Hébert-Losier, KimNgawhika, Te ManawaBalsalobre-Fernandez, CarlosO'Neill, Seth2023-11-092023-11-092023-11-011466-853Xhttps://hdl.handle.net/10289/16126Objectives: To examine the strength of the relationship between plantarflexor power and strength-endurance metrics and 10-m sprint times in male Rugby Union players. A secondary aim was to examine the strength of the relationship within calf muscle metrics. Design: Observational cross-sectional correlational. Setting: Field-based. Participants: Sixteen male Rugby Union players in the National Provincial Championship. Main outcome measures: Participants completed three single-leg calf muscle tests: bodyweight power, weighted power, and strength-endurance. Data were recorded using the Calf Raise application. Three-to-four days later, average and best 10-m sprint performances were collected using timing lights. Results: There were large significant correlations between 10-m sprint performances (average and best times) and calf muscle power (weighted) and strength-endurance (total displacement and work) metrics (r = −0.503 to −0.628). There were large significant correlations between bodyweight and weighted power, weighted power and strength-endurance (total displacement and work), and most strength-endurance metrics (r = 0.520 to 0.943). Conclusions: Our findings emphasise the importance of triceps surae muscle power and strength-endurance for maximal-effort accelerations and sprint performances in Rugby Union. Our data indicate that weighted power and total work from strength-endurance tests are the most useful metrics for further investigation in the context of short sprints and acceleration.en© 2023 Elsevier B.V. This is an author’s accepted version of an article published in Physical Therapy in Sport.Journal Article10.1016/j.ptsp.2023.09.0011873-1600