Table 2 Characteristics of the protocols, posture during the perturbation, conditions, outcome measures, recording methods, and the muscles analyzed

(a1) Kubicki et al., 2016 [29]

Mild cognitive impairment

14 (6/8)

Unilateral arm movement

(pointing a led)

Standing

Simple/self-paced

Predictable/unpredictable

Kinematic

(1) Maximal velocity of the index movement (m/s)

EMG

(2) Muscles onset (RF, BF, OI, and ES) with reference to activation of the DA

(3) % trials with APA (percentage for each participant)

YA

14 (9/5)

OA

14 (5/9)

(a2) Huang and Brown, 2013 [21]

YA

14

Unilateral arm movement

(pick up and grasp a cylinder)

Standing

Simple/Self-paced

Complex task

Predictable

Kinematic

(1) Movement speed (m/s)

Force platform*

(2) COP onset (s)

(3) COP amplitude (cm)

Other outcomes

(4) Jerk score

OA

16

(a3) Woollacott and Manchester, 1993 [13]

YA

16 (8/8)

Unilateral arm movement (pointing a led)

Standing

Reaction time/complex task

Predictable

Kinematic

(1) Movement speed mean (m/s)

EMG

(2) Muscle onset (HAM, ES, Q, DA)

OA

16 (8/8)

(a4) Bleuse et al., 2005 [30]

YA

10 (5/5)

Unilateral arm movement (reach and grasp a handle)

Standing

Simple/self-paced

Reaction time/complex task

Predictable

Kinematic

(1) Velocity peak (deg s)

(2) Time of peak (s)

(3) Movement duration (s)

Force platform

(4) COP onset (s)

(5) COP amplitude (mm)

(6) Time of the maximal displacement COP (s)

(7) Onset (s) vertical torque

(8) Peak vertical torque (N mm)

(9) Area prior t0 (N mm s)

(10) Area (N mm s)

(11) Duration vertical torque (s)

EMG

(12) Muscle onset (BF, Q, TA, SOL, DA)

(13) % of subjects activating a given muscle

OA

10 (8/2)

(a5) Lee et al., 2015 [18]

YA

8 (5/3)

Trunk perturbation (push a pendulum forward, using only trunk motion)

Standing

Simple task/self-paced

Predictable

Force platform

(1) COP onset (s)

(2) COP amplitude (mm)

(3) COP CPA: the COP peak values (mm)

EMG

(4) Muscle onset (TA, GAS, RF, BF, RA, ES)

(5) APA integral of baseline activity

Other outcomes

(6) C indexes describe co-activation

(7) R indexes describe reciprocal activation of agonist–antagonist muscle pairs

OA

8 (4/4)

(a6) Kanekar and Aruin, 2014 [15]

YA

13 (7/6)

Trunk perturbation (pendulum anterior impact)

Standing

Simple task/self-paced

Predictable

Force platform*

(1) COP amplitude (mm)

(2) COP CPA: the COP peak values (mm)

(3) Time of the maximal displacement COP (s)

EMG*

(4) Muscle onset (SOL, GAS, TA, RF, VM, VL, BF, ST, GL max, EO, RA, and ES)

(5) APA integral of baseline activity

Other outcomes

(6) COM at tzero

(7) COM peak

(8) Time to COM peak

OA

10 (6/4)

(a7) Claudino et al., 2013 [19]

YA

20

Trunk perturbation (pendulum lateral impact)

Standing

Simple task/self-paced

Predictable/unpredictable

Force platform

(1) COP amplitude mediolateral (mm)

(2) COP amplitude anteroposterior (mm)

EMG

(3) APA integral of baseline activity (RF, BF, GL Med, OI, RA, and ES)

OA fallers

20

OA

11 (6/5)

(a8) Inglin and Woollacott, 1988 [11]

YA

15 (8/7)

Unilateral arm movement (pull or push a manipulandum)

Standing

Simple task/self-paced

Reaction time/complex task

Predictable/unpredictable

EMG

(1) Muscle onset (GAS, TA, HAM, Q, and RA)

OA

15 (8/7)

(a9) Laessoe and Voigt, 2007 [7]

YA

14

Tilt protocol: displacement in inclination

Slide protocol: horizontal slide of the platform in the sagittal plane

Standing

Simple task/self-paced

Reaction time/complex task

Predictable

Force platform

(1) COP amplitude (mm): passive body inertia related to the platform movement

(2) COP CPA: the COP peak values (mm)

Other outcomes

(3) Frequencies of step reactions (%)

OA

10

(a10) Bugnariu and Sveistrup, 2006 [20]

YA

8 (4/4)

Slide protocol: horizontal slide of the platform in the sagittal plane

Standing

Reaction time/complex task

Predictable/unpredictable

EMG*

(1) Muscle onset (TA, GAS, Q, HAM, and ES)

Other outcomes

(4) Steps: the total number of steps (exacerbated response)

(5) COP percentage: percentage of time the COP resided in one particular region reported

OA

8 (4/4)

(a11) Aloraini 2019 [31]

YA

10 (7/3)

Pointing task

Standing

Reaction time/complex task

Predictable

Kinematic

(1) Movement time (s)

(2) Peak velocity (mm/s)

(3) Time to peak velocity (ms)

EMG

(4) Muscle onset (TA and SOL)

(5) APA amplitude

OA

10 (7/3)