Comparing Differences and Relationships Between Traditional and Resisted Sprints in Elite Youth Rugby Backs and...

We tested the differences in maximum strength and various parameters of sprint performance between youth backs and forwards. Additionally, we examined the associations among various strength-sprint measures, as well as between unresisted and heavy resisted sprints.

Thirty-two youth rugby players were assessed at the beginning of the season with the following tests: unresisted and resisted (50% body mass) 30-m sprints and 1-repetition maximum (1RM) in the squat exercise. Body mass, sprint velocity, and 1RM values were compared between backs and forwards using an independent t test. Pearson product-moment correlation was used to assess the relationships between absolute and relative 1RM values (rel1RM) and unresisted and resisted sprints.

Youth backs outperform forwards in terms of maximum velocity and under resisted sprinting conditions. Furthermore, backs exhibit higher levels of rel1RM compared with forwards. Our findings indicate significant correlations between resisted and unresisted sprinting for several sprint qualities when considering all players together. When participants were divided into different groups, stronger correlations between resisted and unresisted sprints were found among slower/heavier players (forwards). Notably, for faster players (backs), there was no significant correlation between heavy resisted sprints and maximum velocity (r = .25; P = .4). Last, despite their lower rel1RM values compared with backs, for forwards the rel1RM is closely associated with unresisted and resisted sprints.

Unlike youth forwards, for youth backs, the ability to sprint faster with heavy sled loads is not associated with the maximum velocity achieved in linear sprints, and higher values of rel1RM do not necessarily lead to improved sprint performance.