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

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 (DSIST50–100–150–200 m) and its preliminary agreement with the 7 × 200 m incremental step test (IST7 × 200 m) in trained male university swimmers. Ten trained male university swimmers completed pool-based field testing, including the IST7 × 200 m, DSIST50–100–150–200 m, and a supportive 200 m freestyle time trial. The main DSIST50–100–150–200 m –IST7 × 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. Mean swimming velocity was close between the DSIST50–100–150–200 m and IST7 × 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 DSIST50–100–150–200 m and IST7 × 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. The DSIST50–100–150–200 m was feasible and showed preliminary agreement with the IST7 × 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 DSIST50–100–150–200 m should not be considered a direct substitute for the IST7 × 200 m or a criterion measure of aerobic capacity. Larger studies with repeated trials, counterbalanced test orders, and physiological criterion measures are needed. The DSIST50–100–150–200 m is a short, lower-volume pool-based protocol for applied swimming monitoring. The protocol was feasible in trained male university swimmers and was completed by all participants. Swimming velocity and selected stroke-mechanics outcomes showed stronger preliminary agreement with the IST7 × 200 m. HRpeak, RPE, and lactate-change responses should be interpreted as protocol-specific internal-load indicators. The DSIST50–100–150–200 m may support practical field monitoring when reduced testing burden is required, but it should not replace physiological criterion testing.