Evaluation of ultrasound velocity to assess the hydration status of wrestlers

The objective of this study was to evaluate the utility of ultrasound velocity (UV) to detect changes in the hydration status of wrestlers after undergoing acute dehydration and a 2-hour rehydration period. Forty-seven NCAA wrestlers (mean+/-SEM); age 19.1+/-0.2 years, height 1.73+/-0.1 m, body mass (BM) 79.4+/-2.4 kg were tested in euhydrated, dehydrated, and a 2-hours rehydrated conditions. Hydration status was quantified by measuring changes in plasma osmolarity (Posm), urine osmolarity (Uosm), urine specific gravity (Usg), and BM. Ultrasound velocity was measured at 1 MHz using 1.5-microsecond duration tone burst in the soleus muscle. Significant changes (p<0.001) in UV during periods of dehydration (BM change=-3.6+/-0.14%) (UV=+2.18 m.s) and rehydration (BM change=+2.8+/-0.12%) (UV=-2.89 m.s) were found. Significant main effects (p<0.001) were also found for Usg, Uosm, and Posm during dehydration. The change in Posm from the 1 to 2-hour rehydration time period significantly correlated to the change in UV during the same time period (r=0.27, p<0.001). This study demonstrates that changes in UV correspond to the changes of Posm, Usg, Uosm, and BM during acute dehydration and rehydration in collegiate wrestlers. The use of ultrasound measures may have potential application as an alternative field-based method to assess the hydration status of collegiate wrestlers although future research is warranted.