Current scientific evidence suggests that when whole body vibration (WBV) is used as a warm-up prior to performing eccentric exercise, delayed-onset muscle soreness (DOMS) is mitigated and strength loss recovers faster. These benefits were observed primarily in nonresistance-trained individuals. The aim of this study was to determine if WBV could mitigate soreness and expedite strength recovery for resistance-trained individuals when used as a warm-up prior to eccentric exercise. Thirty resistance-trained males completed 300 maximal eccentric contractions of the quadriceps after warming up with (WBV) or without (CON) WBV. Both CON and WBV experienced significant isometric (27.8% and 30.5%, respectively) and dynamic (52.2% and 47.1%, respectively) strength loss immediately postexercise. Isometric strength was significantly depressed after 24 hours in the CON group (9.36% p < 0.01), but not in the WBV group (5.8% p = 0.1). Isometric strength was significantly depressed after 48 hours in the CON group (7.18% p < 0.05), but not in the WBV group (4.02% p = 0.25). Dynamic strength was significantly decreased in both the CON and WBV groups both at 24 hours (19.1% p < 0.001, and 16.1% p < 0.001, respectively), 48 hours (18.5% p < 0.01, and 14.5% p < 0.03), and 1 week postexercise (9.3% p = 0.03, and 3.5%, respectively). Pain as measured by visual analog scale (VAS) was significant in both CON and WBV groups at 24 and 48 hours postexercise, but the WBV experienced significantly less soreness than the CON group after 24 hours (28 mm vs. 46 mm p < 0.01 respectively), and 48 hours (38 mm vs. 50 mm p < 0.01). Pain as measured by pain pressure threshold (PPT) increased significantly in both groups after 24 and 48 hours, but there was no difference in severity of perceived soreness. The use of WBV as a warm-up may mitigate DOMS but does not appear to expedite the recovery of strength in the days following eccentric exercise in resistance-trained individuals.

Although silt and clay mixtures were mostly considered to be resistant to cyclic loading due to cohesional components of their shear strength, ground failure case histories compiled from fine grained soil profiles after recent earthquakes (e.g. 1994 Northridge, 1999 Adapazari, 1999 Chi-Chi) revealed that the responses of low plasticity silt and clay mixtures are also critical under cyclic loading. Consequently, understanding the cyclic response of these soils has become a recent challenge in geotechnical earthquake engineering practice. While most of the current attention focuses on the assessment of liquefaction susceptibility of fine-grained soils, it is believed that cyclic strain and strength assessments of silt and clay mixtures need to be also studied as part of complementary critical research components. Inspired by these gaps, a comprehensive laboratory testing program was designed. As part of the laboratory testing program 64 stress-controlled cyclic triaxial tests, 59 static strain-controlled consolidated undrained triaxial tests, 17 oedometer, 196 soil classification tests including sieve analyses, hydrometer, and consistency tests were performed. Additionally 116 cyclic triaxial test results were compiled from available literature. Based on this data probability-based semi-empirical models were developed to assess liquefaction susceptibility and cyclic-induced shear strength loss, cyclically-induced maximum shear, post-cyclic volumetric and residual shear strains of silt and clay mixtures. Performance comparisons of the proposed model alternatives were studied, and it is shown that the proposed models follow an unbiased trend and produce superior predictions of the observed laboratory test response. Superiority of the proposed alternative models was proven by relatively smaller model errors (residuals).