Effects of Maximal Eccentric Trunk Extensor Exercise on Lumbar Extramuscular Connective Tissue: A Matched-Pairs Ultrasound Study

Recently, it has been shown that the extramuscular connective tissue (ECT) is likely involved in delayed onset muscle soreness (DOMS). Therefore, aim of present study was to investigate effects maximal trunk extension eccentric exercise (EE) on ECT thickness, self-reported DOMS, stiffness, skin temperature, and possible correlations between these outcomes. Healthy adults (n = 16, 29.34 ± 9.87 years) performed fatiguing EE trunk. A group highly active individuals (TR, n 8, > 14 h sport per week) compared with a less (UTR, < 2 week). Ultrasound measurements stiffness MyotonPro IndentoPro, temperature infrared thermography, pain palpation (100 mm visual analog scale, VAS) as surrogate for DOMS were recorded before (t0), immediately (t1), 24 (t24), 48 (t48) after EE. thickness increased from t0 t24 (5.96 7.10 mm, p 0.007) t48 7.21 0.001). VAS also (15.6 23.8 0.001) 22.8 Skin t1 (31.6° Celsius 32.7° Celsius, 0.032) 32.9° 0.003), while remained unchanged (p 0.05). Correlation analysis revealed no linear relationship outcomes within 48-hour measurement period. The results may confirm previous findings involvement genesis extremities paraspinal extensors. Subsequent work should focus interventions targeting prevent or reduce strenuous