week 3 Flashcards
What is a complex system?
A sysem composed of numerous interconnected elements, or degrees of freedom, that interact with each other, often in a non-linear and unpredictable manner, to achieve a common goal
Example of complex system
Soccer team–>
Parts/degrees of freedom: players, coach, physio
interconnection: rules, communication, tactics
Purpose: score goals, win, make money
Characteristics of complex systems
- Many independant and variable components (dfs)
- complex system can self organise
- Behaviour is non-linear
- Different levels (effect of exercise: physio, neuro, muscular etc)
- Capacity for stable and unstable relationships between system parts: when walking parts spontenously adjust
Microscopic components
many joints, body segments
Mesoscopic components
Mesoscopic: multiple organ systems (nervous, circulatory, skeletal, etc)
Macroscopic components
Macroscopic: when movin, body parts spontaneously adapt and adjust to each other (self-organisation)
Interdependancy
Cardiovascular endurance limits skill performance (interaction of subsyetms)
Non linerality is what?
Linear increase in cardiovascular endurance does not result in linear improvements in skill performance
Micro and Macro (circulatory system example)
Micro (inside an artery): RBC’s seem to flow in a direction but tumble about
Macro (whole circulatory system): Arterial flow moves away from the heart, venous flow towards
Constraints with complex systems is what?
Factors that limit or enable specific behaviours
E.g schools of fish, in presence of a shark it influences the fishes behaviour
In complex systems, state of order emerge/self organise under the influence of constraints
Physical constraints
Functional: vision, hearing, strength, aerobic fitness, etc
Structural: limb length, muscle csa, body fat, strength of childs grip, etc
Informational constraint
Forms of energy flowing through a system when moving in the environment (optical, auditory, haptic)
E.g Haptic (touch) information recieved when you pick up objects of differing sizes
Humans as complex adaptive systems example
Human body walking
degrees of freedom: bones, muscle, nerves
Coordinative structures: Femur, hip flexor muscles, femoral nerve
Constraints: when challanges or changes arise, such as walking up hill, these components must adjust and re-organise so we can continue to achieve task goal
Self organisation/adaptive behaviour: shorten stride, length, trunk lean, increase force from quad
Complex adaptive system example soccer
Degree of freedom: players
Coordinative structure: team formation, tactics
constraints: offence vs defence
self organ/AB: stretch and asynchrony vs compact and synchrony
How does coordination happen in a complex system?
While walking you might cooridnate your arm swings (in phase vs anti phase)
Stable states of coordination= attractor states (functional, efficient)
e.g when speed walking it feels uncomfy so youll slow down to walk or speef up to run)
All different states of organisation that can b hypotheticially formed are known as the …?
numerical phase space (includes every movement and position on field)
Self organization in sport
Allows us to adapt our behaviour to changing environmental conditions
E.g: playing surfaces in tennis (effects run, stop, turn)
The broader attractor landscap the more adaptive the system/player
Transitions between attractor states :phase transitions
- The walk to run transition (you dont immedately run, their are phases you go through to reach the running stage)
HKB model (use the finger thing as an example)
- modifying a control parameter (in this case velocity) can reduce stability of a coordinated pattern
- The attractor landscape is shifted
- the system moves from less stable pattern (anti-phase) to stable (in phase)
Self organisation (skiing example)
- Their bodys position will self organise to produce a perfect turn
- ## This coordinated behaviour self organises under the environmental and individual constraints (snow, visual info)
Task constraints
equipment
rules/markings
goals
Interaction of constraints (orgasnismic, task, environmental)
The interaction of constraints on the neuromuscular system of the performer results in the emergence of different states of co-ordination that may become optimised with practice and experience
Bernstein’s Degrees of Freedom
Degees of freedom of a body= number of joints
7 DOF for arm: 3 shoulder, 1 elbor, 3 in wrist
Degree of freedom: what happens with early learners?
- They will reduce DOF by freezing
- Joints will become stiff and frozen
DOF with practice?
Unfreezing
previously frozen linkages become fixed
muscle synergies will develope ( task specific cuplings between limbs and muscles that help manage the complexity of movement) helps system cope with moevement
efficient fluid movement
DOF difference between novice and pro in football
Nov: often straight leg, later bends but torso is still straight
Pro: Learnt to adapt co-ordinative structures for kicking a ball (more fluent) + adapted to other conditions (wider attractor state)
Movement degeneracy?
Is the capacibility of a compelx system to reach a goal in a variety of ways (e.g touching your nose)
Role of variability
Allows for adaptibility to variability from opponents
Makes it harder for opponents to pre-determine your move
Funnel shaped model for the role of variability
Athletes are shown a wide range of variability in the beginning of their training, serving as a specific function in performance in the end
3 types of Newells model of constraints
Organismic, Environmental, task constraint
