Motor Control Models & Loops
What does “open-loop control” mean?
Movement is pre-planned and runs without feedback once initiated.
What is the main idea behind Schema Theory in motor control?
We store generalized rules or relationships between movement parameters and outcomes, allowing us to adapt skills to new situations.
Movement emerges from the interaction of what three elements?
Individual, Task, and Environment
Define kinematics vs kinetics.
Kinematics = description of motion; Kinetics = forces that cause motion.
What does QMD stand for?
Qualitative Movement Diagnosis
Define motor development.
Change in motor behavior over the lifespan influenced by biological and environmental factors.
What does “closed-loop control” rely on most?
Sensory feedback to make corrections during movement.
Name one invariant characteristic and one parameter of a GMP.
Invariant = relative timing / force / sequence Parameter = overall duration / muscles used
Give an example of a task constraint in sport.
Scoring rules, required equipment (e.g., must dribble in basketball)
In a 2nd-class lever, where is the load located?
Between the fulcrum and effort
In which stage is feedback given to the performer?
Intervention stage
List the 4 stages of motor development.
Reflexive → Voluntary → Proficient/Smooth → Refined/Automatic movement
Which part of a gymnast’s tumbling pass is open-loop vs closed-loop?
Take-off = open-loop; landing adjustments = closed-loop.
Why does practicing under many different conditions help learning?
It strengthens the schema rules that generate future movements.
Distinguish a regulatory vs non-regulatory environmental constraint.
Regulatory directly affects movement (surface, lighting); non-regulatory should not (crowd noise).
During a lateral raise, the arm moves from 45° to 90° relative to the body. What happens to torque demand and why?
Torque increases because moment arm increases
Give one factor to consider during the preparation stage.
Knowing the performer, rules of the activity, and deciding what to observe.
At what level of arousal is peak motor performance achieved?
Moderate arousal, growth and learning zone, window of tolerance
In motor control, what is “feed-forward”?
A predictive command sent before movement begins (planning, not reacting)
How can movement variability benefit performance?
It offers flexibility to accomplish a task in multiple ways and adapt to perturbations.
What happens when a control parameter changes enough to destabilize a system?
The system self-organizes into a new attractor state or movement stops.
State Newton’s First Law of Motion.
An object stays at rest or in uniform motion unless acted on by a net external force.
List at 5 types/examples of interventions
Two athletes are the same age, but one has greater strength, coordination, and recovery ability. What explains this difference?
Biological age
An athlete performs a rapid throw with no time for feedback, but improves timing across attempts based on past errors. Give a theory informed explanation.
Open-loop during movement; schema updated between trials
A tennis player practices only cross-court forehands and looks very consistent in practice. In a match, their performance drops when they must hit down-the-line or adjust to different speeds.
What explains the drop in performance?
Lack of variability limits adaptability
Now argue why athlete A may perform better.
Better immediate performance due to consistency and low variability
A sprinter pushes backward and downward into the track to move forward. Which Newton’s law and force vector direction best explain this?
Newton’s 3rd Law: for every action there’s an equal and opposite reaction; force vector directed backward and downward creates forward motion.
A volleyball player consistently hits serves too far left. What type of error is this and what is the best correction strategy?
Constant error
An athlete trains hard because they personally value improvement, not because of rewards or pressure. What type of motivation is this?
Self-determined extrinsic motivation
A sprinter explodes out of the blocks. A coach tells them to “push forward”. What change in performance of the block start do you expect and why?
None because no time to implement feedback.
Explain a situation that would require more variable practice vs less variable practice for the same skill.
Two athletes practice a skill:
Athlete A repeats the exact same movement every time. Athlete B practices with varied speeds, distances, and contexts
Later, both are placed in a new game situation they have never seen before.
Which athlete will perform better and why?
Athlete B; variability builds adaptable schema for new situations
A physical therapist modifies an exercise by decreasing external load but increasing the distance of the load from the joint. The patient will most like report that the:
exercise feels just as difficult.
Explain what an AT may do when preparing to cover for a different sport.
What is system develops first in children?
Sensory