Table 2 Characteristics of included studies

Abraham et al. (2017) [63]

Sample of 25 active female dance students with a minimum of three years dance experience

Intervention group (n = 13) aged 13.51 ± 0.49 and control group (n = 12) aged 13.63 ± 0.52

Two elevé tasks, a repeat (10 repetitions of 3 s) and static (hold 10 s at maximum height) task were imagined for 20 to 25 min per session. 2 sessions per week for 6 weeks delivered as a group session in the dance studio

Upper body exercises (postural awareness, mobility, and strength) while seated, 2 times per week for 6 weeks

1) Maximal ankle plantarflexion angle

2) plantarflexion ROM

3) symmetry index

Post-intervention

No significant differences between groups during pre-measurements. MI improved repeat task in maximal plantarflexion angle (p = .04) and ROM (p = .02) for the intervention group during post-measurements. No statistically significant results on ankle plantarflexion maximal angle or ROM were noted in the static task

Bouguetoch et al. (2021) [64]

Sample of 37 (aged 24 ± 5.8 years) healthy participants, 12 females, were recruited. Motor imagery group (n = 10, 4 females), control group (n = 7, 2 females), NMES + MI group (n = 10, 3 females), and NMES group (n = 10, 3 females)

10 MI training sessions (5 per week) under supervision in the laboratory. 40 maximal isometric plantar flexion movements of the right leg were imagined over 6 s, with 6 s rest. Participants were seated on the isokinetic ergometer during the training sessions

The control group did not perform any exercise

Additional intervention groups:

The NMES group underwent 40 evoked contractions of the triceps surae muscles and the NMES + MI group underwent 20 imagined and 20 evoked contractions

1) isometric torque

2) EMG activity

3) Muscle architecture

Post-intervention

A significant improvement was demonstrated for the NMES and MI group, as compared to the control group (p < 0.001 and p = 0.0023) and NMES + MI group (p = 0.004 and p = 0.002)

There was no significant difference between the NMES and MI group (p = 0.934)

Christakou et al. (2007) [32]

20 participants with a grade II ankle sprain in sports (± 5.0 ± 2.4 days after trauma) aged 25.4 ± 4.76 years (range 18–30)

Participants first underwent 60 min of normal physiotherapy and continued with visualization of ankle dorsal- and plantarflexion ROM, strengthening exercises, proprioceptive training, stationary cycling, forward lunges, step-ups and -downs, diagonal hops and stretching exercises for 45 min. In total 12 sessions, 3 times per week. Motor imagery was done while seated in a quiet place

12 sessions of 60 min physiotherapy with hydromassage, laser and exercises: ankle dorsal- and plantarflexion ROM, strengthening exercises, proprioceptive training, stationary cycling, forward lunges, step-ups and -downs, diagonal hops and stretching exercises. 3 times per week

1) muscular endurance

2) functional stability

3) dynamic balance

Post-intervention

The MI group showed significantly greater muscular endurance (p = .017) compared to the control group. No other significant differences between the experimental and control group were observed using Bonferroni corrections

Christakou & Zervas (2007) [31]

18 athletes with grade II sprain (5 ± 2.49 days after trauma) aged 26 ± 4.47 years (range 18 to 30 years) and at least 2 years of athletic experience

Participants underwent relaxation and imagery for 45 min in addition to 60 min physiotherapy. A relaxation technique was used before MI, participants sat on a quiet place and imagined the exercises as conducted during the physiotherapy session as instructed by the investigator

12 sessions of 60 min physiotherapy including hydro-massage, ultrasound, laser, and exercises: ankle ROM, strengthening, proprioceptive, stationary cycling, step-ups and down, diagonal hops and stretching

1) VAS

2) swelling

3) ROM

Post-intervention

The results did not show a significant difference between the experimental and control group and between the measurements and the intervention group versus control group on pain (p = .74), edema (p = .78) and ROM (p = .78)

Dehghan et al. (2013) [62]

16 sports teams with 25 healthy football players per squad (n = 400) aged 16 to 18 years were recruited

Mental and proprioceptive exercise for 6 months

No mental and proprioceptive exercises

1) proprioception

2) Number of ankle inversion traumas

Post-intervention

Proprioceptive and MI exercises improved proprioception (p = .000) and reduced the number of injuries (p = .027) compared to the control group

Grosprêtre et al. (2017) [61]

18 healthy young adults not involved in intense sport activities were recruited. Participants in the intervention group (n = 9) were aged 22.2 ± 2.6 years and in the control group (n = 9) 23.2 ± 2.8 years

4 series of 25 imagined maximal isometric contractions of the plantar flexors of the right leg were carried out seated and strapped on an isokinetic dynamometer, daily during seven days for 20 min per session

No exercise during the study (one week)

1) isometric torque

2) rate of torque development

Post-intervention

A significant interaction effect between time and group was found on MVC torques (p = .024). Only the MI group significantly improved MVC torque. A significant interaction was found between time and group for EMG activity in the M. soleus (p = .039) and M. gastrocnemius caput medialis (p = .024)

Nagar & Noohu (2014) [60]

30 healthy, male, collegiate basketball players were recruited. The intervention group (n = 25) was aged 20.53 ± 2.2 years and participants in the control group (n = 15) were aged 20.80 ± 2.4 years

Mental imagery followed directly after the strength and balance training and took 10 min. Participant sat in a quiet place and performed breathing exercises for 2 min, followed by 3 sets of imagination of the previous performed strength and balance exercises with a 1-min rest

The intervention was carried out 3 times per week for 6 weeks

30 min of balance board exercises: double-leg stance, side to side balance with eyes open and closed and functional sports activities on 1 leg. Strength training with leg press, 4 sets building up to 6RM. 3 times per week for 6 weeks

1) balance

2) strength ankle flexors

Post-intervention

There was no significant effect of the intervention as compared to the control group for the m-SEBT in the anterior direction (p = .118), posteromedial direction (p = .169), the posterolateral direction (p = .303), and for the composite score (p = .22)

There was a significant effect for knee extensor strength (p = .023) in favour of the intervention group and no significant effect for ankle plantar flexor strength (p = .052)

Nunes et al. (2015) [30]

18 male, field soccer players, with a recent ankle sprain (< 72 h). The intervention group was aged 17.2 ± 1.6 years and the control group was aged 17.4 ± 1.8 years (range: 16—20 years)

Motor imagery after physical therapy treatment. In a quiet room participants sat in front of a computer. 40 different images of ankle–foot were projected on screen, patient had to identify a left or right ankle using the left–right arrows of the keyboard within 4 s. Time and number of right guesses was calculated at the end of the session. Intervention took place5 times per week, 2 h per session (physical therapy) plus motor imagery (< 2:40 min.)

Physical therapy treatment: cryotherapy (20 min) in first 2 sessions, electrotherapy (TENS, ultrasound, or laser) in first sessions, kinesiotherapy consisting of stretching, joint mobilization (passive and active), sensorimotor training, strengthening exercises, and return to sport exercises in the final phase. Sessions were 5 times per week and took 2 h

1) ROM

2) Postural control

3) Swelling

4) Functional instability

Post-intervention

No significant between-group differences were demonstrated for ankle dorsal flexion ROM (p = .23), plantar flexion ROM (p = .50), the m-SEBT anterior direction (p = .70), the posterolateral direction (p = .29), the posteromedial direction (p = .79), edema (p = .50), and the CAIT (p = .70)

Sidaway & Trzaska (2005) [29]

24 healthy participants were recruited and allocated to

3 groups of 8 participants: MI, EG and CG

The mean age was 22.7 years (range 19 to 26 years)

Participants in the mental and physical practice group performed 3 sets of 10 repetitions of maximal dorsiflexion contraction while seated on Biodex for 3 times per week, 4 weeks, 15 min per session

Participants did not participate in any form of practice during the 4 weeks of the experiment

1) maximal dorsiflexion torque

Post-intervention

ANOVA revealed a significant main effect for group (p =  < .01). Post-test performance on dorsiflexion peak torque was significantly higher in mental and physical practice group, not in control group (p =  < .05). There was no significant difference between the improvement for the mental practice and the physical practice group