• Quadriceps muscle isometric contraction in sitting position 1 set of 3-3 reps × 1 min hold.
• Isotonic quadriceps contraction with resistance band 3 sets of 10 reps x 1min hold.
• Isotonic hamstring contraction with resistance band 3 sets of 10 reps x 1min hold.
• Sit to stand exercise during 1 min.
• Dynamic stepping exercise (walking up and down one step/stair during 1 min).
• Standing calf stretch 3 x 20 sec.
• Standing quadriceps stretching 3 x 20 sec.
• Supine hamstring stretching 3 x 20 sec.

This is a 13-item scale for use in assessing catastrophizing in clinical and nonclinical populations. Each PCS item is rated on a 5-point scale: 0 (not at all) to 4 (all the time). People are asked to indicate the degree to which they have the above thoughts and feelings when they are experiencing pain. The PCS total score is computed by summing responses to all 13 items. PCS total scores range from 0 - 52. The PCS subscales are computed by summing the responses to the following items: Rumination: Sum of items 8, 9, 10, 11 Magnification: Sum of items 6, 7, 13 Helplessness: Sum of items 1, 2, 3, 4, 5, 12. Higher values representing greater catastrophizing.

The Tampa Scale for Kinesiophobia (TSK) is a 17 item questionnaire used to assess the subjective rating of kinesiophobia or fear of movement. Items are scored on a 4-point Likert scale with scoring possibilities ranging from 'strongly disagree' (score=1) to 'strongly agree' (score=4). This is a self-completed questionnaire and the range of scores are from 17 to 68. A total score is calculated after inversion of the individual scores of items 4, 8, 12 and 16 and then summing responses to all 17 items. Higher scores indicate an increasing degree of kinesiophobia.

The 40-meter walk test assesses the time it takes to walk short distances. Participants are asked to walk as quickly but as safely as possible to a mark 10 m away, return, and repeat for a total distance of 40 m. Subjects are timed for this test and data are expressed as speed. The time it takes to cover a specified distance is recorded in seconds and id measured with a stopwatch. This time is converted to a walking speed by dividing the distance covered by the time taken and is expressed as meters/second. Higher values represent better performance.

Maximal voluntary isometric contraction is measure with a hand-held dynamometer (Microfet 2m Hoogan Health Industries, West Jordan, UT, USA). Knee extension and flexion strength will be tested isometrically at 90° of knee flexion and hip abduction and aduction strength will be in tested in side-lying. Participants are instructed to perform 3 maximal voluntary isometric contractions for 5 seconds on each leg, with 10 seconds of rest between trials. The average muscle force of three repetitions will be calculated for each muscle group. The values are measured in kilogram-force and normalized to body weight (in kilograms).

Postural control is evaluated using two force platform (AMTI, model OR6-6-2000) and patients are asked to stand barefoot with one foot on each platform, arms along the sides, remaining as stable as possible looking to a point located 3 meters in front.

All participants will be tested under four different postural conditions (eyes open, eyes closed and firm support, foam support) during three 30-s trials with one minute of rest provided between trials . The center of pressure (COP) velocity (m/s) and amplitude for medial/lateral (m/cm2) and anterior/posterior (m/cm2) directions will be analised.

Body mass index (BMI) is a measure of body fat based on height and weight. BMI is defined as the body mass divided by the square of the body height, and is universally expressed in units of kg/m2, resulting from mass in kilograms and height in metres.