Reliability and Concordance of 15-metre (15-m) Sprint Performance on Sand and Firm Surfaces

This observational repeated-measures methodological study evaluated the reliability and agreement of a 15-m linear sprint test performed on sand and firm surfaces in male beach-sport athletes. Participants completed three maximal sprint attempts on each surface during up to two testing sessions conducted on separate days. The study examined trial-to-trial reliability within each session, stability between testing days, and concordance between sprint times obtained on sand and firm surfaces. No therapeutic or training intervention was administered. Sand and firm surfaces were used exclusively as assessment conditions.

Inclusion Criteria * Male athlete participating in beach soccer, beach volleyball, or beach handball. * Minimum of six months of regular beach-sport training. * Able to complete maximal 15-m sprint assessments on sand and firm surfaces. * Provision of written informed consent before participation. Exclusion Criteria * Musculoskeletal injury during the six weeks preceding testing. * Acute illness during the seven days preceding testing. * Failure to complete at least one full testing session.