Table 1.

Summary of included studies

Study	Study design, level of evidence (CEBM)	Participants, n, mean age, sex	Injury	Intervention	Outcome	Effect size (Cohen’s d)	Relative size
Cryotherapy
Hopkins et al 13	RCT, 1b	n=30 (30 AKE), age=22, 11F/19M	AKE	3 groups (cryotherapy, TENS and control). Cryotherapy group had 2 plastic bags containing 1.5 L of partially crushed ice placed directly on the knee for 30 min. A typical TENS protocol was used. The treatment session lasted 30 min.	H-reflex (at 45 min).	3.21	Huge.
Rice et al 14	RCT, 1b	n=15 (15 AKE), age=35, 5F/10M	AKE	2 groups: cryotherapy and control. The cryotherapy group had ice around their knee joint for a 20 min period. The control group did not receive the cryotherapy intervention and remained seated for 20 min before performing postintervention measurements.	MFCV. MVIC.	1.62 1.21	Huge. Very large.
Hart et al 15	RCT, 1b	n=30 (ACLR), age=27, 20F/10M	AMI (CAR<90%) post-ACLR	3 groups: 1. 20 min of knee joint cryotherapy. 2. An hour of therapeutic rehabilitation exercises. 3. Cryotherapy followed by exercises. The patients attended 4 supervised visits over a 2-week period.	MVIC: 1. Cryotherapy + exercise. 2. Cryotherapy alone. 3. Exercise alone.	1.4 0.58 0.3	Very large. Medium. Small.
Kuenze et al 16	Case series, 4	n=20 (10 ACLR, 10 healthy), age=22, 9F/1M	Post-ACLR	The intervention included cryotherapy application to the knee joint followed by lower extremity muscle stretching, progressive strengthening exercises and balance training.	MVIC. CAR.	0.34 1.22	Small. Very large.
GRADE=moderate
Exercise
Lowe and Dong26	Case–control, 3b	n=18 (9 ACLR, 9 healthy), age=20, 11M/7F	AMI post-ACLR	Hamstring fatigue was induced by instructing participants to perform squats until rating of perceived exertion was 15 out of 20 (or ‘hard’) and their heart rate was approximately 150 beats/min.	CAR.	1.27	Very large.
Kuenze et al 16	Case series, 4	n=20 (10 ACLR, 10 healthy), age=22, 9F/1M	Post-ACLR	The intervention included cryotherapy application to the knee joint followed by lower extremity muscle stretching, progressive strengthening exercises and balance training.	MVIC. CAR.	0.34 1.22	Small. Very large.
Hart et al 15	RCT, 1b	n=30 (ACLR), age=27, 20F/10M	AMI (CAR<90%) post-ACLR	3 groups: 1. 20 min of knee joint cryotherapy. 2. An hour of therapeutic rehabilitation exercises. 3. Cryotherapy followed by exercises.	MVIC: 1. Cryotherapy + exercise. 2. Cryotherapy alone. 3. Exercise alone.	1.4 0.58 0.3	Very large. Medium. Small.
Lepley et al 17	Prospective cohort, 2b	n=46 (36 ACLR/10 healthy), age=22, 16F/33M	Post-ACLR	4 treatment groups: 1. NMES and eccentric exercise. 2. Eccentrics-only. 3. NMES-only. 4. Standard of care. NMES and eccentrics received a combined NMES and eccentric protocol postreconstruction.	MVIC: 1. NMES + eccentric. 2. Eccentrics-only. 3. NMES-only.	1.05 1.25 0.03	Large. Very large. Negligible.
GRADE=moderate
NMES
Lepley et al 18	Prospective cohort, 2b	n=46 (36 ACLR/10 healthy), age=22, 16F/33M	Post-ACLR	Healthy controls and 4 treatment groups: 1. NMES + eccentric exercise. 2. Eccentrics-only. 3. NMES-only. 4. Standard of care. NMES and eccentrics received a combined NMES and eccentric protocol postreconstruction.	LSI: 1. NMES + eccentric. 2. Eccentrics-only. 3. NMES-only.	0.43 0.3 0.16	Medium. Small. Small.
Lepley et al 17	Prospective cohort, 2b	n=46 (36 ACLR/10 healthy), age=22, 16F/33M	Post-ACLR	4 treatment groups: 1. NMES and eccentric exercise. 2. Eccentrics-only. 3. NMES-only. 4. Standard of care. NMES and eccentrics received a combined NMES and eccentric protocol postreconstruction.	MVIC: 1. NMES + eccentric. 2. Eccentrics-only. 3. NMES-only.	1.05 1.25 0.03	Large. Very large Negligible.
Glaviano et al 27	RCT, 2b	n=18(18 knee pain, CAR<90), age=24, 8F/10M	AMI (CAR<90%) + knee pain	The treatment intervention was a 15 min patterned electrical neuromuscular stimulation, applied to the quadriceps and hamstring muscles.	MVIC.	No effect.
GRADE=low
TENS
Son et al 19	RCT, 1b	n=30 (30 AKE), age=23, 5F/10M	AKE	TENS or placebo treatment was administered to each group for 20 min, following infusion of hypertonic saline.	MVIC.	1.34	Very large.
Konishi et al 20	RCT cross-over, 2b	n=12 (12 healthy), age=22, 12M	Vibration-induced quads activation failure	A cross-over design that involved 2 sessions for each participant was used. For up to 30 s before and then during the MVC, the participants were randomly assigned to receive TENS applied to the skin covering the knee joint or no TENS.	MVIC.	0.76	Large.
Hopkins et al 13	RCT, 1b	n=30 (30 AKE), age=22, 11F/19M	AKE	3 groups (cryotherapy, TENS and control). Cryotherapy group had 2 plastic bags containing 1.5 L of partially crushed ice placed directly on the knee for 30 min. A typical TENS protocol was used. The treatment session lasted 30 min.	H-reflex (at 45 min).	1.23	Very large.
Hart et al 21	RCT, 2b	n=30 (30 ACL), age=32, 10F/20M	ACL injury	All patients attended 4 sessions of supervised quadriceps strengthening exercises over 2 weeks prior to surgery. Patients were randomly allocated to 3 groups: 1. Exercises alone. 2. Exercise while wearing a sensory TENS device on the knee joint. 3. 20 min of knee joint cryotherapy immediately prior to each daily exercise session.	MVIC: 1. Exercise only. 2. Exercise + TENS. 3. Exercise + cryotherapy.	No effect over exercise.
GRADE=low
Vibration
Pamukoff et al 22	RCT, 1b	n=20 (20 ACLR), age=21, 14F/6M	Post-ACLR	3 groups: LMV, WBV or control (sham). A custom-made LMV stimulator was affixed to the quadriceps tendon. During the WBV condition, subjects stood in an identical position as in the LMV intervention on a vibrating platform that provided the same stimulus (2 g of acceleration at a frequency of 30 Hz).	AMT: WBV. LMV. CAR: WBV. LMV. MVIC: WBV. LMV.	1.82 1.42 0.82 0.80 0.56 0.44	Huge. Very large. Large. Large. Medium. Medium.
Blackburn et al 23	RCT, 1b	n=45 (45 AKE), age=21, 28F/17M	AKE	3 groups: WBV, LMV and control. After intra-articular injection of 60 mL of saline, the WBV and LMV groups were then exposed to vibratory stimuli previously demonstrated to facilitate quadriceps function, and the control group performed these same procedures without vibratory stimuli.	The CAR and MVIC improved in the WBV and LMV groups (p<0.05) immediately postintervention, but not in the control group.	NA (no SD provided).
GRADE=very low
Ultrasound
Norte et al 24	RCT, 1b	n=30 (30 knee injury), age=23, 15M/15F	Knee injury with AMI (CAR<90), (22/30 ACL)	2 groups: ultrasound and control (sham). An ultrasound or sham treatment was applied to the anteromedial knee. The transducer was manually moved at an estimated rate of 4 cm/s over an area delineated by a custom template twice the size of the transducer surface area for a duration of 17 min.	H-reflex (20 min postintervention).	0.58	Medium.
GRADE=very low
TMS
Gibbons et al 28	RCT, 1b	n=20 (20 partial meniscectomy), age=38, 6F/14M	Partial meniscectomy with AMI (CAR<85)	2 groups: TMS and control. Participants in the experimental group received TMS over the motor cortex that was contralateral to the involved leg and performed 3 maximal quadriceps contractions with the involved leg.	No significant difference in CAR or MVIC was seen between groups (p=NS).	No evidence for TMS over control.
No evidence for efficacy
Taping/Brace
Kim et al 29	RCT, 2b	n=16 (16 knee injury), age=24, 7F/9M	Knee injury with AMI (CAR<90)	2 groups: Kinesio taping and sham. H-reflex of the vastus medialis and quadriceps. CAR and MVIC were measured before taping and 20 min after tape was applied over the rectus femoris. All outcomes were measured again after tape was removed when participants returned to the laboratory 24–48 hours after taping.	No significant difference between groups in H-reflex, CAR or MVIC (p=NS).	No evidence for use of Kinesio taping.
Oliveira et al 30	RCT, 1b	n=47 (47 ACLR), age=29, 47M	Post-ACLR	2 groups: control, placebo and Kinesio taping. Kinesio taping group participants were submitted to Kinesio taping on the femoral quadriceps of the affected limb, while placebo group subjects used the same procedure without the tension proposed by the method. The control group remained at rest for 10 min.	None of the variables analysed showed significant intergroup or intragroup differences (p=NS).	No evidence for use of Kinesio taping.
Davis et al 31	Cross-over, 4	n=14 (14 ACLR), age=23, 9F/5M	Post-ACLR	3 groups: brace, sleeve or nothing. Participants performed a standardised aerobic exercise protocol on a treadmill.	No differences were seen between bracing conditions after aerobic exercise (p=NS).	No evidence for use of bracing.
No evidence for efficacy
Other
Drover et al 32	Case series, 4	n=9 (9 AKP), age=26, 5F/4M	AKP	The treatment intervention included the treatment protocols described in the ART lower extremity manual for the patella tendon, vastus medialis, vastus intermedius, vastus lateralis and rectus femoris.	Knee extensor strength (MVIT) and knee extensor inhibition were not significantly different.	No evidence for use of ART.
Ageberg et al 33	RCT, 2b	n=39 (39 ACL), age=24, 29F/20M	Post-ACLR	2 groups: local cutaneous application of anaesthetic (EMLA) or placebo cream. 50 g of EMLA, or placebo, was applied on the leg 10 cm above and 10 cm below the centre of patella, leaving the area around the knee without cream.	No statistically significant differences were in the EMLA group or in the placebo group.	No evidence for use of temporary cutaneous anaesthesia.
Warner et al 34	RCT, 2b	n=12 (12 knee injury), age=26, 4F/8M	Knee injury with AMI (CAR<90)	3 groups: Superficial heat using a moist heat pack (77 °C). Sham using a moist pack (room temperature). Control (no treatment).	No significant difference in either CAR or MVIT (p=NS).	No evidence for use of superficial heat.
No evidence for efficacy

ACLR, ACL reconstruction; AKE, artificial knee effusion; AKP, anterior knee pain; AMI, arthrogenic muscle inhibition; AMT, active motor threshold; ART, active release technique; CAR, central activation ratio; F, female; LMV, local muscle vibration; M, male; MFCV, muscle fibre conduction velocity; MVC and MVIT, MVIC EMLA (Eutectic Mixture of Local Anesthetics); MVIC, maximal voluntary isometric contraction; NA, not available; NMES, neuromuscular electrical stimulation; RCT, randomised controlled trial; TENS, transcutaneous electrical nerve stimulation; TMS, transcranial magnetic stimulation; WBV, whole body vibration.