Convergent evidence for construct validity of a 7-point likert scale of lower limb muscle soreness.

OBJECTIVES: The aim of this study was to examine the construct validity of the 7-point Likert scale of muscle soreness, assessing its relationship with Visual Analogue Scale (VAS). An additional aim was to examine its sensitivity as measure of symptom of eccentric-contraction muscle damage. DESIGN: Correlational study. SETTING: Self-administered questionnaires collected in field setting. PARTICIPANTS: Twenty-six soccer players. INTERVENTIONS: 4-week preseason training camp, which included high-intensity plyometric training sessions. MAIN OUTCOME MEASUREMENTS: Players self-reported the perceived muscle soreness of the lower limbs using the VAS (criterion measure) and the 7-point Likert scale of muscle soreness. RESULTS: Significant individual correlations were found between the 2 muscle soreness scales (mean r=0.80+/-0.07; range, 0.65 to 0.94). The correlation using the pooled data was 0.81. No significant muscle soreness scale x time interaction was found for standardized measures of muscle soreness (P=0.98). The main factor for time (24, 48, 72, and 96 hours after the first plyometric training session) was significant (P=0.0001). Effect sizes for the changes in the Likert and VAS absolute scores during the first 96 hours were similar (partial eta=0.13). CONCLUSIONS: The results of this study provide further convergent evidence for the construct validity of the 7-point Likert scale of muscle soreness. The 2 scales showed similar sensitivity to muscle soreness caused by eccentric contractions during the first 96 hours after plyometric exercises.