Effects of Including Interferential Current in a Therapeutic Exercise Program in Individuals With Knee Osteoarthritis

Knee Injury and Osteoarthritis Outcome Score (KOOS). It aims to evaluate the domains of pain, symptoms, activities of daily living, function related to recreation and sports, and quality of life related to the knee. Totaling 42 items, each item must be answered using a Likert scale that ranges from 0 (best score) to 4 (worst score), and the score for each subscale ranges from 0 (worst score) to 100 (best score).

The Numerical rating pain scale, a simple, easily administered scale evaluates the perceived intensity of pain, using an 11-point scale from 0, representing 'no pain', to 10, which is the 'worst possible pain'.

Knee Injury and Osteoarthritis Outcome Score (KOOS). It aims to evaluate the domains of pain, symptoms, activities of daily living, function related to recreation and sports, and quality of life related to the knee. Totaling 42 items, each item must be answered using a Likert scale that ranges from 0 (best score) to 4 (worst score), and the score for each subscale ranges from 0 (worst score) to 100 (best score).

Pain self-efficacy questionnaire, structured into 10 items where each item is evaluated by selecting a number on a 7-point numerical scale (scores from 0 to 6), where 0 means "not at all confident" and 6 means "completely confident". The items cover different functions, from work, social activities, domestic tasks and coping with pain without medication. A total score is calculated from the sum of the scores for each of the 10 items, producing a total score that ranges from 0 to 60. Higher scores reflect stronger self-efficacy beliefs.

Sit and stand test. The volunteer will sit down and stand up from a chair for 30 seconds. A researcher will time the total time it takes to complete this activity.

Patient-specific functional scale. The participant will indicate three activities that he/she has difficulty performing. For each of these activities, the participant will indicate a score from 0 to 10. Higher scores indicate how well the participant can perform the activity. Lower scores indicate an inability to perform the activity.

manual dynamometer portable (Lafayette Manual Muscle System, Modelo 01165, Lafayette Instrument Company, Lafayette, IN). Four 5-second readings will be taken during maximal voluntary isometric contraction (MVIC) with a 30-second rest period between contractions. The first CIVM will familiarize the volunteer with carrying out the task. A new set of readings will be taken if a volunteer can perform three contractions with at least 10% variability. Strong and constant verbal stimuli will be used throughout the test. Always with the research participants' hands positioned crossed on the chest. Thus, bilateral assessments of the muscles, quadriceps, and gluteus medius will be carried out. The order of CIVM readings will be randomized to avoid collection bias. The research participant will remain in lateral decubitus with a pillow positioned between the legs, with the limb to be tested superiorly in a neutral position.

The perception of the global effect of the treatment by the research participant will be evaluated by the Global Perception of Change scale. The Global Perception of Change scale is a direct scale on the patient's self-perception when the intervention is performed. This scale consists of 11 points, ranging from -5 (worsening compared to the start of treatment), 0 (neutral) and +5 (improvement compared to the start of treatment), using the Portuguese version.