L4 Reach and Grasp Flashcards
Critical Events
key biomechanical components to successfully complete the task
Stage 1 of development of functional hand skills
Learning Approach–lots of feedback
Sensory Focus–exploration
Arm/Wrist Movements–limited
Hand/Grasp actions–power grip
Stage 2 of development of functional hand skills
Learning Approach: skills match ability
Sensory Focus: feedback acquisition
Arm/Wrist Movements: Previous experience
Hand & Grasp: Transferring hand to hand
Stage 3 of development of functional hand skills
Learning Approach: discovery of optimal approach
Sensory Focus: maturing of motor organization
Arm/Wrist Movements: Organization and efficiency
Hand & Grasp Actions: raking, lateral pincer, tip to tip pincer
Precision Grasp
development focused on radial side, forces directed between thumb and fingers
Lateral pincer, tip pincer, palmar, tripod variations
Lateral pincer
thumb pad to medial side of index finger
Tip pincer
tip of thumb to index in opposition
Palmar
thumb opposition to both index and middle finger
Tripod Variations
palmar with object to thenar space
Power grasp
development focused on ulnar sider, finger and thumb pads directed towards palms, transmit force to object
hook, spherical, cylindrical
Prehension
incorporates both precision and power
In-hand manipulation
one hand holds and manipulates with various patterns
palm to finger, finger to palm, shift, simple rotation, complex rotation
In-hand Stabilization
object within palm does not move
Handedness
(left handed or right handed) affected by genetics, the environment, intrauterine and birth-related stresses and trauma
Distance Programming
visual perception of distance, activation of agonists, then activation of antagonist to slow
ability to plan and execute movements that involve covering a specific distance. It involves determining the appropriate force, timing, and trajectory needed to move the body or an object over a certain distance
Throwing a ball a certain distance, kicking a soccer ball to a specific point on the field, or jumping over an obstacle
Location programming
relative tensions exist between agonists and antagonists. locations in space correspond to these tension relationships
involves planning and executing movements to reach or interact with a specific spatial location or point. It focuses on targeting a precise location in space, often requiring fine motor control and accuracy in the movement trajectory
Reaching for an object on a table, touching a specific point on a touchscreen device, or placing a cup on a coaster.
Activation with Reach
Eye–> Head –> Hand
emphasis on role inertia for successful coordination
Grasp
anticipatory control in precision grip
shaping of hand occurs during transportation of reach
role of perception plays big role in grasp
Grasp and Lift Tasks
Discrete phases to any lifting task
- Contact between fingers and object to be lifted
- Grip and load force increase
- Load force increases enough to overcome weight of object and movement occurs
- Decrease in grip and load forces after contact surface
Feedforward
Anticipatory Control
Visual and somatosensory control of reach grasp involve characteristics of object, vision, proprioception
Feedback
reactive response, error correction for unanticipated perturbations to the movement
visual in reach/grasp = final accuracy
somatosensory in reach = muscle spindles
somatosensory in grasp = cutaneous afferents
Steps of locating a target
- Locate object in space
- Stabilize gaze
- Shifting gaze
- Tracking movements
Regulatory Environment
aspects of the environment that shape the movement itself
shape of object, weight of a cup, surface
Non-regulatory environment
aspects of the environment that may contribute to the performance, but the movement itself does not conform to the aspects
background noise, distractions
