## 1 Introduction
(2023) [21], however, quantified the reliability of the 3-Hop flight time, hop distance, and contact time, and reported only moderate reliability (ICC = 0.67-0.74). Assuming that this reliability is acceptable, it is important to determine whether RSI\({}_{\text{hor}}\) as a metric has a high association with performance, thereby establishing its value as a tool for athletic monitoring and exercise prescription. A recent study [21] has investigated the utility of RSI\({}_{\text{hor}}\) from a 3-Hop test, finding variable correlations with 505 test performance (\(r=-0.76\) to 0.23) and 10 m sprint performance (\(r=-0.50\) to 0.43) in male volleyball players. RSI\({}_{\text{hor}}\) measures calculated from flight and ground contact times of unilateral multiple hopping tasks have also been shown to have a negligible to moderate relationship with sprint performances, ranging from 10 to 100 m (\(r=0.00\) to \(-0.38\)) [22]. This was the first study to investigate RSI\({}_{\text{hor}}\) further than the 3-Hop test, and it noted that RSI continued to increase until the fifth hop, suggesting that a 5-Hop test should be enough multiple hops in series to understand an athlete's capability. However, further research is required to better understand the relationship between RSI\({}_{\text{hor}}\) and athletic performance, particularly in athletes accustomed to horizontal-focused movements over longer sprint distances. Interestingly, both 3-Hop and 5-Hop assessments have been used for assessing elite sprinter's training readiness for competition, and to provide key insights into \"an athlete's ability to express repeated peaks of strength in exercise with faster and faster movements\" [6,12]. According to [PERSON] [12], sprinters with good strength expression should hop seventy percent further for a 5-Hop than a 3-Hop. Whether this is the case has not been documented, and it may be that other measures, such as the RSIhor, provide better insight as to that which differentiates sprint performance. The 3-Hop is a movement that is implemented a great deal by practitioners interested in the neuromuscular function of athletes during rehabilitation and sports performance. The 5-Hop is less well researched, possibly due to the higher neuromuscular demands associated with the latter hops. The authors have noted increases of \(\sim\)56% in maximal vertical force, \(\sim\)236% in vertical braking impulse, and \(\sim\)1147% in horizontal braking impulse across steps. Given the higher neuromuscular demands, the 5-Hop may be a better differentiator of sprint ability as compared to the 3-Hop test. Based on this and the preceding information, the aims of this study were threefold: (1) to examine the relationship between 3-Hop and 5-Hop distance with sprint performance and determine whether hop kinetic variables provide stronger relationships to sprinting ability than the kinematic/hop distances; (2) to explore the relationship between two methods of determining 3-Hop and 5-Hop RSIhor and sprint performance; and (3) to investigate whether the 5-Hop/3-Hop ratio or RSIhor or other kinetic measures could differentiate between sprinters of different ability. It was hypothesized that (1) the correlations between 3-Hop and 5-Hop distances/ sprint performances would be strong and that kinetic variables would provide stronger correlations to sprinting ability; (2) both methods (flight and distance) for determining RSIhor would be similarly correlated with sprint performance; and (3) the faster sprinters would have a greater percentage difference between their 3-Hop and 5-Hop ratios. The findings will provide practitioners with valuable insights into the potential utility of multiple-hop tests for assessing, rehabbing and enhancing athletic performance.