Neuromuscular Responses by Contact Time and Reactive Force Index during Fall Times
Abstract
Several studies have investigated neuromuscular variables, such as ground contact time and the reactive strength index (RSI), during the execution of the drop jump (DJ). However, detailed individual-level analyses, as well as comparisons of contact time between the drop jump and the depth jump (DeJ), remain scarce in the literature. Therefore, the aim of this study was to compare neuromuscular responses through ground contact time and the reactive strength index at different drop heights. This was a single-case, analytical observational study with a cross-sectional design conducted with a female 100-m sprinter. DJ and DeJ trials were performed from heights of 40, 60, and 70 cm using a contact mat. The results indicated a very strong and statistically significant negative correlation between ground contact time and the reactive strength index at the 60-cm height. Furthermore, a statistically significant difference between DJ and DeJ was identified only at the 60-cm height. It was concluded that the 60-cm height exhibited the most pronounced indicators of reactive performance, characterized by the association between shorter ground contact times and higher RSI values, as well as by the significant difference between DJ and DeJ. In the athlete evaluated, drop height influenced ground contact time during the DJ and RSI values, but not ground contact time during the DeJ.
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