A Proposed Test To Determine Physical Working Capacity At Pain Intensity Threshold (PWCPIT)

PURPOSE: This study aimed to establish a method for assessing physical working capacity at the fatigue threshold using perception of the leg muscle pain intensity threshold (PIT) on a scale of 0-10, termed PWCPIT. We examined how PWCPIT compares with recognized fatigue thresholds: Physical working capacity at the heart rate threshold (PWCHRT), and physical working capacity at the oxygen consumption threshold (PWCVO2). The study had two primary objectives: first, to evaluate whether the mathematical model previously used to estimate PWCHRT and PWCVO2 could be adapted for PIT to estimate PWCPIT, and second, to compare the power outputs associated with PWCPIT against those derived from PWCHRT and PWCVO2. METHODS: Fifteen male volunteers (age 21.8 ± 2.3 years, height 176.53 ± 6.22 cm, weight 76.41 ± 8.83 kg, VO2peak 37.35 ± 7.71 mL/kg/min-1) underwent an incremental exhaustion test and four 8 minute randomly ordered work bouts on different days at 70-100% VO2peak (85 to 320 W) to establish their PWCPIT, PWCHRT and PWCVO2. A one-way repeated measures ANOVA with Bonferroni post hoc tests and a zero-order correlation matrix were used to analyze these thresholds RESULTS: No significant differences were found in evaluated thresholds and power output between PWCPIT (123.57 ± 38.64 W), PWCHRT (119.62 ± 47.45 W), and PWCVO2 (144.89 ± 52.17 W). Significant correlations were observed between PWCPIT and PWCHRT (r = 0.684, p = 0.005), and PWCPIT and PWCVO2 (r = 0.6, p = 0.018), but not between PWCHRT and PWCVO2. CONCLUSIONS: The results of this study indicated that the mathematical model used to estimate PWCHRT and PWCVO2 can be applied to ratings of perceived leg muscle pain intensity during cycle ergometry to determine PWCPIT. By identifying PWCPIT, trainers or therapists may tailor cycle ergometry exercise programs to avoid exceeding the pain intensity threshold, ensuring a balance between effectiveness and comfort for the individual.