Table 5.

Results

	Study	Effect	Motor control stages and authors’ conclusion	Additional comments/overall risk of bias within the study
1	Benjaminse et al, 201529	Females in VER group had greater knee flexion angles compared with females in CTRL and VIS group in each of the sessions (p<0.05). The males in VIS group had significantly larger vGRF in all sessions compared with males in the VER and CTRL group (p<0.05) The males in the VIS group had greater knee flexion moments compared with males in the VER and CTRL groups (p<0.05) regardless of sessions. Males in the VIS group reduced knee valgus moment over time. Males in VER and CTRL group did not. Females in the VER group reduced their knee varus moment (non-significant change) over time.	Acquisition & retention Male participants benefit from visual feedback. Visual feedback reduces knee joint loading in males with high retention	No testing of transfer Unclear risk of bias
2	Gokeler et al, 201528	Mean jump distance, knee valgus angle at IC, peak knee valgus angle, time to peak knee valgus ankle and valgus ROM: no significant difference between IFA and EFA (p>0.05). Knee flexion at IC: no significant group difference for non-injured legs (p=0.82). For injured legs it was a significantly smaller knee flexion in IFA group (p=0.04). Peak knee flexion: significantly lower in IFA group for non-injured legs (p=0.01) and for injured legs: (p=0.01) compared with EFA. IFA time to peak knee flexion for non-injured leg was significantly shorter (p=0.01) and for injured leg (p=0.0.02) compared with EFA.	Acquisition EFA is more beneficial than IFA for motor skill performance	No control group. Only short-term effect (no follow-up). Low statistical credibility: small sample size (n=16). No testing of transfer. Unclear risk of bias.
3	Laufer et al, 200723	Stability level 6: Main effect of time for APSI (p<0.001). No such effect for OSI and MLSI. Significant interaction between group and time for OSI (p=0.030) and APSI (p=0.019). Between post-training and pretraining: only EFA group had a significant decrease in OSI (p=0.030) and in APSI (p<0.001). Stability indices: no significant difference between post-training and retention. Stability level 4: it looks as if something is wrong with the lay out of this in the PDF-file. Can you change that please? Main effect of time for OSI (p=0.010) and for APSI (p<0.001) (significant improvement). No such effect for MLSI Acquisition phase: Improvements for OSI (p=0.011) and APSI (p<0.001). Retention phase: no significant difference Stability indices: no effect APSI EFA group: trend toward significant interaction between time and group (p=0.078).	Acquisition & retention VAF (EFA) is advantageous for learning postural control task (especially for acquisition phase) over three sessions	No control group. Low statistical credibility: small sample size (n=40) Gender difference: males>females. No testing of transfer. Unclear risk of bias.
4	Prapavessis and McNair, 199924	No significant difference between Trial 1 (prior to feedback) GRF of the sensory and AF group. A significant difference was present between Trial 2 (postfeedback). AF group: lower GRF compared with sensory feedback group. AF group: a significantly lower GRF was also observed in Trial 2 compared with Trial 1.	Acquisition Adolescents need more information than that provided by their prior experiences in jumping—to lower GRF in landing. It is evident that those receiving VAF can pick up instructions related to improvements of lower limb kinematics	No control group. Only short-term effect (no follow-up). Gender: males>females. No testing of transfer. Unclear risk of bias.
5	Rotem-Lehrer and Laufer, 200725	Statistically significant group-by-time interaction OSI: (p=0.001), APSI: (p=0.03) and MLSI: (p=0.01). Significant difference of pretraining and post-training for EFA in all stability measures: (p<0.05). Change over time for IFA was not significant.	Acquisition and transfer. VAF (EFA) is advantageous for transfer of postural control task over a 3-day period	No control group. Low statistical credibility: small sample size (n=36). Gender: only male participants. Good: testing transfer. Unclear risk of bias
6	Weilbrenner, 201426	Kinematics: Knee flexion angle at initial contact: significant main effect (p=0.026), but no significant time (p=0.433) or group-by-time interaction effects (p=0.523). Feedback group had significantly greater knee flexion compared with control. Frontal plane knee angle at initial contact: no significant main effects for time (p=0.469) or group (p=0.752) and no significant group-by-time interaction effect (p=0.288). Peak knee valgus angle: no significant main effects for time (p=0.223) and group (p=0.844) or group-by-time interaction effects (p=0.775). Kinetics: Peak knee extension moment: no significant main effect for time (p=0.588) and group (p=0.747) or group-by-time interaction (p=0.908). Peak anterior tibial shear force: significant main effect for time (p=0.017), but no significant effect for group (p=0.329) or group-by-time interaction (p=0.029). Subjects across groups: significantly greater PATSF at retention than baseline. Peak knee varus moment: no significant main for effects for time (p=0.792) or group (p=0.752), and no significant group-by-time (p=0.801) interaction effect.	Acquisition & retention The VAF did not change landing biomechanics	Low statistical credibility: small sample size (n=31). No testing of transfer. Unclear risk of bias.

AF, augmented feedback; APSI, Anterior/Posterior Stability Index; CTRL, control; EFA, external focus of attention; GRF, ground reaction force; IC, initial contact; IFA, internal focus of attention; MLSI, Medial/Lateral Stability Index; OSI, Overall Stability Index; p, p-value; PATSF, peak anterior tibial shear force; VAF, verbal augmented feedback; VER, verbal; vGRF, vertical ground reactions force; VIS, visual.