Sex differences in delayed onset muscle soreness induced by fatigue and measured by different methods

Abstract

BACKGROUND: Controversial outcomes from different methods for assessment of delayed onset muscle soreness (DOMS) in male and female may influence clinical decisions. AIM: In this study, we determine sex differences in pain perception and pain thresholds in a DOMS condition resultant of a fatigue protocol. METHOD: 11 male and 15 female healthy adults were submitted to an exercise fatigue protocol to induce DOMS in the quadriceps muscles. Pain perception was determined using a numeric pain rate scale (NRS) and pressure pain thresholds (PPT) were determined by mechanical pressure in the vastus lateralis (VL) and rectus femoris (RF) regions. Data were compared between methods and sexes at baseline, immediately after (0h), and 48 h after DOMS induction. RESULTS: Results showed normalized lower PPT and higher NRS outcomes after fatigue, without sex differences. Absolute values of PPT showed lower values in females comparing both time and sex (VL and RF, baseline p =0.002 and p =0.009; 0h p= 0.002 and p = 0.001; 48h p<0.001 and p<0.001) with a mean difference for females and males on 0h and 48h of from baseline VL 16,52% and 19.7%; -15.64% and -10.89%; RF 12.18% and 20.7%; -9.18% and -1.97%. No correlations were found between the number of repetitions of exercise nor the rate of perceived effort and DOMS outcomes. CONCLUSION: Men and women show similar DOMS when NRS and normalized PPT outcomes are considered. Absolute PPT values may lead to a confusing analysis of fatigue exercise-induced DOMS if merging both sexes in the sample.