WOMAC subscale measurements consisted of knee pain, which encompassed questions 1 through 5. Joint stiffness involved questions 6 and 7, and physical functioning was covered by questions 8 through 24. The WOMAC instrument is an established, reliable, and validated, disease-specific, self-administered questionnaire. It assesses the perceived measurement of three subscales: pain, stiffness, and physical functioning of knee and hip OA(17). Each question is scored on a 5-point Likert scale: none-0, mild-1, moderate-2, severe-3, and extreme-4. Higher scores on the WOMAC indicate greater perceived pain, stiffness, and functional limitations.
The effect of the self-massage intervention on knee ROM, both flexion and extension, was measured using a universal goniometer with 14-inch arms. This instrument’s measurements have been tested for validity and reliability(18).
The first null hypothesis of the study was as follows: The intervention of self-massage would have no effect on the pain, stiffness, and physical functions of participants with knee OA as demonstrated in their responses to the WOMAC questionnaire.
The second null hypothesis of the study was that the self-massage intervention would have no effect on knee ROM in terms of flexion or extension as assessed using a goniometer.
The analyses of covariance (ANCOVA) were used to test differences between control and experimental groups using Statistical Package for the Social Sciences (SPSS) 20(19). This package was used to code and tabulate collected data and test the two hypotheses of WOMAC and knee ROM. Analyses of covariance (ANCOVA) were used to test differences between control and experimental groups after controlling for preexisting factors. The independent variable was grouped, with two levels—control and experimental. Twenty-eight analyses were conducted, 24 for aspects related to WOMAC measures, and four related to knee ROM measures. Postscores for each of the 28 measures were included as dependent variables in the analyses, with prescores as covariates.