Keynote Lectures

Combating Muscle Loss and Weakness in Old Age
Marco Narici, University of Nottingham, United Kingdom, United Kingdom

Influence of Genetic Factors on Responses to Exercise Training and Sport
James S. Skinner, Independent Researcher, United States, United States

Recent Technological Advances in Golf
Robert J. Neal, Independent Researcher, United States, United States

Analysis of Muscle Coordination in Sports: Perspectives from Electromyography and Elastography
François Hug, The University of Queensland, Australia, Australia

Abstract

Several factors are known to contribute to sarcopenia (Fig.1) but amongst these, neuroendocrine changes are commonly regarded as primary drivers of this process. These are responsible for degeneration of a-motoneurons and of the neuromuscular junction (NMJ) and for muscle fibre denervation, also fuelled by mitochondrial dysfunction and oxidative damage at the NMJ, leading to a loss of motor units and muscle weakness. In fact, one of the crucial systems severely affected in aging is the loss of effective connection between muscle and nerve, leading to a pathological non-communication between the two tissues. There is now growing evidence that cross-talk between muscle and nerve via anterograde/retrograde axonal transport influences motoneuron survival, NMJ integrity, motor unit number and muscle fibre phenotypic, metabolic and functional characteristics. Several neurotrophic and myotrophic factors have indeed been found to orchestrate these changes and many of these, such as brain-derived neurotrophic factor (BDNF) and insulin like growth factor (IGF-1) have potent neuroprotective and myotrophic effects and are modulated by physical activity and nutrition.

It is well established that sarcopenia can be markedly mitigated through strength training (provided a sufficient training volume is used to overcome the anabolic resistance to training typical of old age) but what seems novel and particularly exciting is the observation that the practice of regular physical activity, such as running, seems to protect from neuromuscular degeneration. Recent neurophysiological studies indeed report no decline in motor units in the lower limb muscles of master runners (MA) compared to old sedentary individuals.^,  Indeed, muscle peak power (PP) of MA is, at any given age, greater than that of sedentary CTRL, to the extent that at the age of 70 years PP of MA is comparable to that of CTRL in their 40’s. Furthermore, the regular physical activity of MA seems to preserve muscle architecture from age-related changes associated with sarcopenia, as values of fibre length and pennation angle of the knee extensors are not different from those of young CTRL.

It is not clear how physical activity affords protection against motor unit loss but this could be due to a reduction of inflammation in response to regular physical activity and also by preservation of the neurotrophic and myotrophic  actions on motoneurons and on the NMJ.

(Supported by EU FP7 grant 223576, project Myoage)

Abstract

Health and fitness can be affected by many genetic and non-genetic factors. Genetic factors influence how people are at the present time and how they respond to external stimuli or changes in environment (example, exercise training). There are high, average, and low responders to training, as well as adverse and non-responders. The speed of change and the extent to which changes occur are affected by genetic factors. This lecture gives a basic introduction to the field of genetics and how it applies to training and to sport.

Abstract

Golf is a sport that has fanatical participants, observers and coaches. Equipment manufacturers have, over the last 15 years in particular, sought to extract every possible advantage for the players by improving the equipment that is available (e.g., club head designs, golf ball aeronautics and golf shaft characteristics). They are virtually at the point now where very few (if any) major developments are possible in the design and manufacture of the player’s equipment. On the other side of the equation, coaches and players have sought technologies that allow them to understand and monitor the way the club and ball interact as well as how the body segments move and interact to do work on the golf club. There have been three major technological improvements that have occurred in this field of endeavor over the last 10 years including real time 3D analysis and biofeedback, systems to measure the movement of the club head during impact and the motion of the golf ball, and systems designed to provide analysis and real-time feedback at the interaction of the player and the ground. This presentation will focus on the first two of these three technologies, providing both data and background information on the technologies used to measure these phenomena. It is the integration of such technologies that will allow coaches to better understand how players deliver the club to the ball and how interventions (e.g., biofeedback training), can be used to bring about movement pattern change.

Abstract

Due to muscle redundancy, one basic problem in many scientific fields (e.g., biomechanics, neurophysiology and engineering) is to understand how muscles are coordinated to adequately perform common motor tasks. An understanding of muscle coordination is also important for rational planning of therapeutic intervention in clinical populations. It is also important for athletes so that the influence of various factors, such as the use of specific equipment or training intervention, can be better quantified. To date, muscle coordination is mainly described using surface electromyography (EMG).

This lecture will focus initially on the main intrinsic drawbacks of the EMG technique and processing. This will be followed by discussion of “muscle synergy analysis”. This technique is used to decompose EMG patterns recorded from numerous muscles into the summed activation of just a few muscle synergies. As such muscle synergy analysis can offer insight into underlying neural control strategies of movement. Finally, I will present pilot experiments showing that elastography (supersonic shear imaging) can be used to accurately quantify change in force in an individual muscle during an isometric contraction. This experimental technique offers promising perspectives to quantify sharing load during various tasks.