A More Thorough Analysis of the Countermovement Jump Demonstrates Changes in Neuromuscular Performance During Pre and Early Competitive Season in Elite Futsal Players

This study aimed to investigate the variations on vertical jump and sprint performance during the first weeks of a futsal season. Eleven elite futsal players, competing in Spain’s 1st division over the season 2019–2020, performed two countermovement jumps (CMJ) on a force platform and a sprint test of 10-m at three different timepoints: before the pre-season; immediately after the pre-season; and early in-season. A one-way repeated measure ANOVA with post-hoc pairwise comparisons and effect sizes (ESs) were used. Non-significant and trivial changes were observed in CMJ height (p = 0.830; ES = 0.12) among the three timepoints. However, significant and moderate positive changes among seasons were found in specific CMJ kinetic variables such as: modified reactive strength index (p = 0.011; ES = 0.60), eccentric (Ecc) peak force (p = 0.011; ES = 0.65), Ecc deceleration rate of force development (p = 0.008; ES = 0.60), Ecc duration (p = 0.040; ES = 0.89), and concentric (p = 0.030; ES = 0.45) and landing peak force (p = 0.012; ES = 0.68). A significant time interaction was observed in sprint performance (p = 0.038; ES = 0.58); however, non-significant and small-moderate changes were detected in sprint time when compared among periods. In conclusion, CMJ kinetic variables should be incorporated and analyzed alongside more standard measures (CMJ height) to monitor performance in elite futsal players, as changes of substantial magnitude were observed in phase-specific metrics during the pre-season and the initial stages of the competitive calendar.