The ISEK Congress will include a series of Symposia sessions which will be scheduled throughout the conference from July 12-14, 2020. Please see the various descriptions below.
S1. Neuromuscular adaptation to pain during movement
Presenters: Jean-Sebastien Roy, Université Laval; Hugo Massé-Alarie, Université Laval; Michael Hunt, University of British Columbia; Natalie Collins, University of Queensland; Kylie Tucker, University of Queensland
Movement control relies on central processing of sensory information and selection of appropriate motor strategies; both can be impacted by pain. This symposium aims at debating how pain can perturb movement from biomechanical and neural perspectives.
S2. Motor Unit Firing Characteristics and Their Relationship to Muscle Dynamics
Presenters: Andrew G Cresswell, The University of Queensland; Eduardo Martinez-Valdes, University of Birmingham; Anderson Oliveira, Aalborg Univeritet; Trent Herda, The University of Kansas
While many studies have examined motor unit firing properties in humans during voluntary contractions, muscle dynamics are often overlooked, or are difficult to assess. This symposium will consist of four presentations that look at motor unit firing behaviour during manipulations of muscle length, force and velocity, as well as with induced pain and superimposed vibration. The symposium will commence with a study looking at motor unit recruitment thresholds and firing rates in the human gastrocnemius muscle where changes in muscle fascicle length were manipulated. Single motor units recorded with indwelling electrodes as well as muscle fascicle length changes, measured using ultrasound, during different ramp rates of isometric contractions revealed that the shortening velocity of fascicles significantly influences the recruitment threshold of motor units. The second presentation, also investigating a lower limb muscle, tibialis anterior, looked at comparing its motor unit firing properties, utilising a surface EMG array, during low and high force isometric contractions at slow and fast ramp rates. An additional variable, muscle pain, was also considered by utilising a controlled pain or no-pain condition. The results revealed that changes to motor unit firing behaviour with induced pain are force and velocity dependent. While the observed changes allow force output to be maintained during the pain condition, the changes may have consequences in terms of increased muscle fatigue. While the first two presentations utilised isometric contractions, the third presentation investigated motor unit firing patterns in tibialis anterior using high-density surface EMG during dynamic contractions at different velocities, which is often considered to be a challenge due to movement artefacts, electrode shift, non-stationarity etc. The results showed that using this technique, motor units can be extracted during eccentric and concentric contractions at different speeds and as such, the technique can be used to investigate neural drive during dynamic tasks. The fourth and final presentation looks at the effect of vibration on motor unit behaviour to ascertain whether muscle spindle activity might explain the difference in firing rate between slow and fast isometric contractions. Single motor units were decomposed from a surface 5-pin sensor overlying biceps brachii. A difference in firing rates between contraction speeds, with and without vibration, indicted that muscle spindle activity may have an influence on firing rates during ramp contractions at different rates. Each of the four studies reveal novel findings that further our understanding of human motor unit behaviour and will also present a variety of advanced methods used to collect motor unit properties. Each of the presenters will take questions in relation to their study as well as questions that relate to the overall theme of the symposium.
S3. Eccentric vs Concentric Contractions: Basics and Applications
Presenters: Ken Nosaka, Edith Cowan University; Janet Taylor, Edith Cowan University; Yasuo Kawakami, Waseda University; Kazunori Nosaka, Edith Cowan University
Distinct characteristics exist between lengthening and shortening of activated muscles. This symposium will discuss how eccentric and concentric contractions are different in the central and peripheral levels, and how muscles respond differently to them.
S4. Neuromuscular control of body mechanics: novel insights from innovative experimental methods
Presenters: Eric Perreault, Northwestern University; Matthew Tresch, Northwestern University; Jonathan Shemmell, University of Otago; Yasin Dhaher, Northwestern University
Moving purposely throughout our world requires an ability to regulate the mechanics of our bodies. Regulation of internal mechanics is essential for distributing loads within the body while physical interactions require us to regulate the mechanical interface we present to the environment. While the net result of these actions is easily appreciated, the neural and biomechanical mechanisms contributing to them are often poorly understood due the challenges associated with measuring the actions of muscles, tendons, and neural pathways in functionally relevant conditions. The purpose of this symposium is to review recent studies that have expanded our knowledge of the neural and biomechanical factors contributing to the regulation of joint and body mechanics. In all cases, this insight arises from the use of novel measurement techniques and experimental paradigms that permit a level of inquiry previously difficult to attain.
S5. International Motoneuron Society: from motoneuron activity to motor control
Presenters: Francesco Negro, Universita’ degli Studi di Brescia; Charles J Heckman, Northwestern University Feinberg School of Medicine; Christopher K Thompson, Temple University; Utku Yavuz, University of Twente; Allison Hyngstrom, Marquette University
This symposium will show recent improvements in the analysis of motor unit discharge patterns for the decoding and interpretation of the synaptic organization of motor commands. All invited speakers will be members of the International Motoneuron Society.
S6. Tools to examine neuromuscular adaptation to muscle fatigue during movement execution
Presenters: Laurent Bouyer, Université Laval; Jayne Garland, Western University; Jean-Sebastien Roy, Université Laval; Mathieu Bielmann, Université Laval
As muscle fatigue develops, the neuromuscular system compensates for the loss of force before signs of fatigue become apparent. This symposium presents how early indicators of muscle fatigue can be detected during movement for future use in injury prevention.
S7. Beyond the Development of Novel Technologies for Physical Rehabilitation Based on Neuroscience
Presenters: Fuminari Kaneko, Keio University School of Medicine; Monica Perez, Shirley Ryan AbilityLab
Barring a few studies, there are not enough established treatments to improve upper limb motor function in patients with severe impairments due to chronic stroke. Dr. Fuminari Kaneko will present cutting-edge clinical research that uses a novel augmented reality rehabilitation system for the recovery of upper-limb function in patients with stroke and other neurological impairments. The system provides visual stimulation to patients that evoke a kinesthetic illusion. He will present their perspective on how novel technologies will advance the practice of physical therapy. Dr Monica Perez will present their noninvasive electrophysiological techniques for motor recovery after spinal cord injury (SCI). They have novel data indicating cortical connections projecting to corticospinal neurons may represent a potential alternative target for enhancing motor recovery after SCI.
S8. Novel evidence for the assessment of neuromuscular adaptations from surface electromyography
Presenters: Taian Vieira, Politecnico di Torino; Kohei Watanabe, Chukyo University; Alessio Gallina, University of Birmingham; Hélio V Cabral, Universidade Federal do Rio de Janeiro; Yu-ichi Noto, Kyoto Prefectural University of Medicine
This topic will focus on innovative results showing how pain, muscle damage and ageing may affect EMG descriptors. Limitations in assessing EMG descriptors will be presented. The audience will be invited to address relevant questions in real time.
S9. How to promote EMG in clinical and sports settings
Presenters: Catherine Disselhorst-Klug, Aachen University; Bente Rona Jensen, University of Southern Denmark; Paul Hodges, The University of Queensland;
Along with the increased requirement of evidence-based treatment of musculoskeletal disorders, new technology should be accepted as an important collaborator. In clinical practice a recent implemented technology is the use of ultrasound in diagnostics, pedagogic visualization of static and dynamic body structures, and even as effect measures. However, use of surface EMG (sEMG) has not yet come to that stage as recognized and applied tool in clinical/sports practice, although possibilities for sEMG are many (within treatment and prevention of musculoskeletal complaints).