Feasibility and preliminary agreement of a lower-volume, pool-based incremental swimming protocol in trained male university swimmers: a pilot study.

Background: Lower-volume pool-based protocols may help coaches and sport scientists monitor selected swimming responses with less disruption to routine training. This pilot study examined the operational feasibility of the Distance and Speed Incremental Swimming Test (DSIST 50-100-150-200 m ) and its preliminary agreement with the 7 × 200 m incremental step test (IST 7 × 200 m ) in trained male university swimmers.

Methods: Ten trained male university swimmers completed pool-based field testing, including the IST 7 × 200 m , DSIST 50-100-150-200 m , and a supportive 200 m freestyle time trial. The main DSIST 50-100-150-200 m -IST 7 × 200 m comparison focused on corresponding 200 m efforts. Completion time, swimming velocity, stroke-mechanics variables, highest recorded post-exercise heart rate, post-exercise blood lactate concentration ([La⁻]post), lactate change (Δ[La⁻]), and rating of perceived exertion (RPE) were assessed. Paired comparisons used the Wilcoxon signed-rank test with Holm adjustment. Preliminary agreement was evaluated using intraclass correlation coefficients (ICC) and Bland-Altman analysis.

Results: Mean swimming velocity was close between the DSIST 50-100-150-200 m and IST 7 × 200 m protocols (1.41 ± 0.12 vs. 1.39 ± 0.12 m·s⁻¹), with no Holm-adjusted evidence of a systematic difference. Swimming velocity showed good preliminary agreement (ICC (2,1) = 0.81) and a small mean bias (0.018 m·s⁻¹; limits of agreement: -0.124 to 0.160 m·s⁻¹). Completion time showed poor agreement (ICC (2,1) = 0.26) and wide limits of agreement (- 30.0 to 14.4 s). Kinematic outcomes showed stronger agreement estimates, with ICC values of 0.81-0.94. Highest recorded post-exercise HR was not significantly different between different between the DSIST 50-100-150-200 m and IST 7 × 200 m protocols (181.0 ± 3.36 vs. 184.8 ± 6.8 beats·min⁻¹; Holm-adjusted p = 1.00) but showed poor agreement. [La⁻] post and RPE showed moderate agreement, whereas Δ[La⁻] showed poor agreement.

Conclusion: The DSIST 50-100-150-200 m was feasible and showed preliminary agreement with the IST 7 × 200 m for swimming velocity and selected segment-based stroke-mechanics outcomes. Its lower-volume structure may support practical monitoring of selected performance and technical indicators with reduced testing burden. However, weaker agreement for completion time, HRpeak, and lactate-change responses indicates that the DSIST 50-100-150-200 m should not be considered a direct substitute for the IST 7 × 200 m or a criterion measure of aerobic capacity. Larger studies with repeated trials, counterbalanced test orders, and physiological criterion measures are needed.