Genes,
Training, and other Constraints on Individual Performance: A Role for
Dynamical Systems Theory? Keith Davids Department
of Exercise and Sport Science, Manchester Metropolitan University, Alsager, Cheshire ST7 2HL, UK. Email: k.davids@mmu.ac.uk Sportscience
5(2), sportsci.org/jour/0102/kd.htm, 2001 (1460 words) Reviewed by Greg Anson, Physical Education,
University of Otago, Dunedin, NZ Behavioral
genetics and psychology provide useful insights into relative contributions
of nature and nurture to variation in physical performance in a population,
but understanding and exploiting these and other constraints on performance
in individual athletes requires an over-arching multi-disciplinary
theoretical framework. Dynamical systems theory, which has enjoyed some
recent success in accounting for behavior of complex systems, may be the
appropriate framework. Reprint pdf · Reprint doc KEYWORDS:
athlete, environment, nature, nurture, skill |
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Informative articles in the current and previous issues of
Sportscience address the relative importance of innate (genetic) and
environmental (training) effects on athletic performance (Hopkins, 2001;
Baker, 2001). Hopkins presented the limited
evidence that differences in genes and training contribute to differences in
sport talent before presenting practical implications of this view that
“athletes are born and made”. Baker
evaluated the argument that “sport performance and
sport expertise are entirely the result of hours spent in focused, effortful
training rather than innate, inheritable traits” and concluded that “future
research should also consider an approach to sport expertise that
investigates the inter-dependent role of genetic and environmental factors”. Both authors alluded to the resolution of the
nature-nurture debate via the identification of the proportion of performance
variation accounted for by inherited characteristics and environmental
influences in populations or groups of athletes. In this commentary, I argue
for a new perspective on this continuing debate, one that involves
understanding the interacting contributions of genes, training, and other
effects on an individual athlete. A
theoretical framework for capturing and making practical use of the interaction
of so many interacting factors in the individual will need to be complex and
multidisciplinary. I believe dynamical systems theory is such a
framework. Dynamical
systems theory provides explanations for some of the phenomena that arise in
complex natural systems, such as the weather and social organizations.
Dynamical systems in nature are composed of many interacting parts or degrees
of freedom, and are constantly pressurised by
constraints to change the state of organization between component parts. This
description fits human movement, which is composed of many interacting
sub-systems (nervous, musculo-skeletal, endocrine,
and so on). Accounts of the application of dynamical systems theory to the
acquisition of expert movement behavior can be found in Davids
et al. (2001), Davids et al. (2002), and Newell
(1986). See also Rosenbaum (1998) for the skeptical view that the theory is,
as yet, more descriptive than explanatory. A key
question from a dynamical systems viewpoint concerns how coordination emerges
from the interaction between the degrees of freedom during goal-directed
movements, such as catching a ball or performing a triple salto.
In the study of the acquisition of sport expertise in humans, dynamical
systems theory can explain how movement coordination and control change over
time scales required for learning and development (weeks, months, and years). What
influences change in dynamical movement systems? To answer this question, a
model of the emergence of expertise under interacting constraints is useful. The concept of constraints has a rich
tradition in theoretical physics and evolutionary and theoretical biology.
Roughly speaking, constraints are factors that shape or guide the
organization of multi-component natural systems including, for example,
weather systems, termite colonies, and movement systems. Newell (1986) has
provided the best account of how constraints influence coordination and
control in human movement systems. His model categorizes constraints as
“organismic” (exemplified in the current debate by the genetic profile and
amount of task-specific practice of each individual athlete), “task” (related
to the specific characteristics of each sport or physical activity; examples
include rules, boundaries, and equipment), and “environmental” (exemplified
by social and cultural influences on behavior). Newell’s model shows how
these constraints interact together to influence expertise in sport. A radical implication of this approach is
that the acquisition of expertise emerges under the interaction of
organismic, task, and environmental constraints. It is
important for sport scientists to understand the full range of key
constraints on each individual sport performer during the acquisition of
expertise in a specific sport or physical activity. Hopkins and Baker are
correct in pointing out that major constraints on expertise are genes and
training, but it is clear from dynamical systems theory that the constraints
on the acquisition of expertise in sport for each individual are many and
interacting. Focusing on the
interaction of constraints has several implications for the acquisition of
expertise in individual athletes. First, as
Hopkins and Baker suggest, we are only just beginning to understand the
genetic and training basis for success in some sports. Although inherited
traits are significant constraints on the upper limit of performance
attainable by each individual, there is no guarantee of success for an
individual athlete without extensive and intensive specific practice. Athlete
A with a higher genetic disposition for speed endurance, but little desire to
train, will not achieve the same level of performance as athlete B, with a
solid endurance capacity, but who trains much harder, and has access to
quality coaching and facilities. Practice might not necessarily make perfect,
but quality time spent in training could give genetically under-endowed
learners a better chance of success. Second,
even if genetic screening of individual learners is accepted as ethical,
other constraints will limit or enhance the possibility of success at the
highest levels. For example, a genetic predisposition for endurance needs to
be specifically complemented by psychological characteristics such as mental
toughness, tactical astuteness and motivation to endure pain during training
and competition. Third,
environmental constraints such as lack of social and familial support could
either spur an individual on to greater heights or nip promising careers in
the bud. Individuals can react in many different ways to such constraints.
Access to good coaching, sport science support, training equipment and
facilities are also needed to allow genetic constraints to be expressed. From a
practical perspective, coaches and sport scientists need to understand that
there are potential “gradients of success” for each athlete. These gradients,
or limits to performance potential, are constrained by many factors,
including genetic predisposition, quality of training experiences, exposure to high quality coaching, availability of
comprehensive sport science services, cultural, familial and social
expectations and support, and access to equipment and facilities. How the
full range of constraints interacts to limit or enhance the performance of
each individual athlete can be considered in the form of a performance
profile or athlete history. Although developing a checklist of constraints
might help our understanding of the acquisition of expertise in a particular
sport, the whole is greater than the sum of the parts. Performance at the
highest levels of sport cannot be determined in a mechanistic or formulaic
manner, since compensatory behavior in some athletes (for example, more
rigorous approach to training or acquisition of sponsorship funds to access
highest quality of coaching) can mediate effects of key constraints, such as
genetic make up. Since expertise emerges under the interaction of key
constraints, all of which differ for each individual athlete, compensatory
variability in the path to success should be seen as the norm. For example,
despite the growing evidence of genetic predisposition for speed endurance,
not every Kenyan international long-distance runner ends up as an Olympic
medal winner or world champion. While it
is important to know that 25% of variability in athletic performance between
individuals may be determined by genes, or that 10 years of task-specific
practice needs to be undertaken by most experts, we need to know more about
the way genes, training, and other constraints combine to produce expert
performances in the individual. Group-based analysis is limited for
individual performance behavior, whereas a constraints-led perspective from
dynamical systems theory provides a way forward. References Baker J (2001). Genes and training
for athletic performance revisited. Sportscience 5(2), sportsci.org/jour/0102/jb.htm
(2032 words) Davids
K, Williams AM, Button C, Court M (2001). An integrative modeling approach to
the study of intentional movement behavior. In Singer RN, Hausenblas
H, Jannelle C (editors): Handbook of Sport
Psychology (2nd edition) (pages 144-173). New York, NY: John Wiley Davids
K, Bennett SJ, Button C (2002). Coordination and control of movement in
sport: an ecological approach. Champaign, IL: Human Kinetics Hopkins,
WG (2001). Genes and training for
athletic performance. Sportscience
5(1), sportsci.org/jour/0101/wghgene.htm
(1899 words) Newell KM
(1986). Constraints on the development of coordination. In Wade M, Whiting
HTA (editors): Motor Development in Children: Aspects of Coordination and
Control (pages 341-360). Dordrecht, Germany: Martinus
Nijhoff. Rosenbaum
DA (1998). Is dynamical systems modeling just curve fitting, Motor Control 2,
101-104 Edited and webmastered by Will Hopkins. |