TY  - JOUR
A1  - Quittmann, Oliver J.
A1  - Meskemper, Joshua
A1  - Abel, Thomas
A1  - Albracht, Kirsten
A1  - Foitschik, Tina
A1  - Rojas-Vega, Sandra
A1  - Strüder, Heiko K.
T1  - Kinematics and kinetics of handcycling propulsion at increasing workloads in able-bodied subjects
JF  - Sports Engineereing
N2  - In Paralympic sports, biomechanical optimisation of movements and equipment seems to be promising for improving performance. In handcycling, information about the biomechanics of this sport is mainly provided by case studies. The aim of the current study was (1) to examine changes in handcycling propulsion kinematics and kinetics due to increasing workloads and (2) identify parameters that are associated with peak aerobic performance. Twelve non-disabled male competitive triathletes without handcycling experience voluntarily participated in the study. They performed an initial familiarisation protocol and incremental step test until exhaustion in a recumbent racing handcycle that was attached to an ergometer. During the incremental test, tangential crank kinetics, 3D joint kinematics, blood lactate and ratings of perceived exertion (local and global) were identified. As a performance criterion, the maximal power output during the step test (Pmax) was calculated and correlated with biomechanical parameters. For higher workloads, an increase in crank torque was observed that was even more pronounced in the pull phase than in the push phase. Furthermore, participants showed an increase in shoulder internal rotation and abduction and a decrease in elbow flexion and retroversion. These changes were negatively correlated with performance. At high workloads, it seems that power output is more limited by the transition from pull to push phase than at low workloads. It is suggested that successful athletes demonstrate small alterations of their kinematic profile due to increasing workloads. Future studies should replicate and expand the test spectrum (sprint and continuous loads) as well as use methods like surface electromyography (sEMG) with elite handcyclists.
Y1  - 2018
U6  - http://dx.doi.org/10.1007/s12283-018-0269-y
SN  - 1460-2687
VL  - 21
IS  - 21
SP  - 283
EP  - 294
PB  - Springer Nature
CY  - Cham
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  - 
TY  - CHAP
A1  - Richter, Charlotte
A1  - Braunstein, Bjoern
A1  - Stäudle, Benjamin
A1  - Attias, Julia
A1  - Suess, Alexander
A1  - Weber, T.
A1  - Rittweger, Joern
A1  - Green, David A.
A1  - Albracht, Kirsten
T1  - In vivo fascicle length of the gastrocnemius muscle during walking in simulated martian gravity using two different body weight support devices
T2  - 23rd Annual Congress of the European College of Sport Science, Dublin, Irland
Y1  - 2018
ER  - 
TY  - JOUR
A1  - Rittweger, Jörn
A1  - Albracht, Kirsten
A1  - Flück, Martin
A1  - Ruoss, Severin
A1  - Brocca, Lorenza
A1  - Longa, Emanuela
A1  - Moriggi, Manuela
A1  - Seynnes, Olivier
A1  - Di Giulio, Irene
A1  - Tenori, Leonardo
A1  - Vignoli, Alessia
A1  - Capri, Miriam
A1  - Gelfi, Cecilia
A1  - Luchinat, Claudio
A1  - Franceschi, Claudio
A1  - Bottinelli, Roberto
A1  - Cerretelli, Paolo
A1  - Narici, Marco
T1  - Sarcolab pilot study into skeletal muscle’s adaptation to longterm spaceflight
JF  - npj Microgravity
Y1  - 2018
U6  - http://dx.doi.org/10.1038/s41526-018-0052-1
SN  - 2373-8065
VL  - 4
IS  - 1
SP  - 1
EP  - 9
PB  - Nature Portfolio
ER  -