Author(s): PETROVIC, M., HAFSTEINSSON, T., GISLADOTTIR, T., Institution: UNIVERSITY OF ICELAND, Country: ICELAND, Abstract-ID: 2228

INTRODUCTION:
The reactive strength index (RSI) is a ratio of input to output – the input is represented by time spent on the ground generating the force to perform a countermovement jump (CMJ), and the output is the height of the jump. The RSI holds particular relevance in cycling, serving as a crucial indicator of an athletes capacity for explosive power output during pedal strokes. There is very limited research in this area of cycling. Still, generally, it has been known that there is a significant correlation between RSI and strength performance tests, indicating that superior strength levels can enhance an athletes capacity for rapid force production during efforts. Integrating RSI assessments alongside traditional strength tests provides a comprehensive understanding of an athletes potential to excel in cycling disciplines requiring bursts of power. We hypothesised that there will be a strong association between RSI measurements and performance in cycling-specific strength tests, highlighting its importance in assessing a cyclists ability to generate rapid force during crucial moments of acceleration and climbing. This article aimed to establish the correlation between the RSI and certain metrics involving strength and power production off lower limb
METHODS:
Seven male cyclists, members of the youth national team of Iceland (age: 18.9 ± 0.9 years; body weight: 77.7 ± 4.6 kg, body height: 182 ± 3.6 cm) participated in this study. The cyclists underwent a comprehensive series of biomechanical assessments encompassing various metrics: countermovement jump, drop jump (DJ), isometric mid-thigh pull (IMTP) measured on the force plates, as well as measurements of Nordic hamstring and hip abduction and adduction strength by using dynamometers. Knee extension and flexion were measured on an isokinetic dynamometer. Data were imported in Jamovi software and Pearson correlation was run to establish to relationship between the variables.
RESULTS:
A significant positive correlation has been observed between the RSI and knee flexion and extension peak torque/BW at 60 degrees per second, CMJ Jump Height, CMJ Concentric Peak Force/BM, DJ Jump Height, DJ Peak Power/BM, DJ Concentric Peak Velocity, DJ RSI, IMTP Force at 200ms/BM, IMTP Peak Vertical Force/BM, Nordic hamstring Force/BW.
CONCLUSION:
The significant positive correlation observed between the RSI and various measures of strength and power underscores the importance of RSI in enhancing cycling performance. These findings suggest for the first time that improving RSI may contribute to enhanced cycling-specific power production and overall athletic performance, emphasizing its relevance as a key metric for cyclists aiming to optimize their training strategies. Incorporating RSI-focused training methodologies could potentially lead to improved sprinting capabilities, climbing efficiency, and overall cycling performance.