Table 2.

Study characteristics and outcomes

	Study: name of authors, year	Setting/country	Injury/injury prevention and exercise	Study design	Population	Type of feedback	Outcome measures
1	Benjaminse et al, 201529	Controlled laboratory setting/The Netherlands	ACL injury prevention. Sidestep cutting.	RCT	n=90 healthy recreational basketball players Female: 45 Male: 45 Mean age: Female: 22.3 Male: 24.9	EFA by a visual stimuli compared with IFA by a verbal stimulus Control: no feedback. General instructions prior to task. VAF: “Bend your trunk forward, bend your knee and keep your knee straight above your foot”. (p2) Enough time to warm up and familiarisation. Three trials	Vertical ground reaction force, knee kinetics and knee kinematics (sagittal angles and moments of the trunk, hip, knee, ankle and range of motion. Frontal knee plane moment) for acquisition and retention. Two retention sessions without feedback: after 1 week and 4 weeks.
2	Gokeler et al, 201528	Outpatient physical therapy facility/The Netherlands	MSK injury: postop ACL reconstruction. (>4 months post-ACLR). Single leg hop jump.	Between-group experimental design (randomisation)	n=16 patients Female: 7 Male: 9 Mean age: Internal focus: 23.75 External focus: 22.63	EFA versus IFA. VAF: EFA: “… I want you to think about pushing yourself off as hard as possible from the floor”. IFA: “… I want you to think about extending your knees as rapidly as possible”. (p116) 5 min warm-up. Three times practice. Five trials. 30 s recovery time trial/jump.	Jump distance, knee valgus angle at initial contact, peak knee valgus angle, knee flexion angle at initial contact, peak knee flexion ankle, total ROM and time to peak angles for acquisition. (Successful jump if patient could keep balance for at least 2 s postlanding).
3	Laufer et al, 200723	Military outpatient physical therapy/Israel	MSK injury: <4 months postgrade 1 or 2 ankle sprain. Balance training on a dynamic stabiliometer.	RCT	n=40 volunteers. Female: 4 Male: 36 Mean age: IFA: 21.1 EFA: 20.5	EFA versus IFA. VAF: EFA: “Keep your balance by stabilising the platform”. IFA: “Keep your balance by stabilising your body”. (p106) Two practice trials (30 s each) Two tests (20 s each) 30 s rest between trials	Main outcome measure: overall stability for acquisition and retention (48 hours). APSI, OSI and MLSI.
4	Prapavessis and McNair, 199924	University of Auckland/New Zealand	MSK injury risk: prevention of injury of lower limb. Vertical jump.	RCT	n=91 volunteers Female: 35 Male: 56 Augmented: 41 (26 males and 15 females) Sensory: 50 (30 males and 20 females) Mean age: 16.07	VAF versus IF VAF: (focus on the control of specific joint movement during landing); “When you do your next jump, position yourself on the balls of your feet with bent knees just prior to landing. On landing, lower the heels slowly to the ground and bend the knees until well after the landing”.24 (p354) IF: use the experience of their first jump to land in a way that would minimise the stress of their next landing. No warm-up, break and practice reported.	Reduced GRF from vertical jump for short-term effect for acquisition.
5	Rotem-Lehrer and Laufer, 200725	Military outpatient physical therapy department/Israel	MSK injury: <4 months postgrade 1 or 2 ankle sprain. Balance training on stabiliometer.	RCT	n=36 male volunteers Mean age: 20.9	EFA versus IFA. EFA: “Keep your balance by stabilising the platform”. IFA: “Keep your balance by stabilising your body”. (p566) 20 practice trials (20 s each). 30 s rest between trials.	Acquisition and transfer of a learnt balance capability/postural control to a more advanced task (48 hours). APSI, OSI and MLSI
6	Weilbrenner, 201426	Oregon State University/ USA	MSK injury risk: prevention of ACL injury. Double leg jump task.	Thesis project: blocked randomisation design (counterbalance). Unpublished.	n=31 volunteers with no injury Female: 16 Male: 15 Feedback: 8 females and 7 males Mean age: 21.3 Control: 8 females and 8 males Mean age: 21.0	EFA versus control group. Both groups were told to ‘jump as high as possible’. Feedback group received additional instruction: VAF: (One-time dose of external feedback) “Focus on landing as light as a feather”. (p20) Warm-up, three practice trials, 30 s rest between the five training trials.	Change of landing biomechanics for prevention of ACL injury (acquisition and retention, 48 hours). Successful trial if participants landed with both feet at the same time and in the right position.

ACLR, anterior cruciate ligament reconstruction; APSI, Anterior/Posterior Stability Index; EFA, external focus of attention; GRF, ground reaction force; IF, intrinsic feedback; IFA, internal focus of attention; MSK, musculoskeletal; MLSI, Medial/Lateral Stability Index; OSI, Overall Stability Index; postop ACL, postoperative anterior cruciate ligament; RCT, randomised controlled trial; ROM, range of motion; VAF, verbal augmented feedback.