Efficacy of Aerobic Exercise Versus Therapeutic Exercises on Exercise-induced Hypoalgesia in Knee Osteoarthritis

exercise induced hypoalgesia (EIH) of the medial compartment of the knees, measured by the change in pressure pain threshold (Δ PPT)

Within session change in pressure pain threshold at the rectus femoris muscle, calculated as post exercise minus pre exercise values and averaged bilaterally, measured with a digital algometer and expressed in kilograms force per square centimeter.

Within session change in pressure pain threshold at the upper trapezius muscle descending portion, calculated as post exercise minus pre exercise values and averaged bilaterally, measured with a digital algometer and expressed in kilograms force per square centimeter.

Change in pressure pain threshold at the medial compartment of the knee, rectus femoris and upper trapezius between baseline and post intervention, averaged bilaterally and expressed in kilograms force per square centimeter.

Change in the conditioned pain modulation effect assessed by a standardized conditioned pain modulation test, defined as the change in pressure pain threshold at the volar forearm during and after an ischemic conditioning stimulus on the contralateral arm, with pain intensity standardized around four out of ten on a numeric rating scale.

Average knee pain intensity over the past seven days at rest and after movement, measured on an eleven-point numeric rating scale from zero (no pain) to ten (worst imaginable pain). Numeric Rating Scale for Pain Intensity. Range 0 to 10, with 0 indicating no pain and 10 the worst pain imaginable. Higher scores indicate greater pain intensity.

Pain Self Efficacy Questionnaire. Ten items scored 0 to 6 each, total score 0 to 60. Higher scores indicate better outcome, greater pain related self efficacy.

Knee Injury and Osteoarthritis Outcome Score. Subscales are transformed to a 0 to 100 score, where 0 represents the worst knee health status and 100 the best. Higher scores indicate better outcome, better knee related health status.

Patient Specific Functional Scale. Each selected activity is rated from 0 to 10, where 0 means unable to perform the activity and 10 means able to perform as before the problem. The total score is the mean of the three activities, range 0 to 10. Higher scores indicate better outcome, better patient specific functional status.

Number of full sit to stand repetitions completed from a standard height chair in thirty seconds, higher counts reflecting better lower limb strength, dynamic balance and functional performance.

Maximal voluntary isometric contraction of the quadriceps measured with a handheld dynamometer in a standardized seated position, normalized to body mass and expressed as a percentage, with higher values indicating greater strength.

Global Perceived Effect scale. Eleven point scale ranging from minus 5, much worse, to 0, no change, to plus 5, completely recovered. Higher scores indicate better outcome, greater perceived recovery.

Proportion of attended exercise sessions relative to the thirty planned sessions, calculated as attendance percentage sessions attended divided by sessions planned multiplied by one hundred.

Perceived enjoyment during physical activity or exercise, assessed using the Brazilian Portuguese version of the Physical Activity Enjoyment Scale (PACES). The PACES includes 18 items answered on a 7 point bipolar scale, in which participants indicate how they felt about the exercise session just completed. Scores will be calculated according to the item recoding instructions of the instrument, with higher scores indicating greater perceived enjoyment of physical activity.