Table 2 Overview of extracted MITS^a elements

1

Position

Describes the position of the individual during MI practice as task-specific or not task-specific.

Physical

Task-specific

2

Location

Describes the location of MITS as task-specific or not task-specific.

Environment

Task-specific

3

Focus

Each task consists of different parts. Focus of the intervention classifies the main focus of task-related activities that had to be imagined: motor, cognitive or strength.

Task

Motor-focused activities

4

Order

Describes temporal order of MI and PP^c trials. MI trials could have been performed before, between, after or simultaneously with PP.

Timing

MI after PP

5

Integration

Describes whether MI practice has been added to PP or embedded ^dinto PP.

Added

6

MI instructions medium

MI instructions can be provided differently through one or more media types. Media type was scored as acoustic, written or visual. More than one media type could be assigned.

Learning

Acoustic

7

Instruction mode

In addition to the instruction medium, the mode was classified as live or pre-recorded (for example, using tape or video).

Live

8

Supervision

MITS could have been supervised or not supervised by an instructor present during the session.

Supervised

9

Directedness

MITS could have been directed ^dor non-directed when stepwise guidance was present or not.

Non-directed

10

Instruction type

The description of MI instructions varied. Instructions could cover detailed descriptions for each part of the task that had to be imagined, simple keywords, or coarse (broad) overall MI instructions.

Detailed

11

Instruction individuali-sation

MI instructions could have been individualised to the participant's problems with the task that had to be imagined (tailored), or could have been the same for each participant (standardised).

Standardised

12

Familiari-sation

Describe whether study participants had received an MI familiarisation session before the MI intervention began.

No familiarisation

13

Change

Indicated whether modification of content, duration or dosage of the MI training occurred, to facilitate the learning process during the MI intervention period.

14

MI session

MITS could have been classified as group sessions with more than one person participating in a MITS or as individual sessions with one participant only.

Emotion

Individual

15

Eyes

During the MI, the participant's eyes could have been closed or open. In some interventions, participants started with one condition and changed to the other after one or several MITS.

Closed

16

Perspective

During the MI, participants could have imagined the task from an internal or external perspective. In some interventions, participants started with one condition and changed to the other after one or several MITS.

Perspective

Internal

17

Mode

During the MI, participants could have used a kinaesthetic or visual mode. In some MI interventions, participants started with one condition and changed to the other during one or after several MITS.

Kinaesthetic