Research at the Wagner-Lab

Understanding the development of human movement and behavior is important to develop diagnostic tools and therapeutic interventions for people to live independently and comfortably. Of central importance is to understand the influence of acute and chronic pain on human predictive motor control.
Therefore, we investigate the physiological and patho-physiological development of human movement and behavior, e.g. motor impairments due to musculoskeletal pain and human cognitive and psychological conditions, and early-child development of first motor skills and abilities.
We analyze the influence of the mechanical properties of the musculoskeletal system on human stable movements, i.e. the selfstability.
To understand the emergence of movement patterns and behavior at the spinal cord, we investigate the complex neural structure within the spinal cord, in conjunction with selfstability and alpha-gamma-coactivation.
As a direct measurement of many neurophysiological connections is still experimentally unavailable, we develop computational models to investigate the complex neurophysiology of the spinal cord. These models are validated or falsified by kinematic and neurophysiological experiments.

Computational Modeling

NeuroBoB Sitting
© Wagner

We are developing various models of the musculoskeletal system, ranging from models describing single muscular contractions, antagonistic muscles acting at a single joint, up to complex 3D models of the human body NeuroBoB.
During the last two years we developed in cooperation with James Shippen, University Coventry, UK, a complex 3D-model of a human. The model can be used to perform mixed dynamical simulations, i.e. one can choose which joints will be driven by measured kinematics (inverse dynamics) and which joints will be driven by muscular forces (forward dynamics). These models can be used to describe and better understand the human dynamic system.
Recently we worked on a more physiological model of the muscles and we included a simple model of the sensory muscle spindles, i.e. Ia-afferences and II-afferences.
At the moment we improve an optimization algorithm to distribute the muscular activation to generate the required torques at a joint.

PIs: Heiko Wagner, Kim Boström
Co-operations: James Shippen, Coventry University, UK


© Wagner

In the year 1998 we introduced the idea of self-stabilization of the musculoskeletal system.
Based on that concept, the stability of different musculoskeletal systems in different situations were analyzed.
Based on these findings, we discussed self-stability to be a general principle in motor control and may be a driving force in human and animal evolution.
At the moment, this principle becomes highly important while we tried to make forward simultions with NeuroBoB.

Blickhan, R., Seyfarth, A., Geyer, H., Grimmer, S., Wagner, H., & Gunther, M. (2007). Intelligence by mechanics. Philos Transact a Math Phys Eng Sci, 365(1850), 199–220.
Giesl, P., & Wagner, H. (2007). Lyapunov function and the basin of attraction for a single-joint muscle-skeletal model. Journal of Mathematical Biology, 54(4), 453–464.
Giesl, P., Meisel, D., Scheurle, J., & Wagner, H. (2004). Stability analysis of the elbow with a load. Journal of Theoretical Biology, 228(1), 115–125.
Wagner, H., & Blickhan, R. (1999). Stabilizing function of skeletal muscles: an analytical investigation. J Theor Biol, 199(2), 163–179.
Wagner, H., & Blickhan, R. (2003). Stabilizing Function of Antagonistic Neuromusculoskeletal Systems - an Analytical Investigation. Biol Cybern, 89(1), 71–79.
Wagner, H., Giesl, P., & Blickhan, R. (2007). Musculoskeletal stabilization of the elbow - Complex or real. Journal of Mechanics in Medicine and Biology, 7(3), 275–296.

Computational Neuroscience

© Boström

To understand the function of the neural control system, we developed a computational model for the nociceptive and proprioceptive afferent information processing to understand the reorganization of the sensory cortex. Furthermore, we are developing computational model to describe the neural motor control of human movements. These artificial neural networks are based on the theory of reservoir computing.
At the moment we are working on a reformulation of the reafference principle of von Holst and Mittelstedt.
We started these kind of studies based on simple models with two and four neurons. These models were used to understand the postural reflexive responses, as well as the complex activation patterns of shank muscles during walking.

PIs: H. Wagner, K. Boström

Boström, K. J., de Lussanet, M. H. E., Weiss, T., Puta, C., & Wagner, H. (2014). A computational model unifies apparently contradictory findings concerning phantom pain. Scientific Reports, 4.
Boström, K. J., Wagner, H., Prieske, M., & de Lussanet Marc. (2013). Model for a flexible motor memory based on a self-active recurrent neural network. Human Movement Science, 32(5), 880–898.
Chong, S. Y., Wagner, H., & Wulf, A. (2012). Neural oscillators triggered by loading and hip orientation can generate activation patterns at the ankle during walking in humans. Medical & Biological Engineering & Computing, 50(9), 917–923.
Chong, S. Y., Wagner, H., & Wulf, A. (2013). Application of neural oscillators to study the effects of walking speed on rhythmic activations at the ankle. Theoretical Biology & Medical Modelling, 10(1), 9.
Wulf, A., Wagner, H., Wulf, T., Schinowski, D., Puta, C., Anders, C., & Chong, S. Y. (2012). Phasic bursting pattern of postural responses may reflect internal dynamics Simulation of trunk reflexes with a neural oscillator model. J Biomech, 45(15), 2645–2650.

Pain & Motor Control

© Wagner

Chronic back pain is an important scientific field in our group.
Since Heiko was in Jena, KIP, he is working on models and experimental setups to develop a diagnostic toolbox to prevent chronic pain.
Based on these works, and in cooperation with the PIs of a BMBF-grant, we made several studies to understand the altered sensorimotor control because of chronic pain.
These studies showed, e.g. delayed postural reflexes, and impaired visual perception of hurtful actions in patients with chronic low back pain and a body-part specific impairment in the visual recognition of actions in chronic pain patients.

PIs: H. Wagner, K. Boström, M. deLussanet
Cooperations: R. Blickhan, C. Puta, M. Lappe, T. Weiß

de Lussanet, M. H. E., Behrendt, F., Puta, C., Schulte, T. L., Lappe, M., Weiss, T., & Wagner, H. (2013). Impaired visual perception of hurtful actions in patients with chronic low back pain. Hum Mov Sci, 32(5), 938–953.
de Lussanet, M. H. E., Behrendt, F., Puta, C., Weiss, T., Lappe, M., Schulte, T. L., & Wagner, H. (2012). A body-part-specific impairment in the visual recognition of actions in chronic pain patients. Pain, 153(7), 1459–1466.
Liebetrau, A., Puta, C., Anders, C., de Lussanet, M. H. E., & Wagner, H. (2013). Influence of delayed muscle reflexes on spinal stability. Human Movement Science, 32(5), 954–970.
Liebetrau, A., Puta, C., Schinowski, D., Wulf, T., & Wagner, H. (2012). Is there a correlation between back pain and stability of the lumbar spine in pregnancy? : A model-based hypothesis. Schmerz, 26(1), 36–45.
Lükens, J., Boström, K. J., Puta, C., Schulte, T. L., & Wagner, H. (2015). Using ultrasound to assess the thickness of the transversus abdominis in a sling exercise. BMC Musculoskelet Disord, 16(1), 203.
Wagner, H. (2013). Tackling the challenges posed by the human dynamic system. Hum Mov Sci, 32(5), 877–879.
Wagner, H., Puta, C., Anders, C., Petrovitch, A., Schilling, N., & Scholle, H. C. (2009). Chronic unspecific back pain - From functional morphology to prevention. Manuelle Medizin, 47(1), 39–51.

Handcycle settings and their effects on efficiency and propulsion technique

The use of a wheelchair is mechanically inefficient and hand-rim propulsion can often contribute to overuse injuries around the shoulder joint, due to its repetitive characteristic. Since the eighties of the last century, handcycling has become an important alternative to hand-rim propulsion in wheelchair-dependent individuals, since the capacity to deliver power is limited in this group. In daily living, the add-on handcycle is often used outdoors. The add-on handcycle consists of a crank system, which can be attached to the wheelchair in front of the user, and made handcycling widely available. It usually has multiple gears, to enable cycling in different cadences and at different speeds so that longer distances can be reached. The earlier handcycles were based on bicycle technology, and therefore, had an asynchronous crank mode. This crank mode is still seen in non-Western countries nowadays. However, in the Western countries, the handcycles are in a synchronous crank mode (Dallmeijer, 2004; Hettinga, 2010).
The aim of the promotion is to investigate the effects of different handcycle settings on the efficiency and propulsion technique during sub-maximal exercise. In order to do so, gear, imposed resistance and crank mode will be altered and the kinetics, kinematics, physiological parameters and muscle activation will be measured. From this data, efficiency can be calculated and dynamical analyses can be performed to understand the underlying mechanisms of handcycling.
During the last two months, Cassandra visited Groningen twice. The first time she ordered her experimental data and looked into them. She has made first steps into comparing the synchronous and asynchronous conditions of her hand cycling experiments. During the second visit she met Yves VanLandewijck (KU Leuven) who is member of the IPC (international paralympic committee). They also looked into the mysterious finding that the power is different even if all other settings are the same.
Currently Cassandra revises her first paper.
Over the coming months she will visit the ESB (Sevilla) and Science & Cycling (Düsseldorf), and will further process her data. Cassandra will perform het teaching duties.

PIs: Cassandra KraaijenbrinkK, H. Wagner
Cooperations (with pics): L. van der Woude, R. Vegter

Dallmeijer AJ, Zentgraaff ID, Zijp NI, van der Woude LH. Submaximal physical strain and peak performance in handcycling versus handrim wheelchair propulsion. Spinal Cord. 2004;42(2):91-98.
Hettinga FJ, Valent L, Groen W, van Drongelen S, de Groot S, van der Woude LH. Hand-cycling: An active form of wheeled mobility, recreation, and sports. Phys Med Rehabil Clin N Am. 2010;21(1):127-140.


© Kim Bostroem

In traffic accidents have become a major health problem. Severe injuries occur during accidents in the high-velocity range, but also traffic accidents in the low-velocity range have become an important economical and health-related factor. We made oblique frontal crash-tests to simultaneously study the motion of the occupants and of the vehicle. With an experimental setup to capture  the motion of the occupants and of the vehicle, as well as the analysis of the measured data, which is used for computational modelling. As for the latter, a novel 3D computational model NeuroBoB of the human body has been implemented, which allows the calculation of muscle activities and biomechanical loads from measured kinematic data.

PIs: H. Wagner, K. Boström, W. Kalthoff
Cooperations: W. Castro, M. Becke, M. Hein, N. Schilling