The study compares two exercise strategies in people with knee osteoarthritis. The first is aerobic exercise on a recumbent cycle ergometer, with effort controlled by the Borg scale. The second is a therapeutic exercise program with resistance, neuromuscular, mobility, and balance components. The primary objective is to determine which approach produces greater exercise induced hypoalgesia, measured by the increase in pressure pain threshold at the knee within the session across four anchor sessions during a ten week program. This is a randomized clinical trial with two parallel arms. Ninety participants, between forty five and seventy five years of age, will be allocated to one of the two groups. Allocation sequence concealment will be ensured using opaque envelopes. The outcome assessor will remain blinded to group allocation. The interventions will take place three times per week for ten weeks. Assessments will be performed at baseline and after ten weeks. Within session measurements will also be taken in weeks one, four, seven, and ten. The primary outcome is the intra session change in pressure pain threshold at the medial compartment of the knee. Secondary outcomes include exercise induced hypoalgesia in the quadriceps and trapezius, chronic adaptation of pressure pain threshold, conditioned pain modulation, pain intensity, pain self efficacy, knee related health status, functional performance, quadriceps strength, global perceived effect, and adherence. The planned sample size is forty five participants per group. The analysis will follow the intention to treat principle. The primary outcome will be compared using linear mixed models with group and time effects. Clinical outcomes at T1 will be adjusted for baseline values. Estimates, confidence intervals, and interpretation in light of minimally important differences will be reported.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
90
Supervised cycling on an electromagnetic recumbent stationary bicycle three times per week for ten weeks, with at least 24 hours between sessions.
Individually supervised, land based therapeutic exercise program focusing on warm up, resisted strengthening, neuromuscular training, mobility and balance.
Cid André Fidelis de Paula Gomes
São Paulo, Brazil
Exercise-induced hypoalgesia (EIH)
exercise induced hypoalgesia (EIH) of the medial compartment of the knees, measured by the change in pressure pain threshold (Δ PPT)
Time frame: At weeks 1, 4, 7, and 10 of the 10 week intervention (within session, pre and immediately post exercise).
Exercise induced hypoalgesia of the quadriceps
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.
Time frame: Within session, immediately before and immediately after the exercise session at weeks 1, 4, 7, and 10 of the 10 week intervention.
Exercise induced hypoalgesia of the upper trapezius
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.
Time frame: Within session, immediately before and immediately after the exercise session at weeks 1, 4, 7, and 10 of the 10 week intervention.
Chronic adaptation of pressure pain threshold
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.
Time frame: Baseline and after 10 weeks of intervention.
Conditioned pain modulation
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.
Time frame: Baseline and after 10 weeks of intervention.
Pain intensity
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.
Time frame: Baseline and after 10 weeks of intervention.
Pain self efficacy
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.
Time frame: Baseline and after 10 weeks of intervention.
Knee related health status
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.
Time frame: Baseline and after 10 weeks of intervention.
Patient specific functional 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.
Time frame: Baseline and after 10 weeks of intervention.
Functional performance, thirty second sit to stand test
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.
Time frame: Baseline and after 10 weeks of intervention.
Quadriceps muscle strength
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.
Time frame: Baseline and after 10 weeks of intervention.
Global perceived effect
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.
Time frame: After 10 weeks of intervention.
Adherence to the intervention
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.
Time frame: Throughout the 10 week intervention period.
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