Table 1.

Qualitative Content Analysis: Description, Definition, and Effect of Identified Principles and Their Key Descriptors.

Name	Definition	Effect	Key Descriptors
Massed practice	The number of repetitions performed	Small effects on improvement and retention17,19,22,24	- Number of repetitions was counted - Tasks were aimed at increasing number of repetitions of a movement
Dosage	Training of more than 5 hours a week	Can speed up functional recovery17,19,20,22	- Training is more than 60 minutes of therapy per session and week day
Structured practice	Training schedule with frequent and longer breaks	Better retention than massed protocols17,19,52	- Rests were given during during the session
Task-specific practice	Movements performed are relevant for ADL and goal oriented	Learning is maximal if the task trained is specific17,19	- Tasks incorporated movements that are functionally meaningful (reaching, lifting, grasping pronation, supination, pinching, etc) and were goal oriented - Tasks or movements were relevant for ADL
Variable practice	Several tasks that require different movements	Better retention and enhances generalization16	- Training included various tasks that require a variety of movements
Multisensory stimulation	Providing feedback through multiple senses	Restoration of sensorimotor contingencies19	- Besides visual, other types of feedback were provided (auditory, tactile, etc)
Increasing difficulty	Progressively increase the difficulty of the task or the involved movements	Augment task-specific use of the impaired limb22	- Difficulty or complexity of tasks or movement is changing depending on ability, performance, or time
Explicit feedback	Knowledge about results (task success or failure, or movement outcome)	Retain an adapted movement better18	- Providing cues on task completion with regard to success or failure, or movement outcome (trajectory errors, average completion time, or exactness) - Feedback can also be provided through a therapist
Implicit feedback	Knowledge about performance that is obtained from tracking, analyzing, and visualizing kinematic movement data	Reduce the sensorimotor prediction error and promote learning18	- Real-time visualization of arm/hand movement and other kinematic properties (speed, rotations, synergies compensations) - Display of correct trajectory to follow
Avatar representation	Active execution and observation of movement through an avatar	Degree of agency aids learning from sensorimotor prediction error21	- Virtual movement is represented as a human- or body part–like avatar (whole body, arm, or hand)
Promote use of affected limb	Tasks that are forcing or reinforcing the use of the affected arm	Counteracting learned nonuse17,19,22	- Tasks were designed or required to be performed with the paretic limb - Tasks cannot be accomplished by the healthy arm only

Abbreviation: ADL, activities of daily living.