Reliability of the maximal resisted sprint load test and relationships with performance measures and anthropometric profile in female field sport athletes
Resisted sled sprint (RSS) training is an effective modality for the improvement of linear sprint speed. Previous methods of RSS load prescription e.g. an absolute load or as a percentage of body mass (%BM), do not account for inter-individual differences in strength, power or speed characteristics, although the 'maximum resisted sled load' (MRSL) method of RSS load prescription may provide a solution. MRSL is defined as the final RSS load before an athlete can no longer accelerate between two phases (10-15 m and 15-20 m) of a 20 m linear sprint. However, the MRSL test has not been analysed for reliability. Additionally, MRSL performance has not been compared to the outcome of other performance tests. The primary aim of this study was to investigate the reliability of the MRSL testing protocol in female field sport athletes. Participants (age, 20.8 ± 1.9 y; body mass, 64.3 ± 8.4 kg; height, 1.66 ± 0.65 m) tested for anthropometric measurements, strength and power performance testing and twice for MRSL. MRSL values ranged from 20.7 to 58.9%BM. MRSL test-retest reliability intraclass correlation coefficient, confidence intervals and coefficient of variations were 0.95, 0.85-0.98 and 7.6%, respectively. MRSL was 'moderately' and 'strongly' correlated with a number of anthropometric and performance tests (p < 0.05) including % fat free mass, countermovement jump, loaded countermovement jump, rate of force development, horizontal jump and horizontal bound performance. MRSL is a reliable measure for determining the RSS load at which an individual can no longer accelerate during a single RSS effort over 0-20 m. MRSL also accounts for inter-individual variation in body composition, power and speed characteristics of female field sport players.