Table 1.

Reviewed studies based on chronic ankle instability and if it predisposes individuals to non-contact knee injuries.

Study	PEDro Score	Subjects	N	Age (years)	Tasks	Measures	Comparison	Outcome
M. Terada, (2014)	5	19 subjects with CAI. 19 subjects in the control.	38	CAI: 20.11 ± (1.6) Control: 21.32 ±(4.0)	Vertical stop jump	Peak ATSF, posterior GRF, lower extremity kinematics (knee, ankle, hip)	CAI was compared to the control group	CAI did not show significant greater peak anterior tibial shear force (ATSF). No difference in posterior ground force reaction (GFR) at ATSF. Presence of CAI reduces availability of degrees of freedom. Difference between groups at ATSF in dorsiflexion approached significance. Patients with CAI had less knee flexion at ATSF. No group differences in hip flexion.
P. A. Gribble, (2009)	5	19 subjects with CAI. 19 subjects in the control.in young volleyball players	38	CAI: 20.3 ± (2.9) Control: 23.1 ± (3.9)	Double leg take off while landing on a single leg	TTS in AP and ML directions, Measurements were taken for plantar flexion, knee and hip flexion.	CAI was compared to the control group	TTS was longer on anteriorposterior in CAI (reduced dynamic stability). Decreased sagittal knee flexion at ground impact in CAI. No main differences were seen in ankle plantar flexion or hip flexion.
C. Doherty, (2015)	5	28 subjects with CAI. 42 subjects who were ankle copers	70	CAI: 23.2 ± (4.9) Copers: 22.7 ± (1.7)	Drop landing task onto one leg	Kinematics and kinetics of ankle, knee and hip. Ground reaction forces (GRF)	CAI group was compared to ankle copers	CAI group had position of increased hip flexion during pre-initial contact, reduced flexor movement following initial contact, and an increase in hip joint stiffness after initial contact. No differences between angular displacement of the knee and ankle in CAI and copers group.
R. D. Ridder, (2015)	5	28 subjects with CAI 28 subjects were the control	56	CAI: 22.3 ± (2.7) Control: 22.5 ± (1.6)	Barefoot forward and side jumps	Ground reaction forces (GRF), Ankle Knee and Hip ROM.	CAI group is compared to control group	Analysis of kinematics curves of the hip, knee and ankle displayed no differences between the CAI and control group.
C. Brown, (2011)	5	21 mechanical ankle instability 23 functional ankle instability 20 copers 24 control	88	MAI: M 18.6 ± (3.3) F 19.9 ± (1.0) FAI: M 20.5 ± (1.7) F 20.1 ± (1.5) Copers: M 19.8 ± (1.2) F 20.3 ± (1.1) Control: M 19.8 ± (1.3) F 20.2 ± (1. 0)	Single leg landings from a 50% maximum vertical jump	Lower extremity kinematics, trunk movement and ground reaction forces (GRF)	Comparisons were made between the four groups	No differences seen between groups for ankle plantar flexion and dorsiflexion, inversion/eversion, internal-external rotation. Knee rotation the FAI group and copers were less variable than controls. Copers were less variable for knee flexion than controls. For hip flexion MAI, FAI, and copers were less variable than controls. MAI was less variable than controls for hip abduction. The FAI group was less variable than control in hip flexion during the lateral jump. The MAI and FAI were less variable than controls in hip abduction during the anterior jump. For the trunk the MAI and control were less variable than FAI in trunk lateral flexion.
E. Delahunt, (2006)	5	24 subjects with Functional Instability 24 subjects were the control		FI: 25 ± (1.3) Control: 22 ± (0.84)	Single leg jump onto a force plate	Compare electromyography (EMG) of rectus femoris, peroneus longus, tibialis anterior, and soleus. Compare angular displacement and angular velocities of the lower leg. Also compare kinetic patterns.	Functional instability group and a control group	The functional instability group indicated a decrease in pre-IC peroneus longus IEMG. There were no differences shown in the other three muscles. FI subjects were less efficient than the control in reaching the closed packed position of the ankle joint. Subjects had a decreased dorsiflexion position. FI subjects had a less externally rotated hip during pre-IC.