface EMG. Reflex latencies showed a pre-activation effect (ƞ2 = 0,355). ICC ranged from 0,735 to 0,909 indicating an overall “good” relative reliability. SRD 95% lay between ±7,0 to ±12,3 ms.. The reflex gain showed overall poor test-retest reproducibility. The chosen methodological approach presented a suitable test protocol for shoulder muscles stretch reflex latency evaluation. A proof-of-concept study to validate the presented methodical approach in shoulder involvement including subjects with clinically relevant conditions is recommended.
KW  - stretch reflex
KW  - shoulder
KW  - test-retest reliability
KW  - intraclass correlation coefficient
KW  - standard error of measurement
Y1  - 2021
U6  - http://dx.doi.org/10.1016/j.jelekin.2021.102611
SN  - 1050-6411
VL  - 62
IS  - Article 102611
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Heinke, Lars N.
A1  - Knicker, Axel J.
A1  - Albracht, Kirsten
T1  - Increased shoulder muscle stretch reflex elicitability in supine subject posture
JF  - Isokinetics and Exercise Science
N2  - BACKGROUND: Muscle stretch reflexes are widely used to examine neural muscle function. The knowledge of reflex response in muscles crossing the shoulder is limited. OBJECTIVE: To quantify reflex modulation according to various subject postures and different procedures of muscle pre-activation steering. METHODS: Thirteen healthy male participants performed two sets of external shoulder rotation stretches in various positions and with different procedures of muscle pre-activation steering on an isokinetic dynamometer over a range of two different pre-activation levels. All stretches were applied with a dynamometer acceleration of 104∘/s2 and a velocity of 150∘/s. Electromyographical response was measured via sEMG. RESULTS: Consistent reflexive response was observed in all tested muscles in all experimental conditions. The reflex elicitation rate revealed a significant muscle main effect (F (5,288) = 2.358, ρ= 0.040; η2= 0.039; f= 0.637) and a significant test condition main effect (F (1,288) = 5.884, ρ= 0.016; η2= 0.020; f= 0.143). Reflex latency revealed a significant muscle pre-activation level main effect (F (1,274) = 5.008, ρ= 0.026; η2= 0.018; f= 0.469). CONCLUSION: Muscular reflexive response was more consistent in the primary internal rotators of the shoulder. Supine posture in combination with visual feedback of muscle pre-activation level enhanced the reflex elicitation rate.
Y1  - 2020
U6  - http://dx.doi.org/10.3233/IES-192219
SN  - 1878-5913
VL  - 28
IS  - 2
SP  - 139
EP  - 146
PB  - IOS Press
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Heinke, Lars N.
A1  - Knicker, Axel J.
A1  - Albracht, Kirsten
T1  - Evaluation of passively induced shoulder stretch reflex using an isokinetic dynamometer in male overhead athletes
JF  - Isokinetics and Exercise Science
N2  - BACKGROUND: Muscle stretch reflexes are widely considered to beneficially influence joint stability and power generation in the lower limbs. While in the upper limbs and especially in the muscles surrounding the shoulder joint such evidence is lacking. OBJECTIVE: To quantify the electromyographical response in the muscles crossing the shoulder of specifically trained overhead athletes to an anterior perturbation force. METHODS: Twenty healthy male participants performed six sets of different external shoulder rotation stretches on an isokinetic dynamometer over a range of amplitudes and muscle pre-activation moment levels. All stretches were applied with a dynamometer acceleration of 10,000∘/s2 and a velocity of 150∘/s. Electromyographical response was measured via sEMG. RESULTS: Consistent reflexes were not observed in all experimental conditions. The reflex latencies revealed a significant muscle main effect (F (2,228) = 99.31, p< 0.001; η2= 0.466; f= 0.934) and a pre-activation main effect (F (1,228) = 142.21, p< 0.001; η2= 0.384; f= 1.418). The stretch reflex amplitude yielded a significant pre-activation main effect (F (1,222) = 470.373, p< 0.001; η2= 0.679; f= 1.454). CONCLUSION: Short latency muscle reflexes showed a tendency to an anterior to posterior muscle recruitment whereby the main internal rotator muscles of the shoulder revealed the most consistent results.
Y1  - 2018
U6  - http://dx.doi.org/10.3233/IES-184111
SN  - 1878-5913
VL  - 26
IS  - 4
SP  - 265
EP  - 274
PB  - IOS Press
CY  - Amsterdam
ER  -