Upper Limbs Movement Frequency: Connection to Swimming Performance and Kinematics.

Background: Stroke rate (SR) is a critical determinant of swimming speed and performance; however, the relationship between upper-limb movement frequency assessed on land and SR in water remains unclear. Methods: This preliminary study examined the association between dry-land upper-limb movement frequency and in-water kinematics in ten male competitive swimmers (15.23 ± 1.06 years). Dry-land upper-limb movement frequency was evaluated through two maximum-effort trials consisting of 10-12 circular arm movements performed under a straight-arm condition (STRSR) and a swimming-technique-simulated bend-arm condition (TECHSR). All trials were video-recorded for analysis. In-water testing included a maximum-effort 50 m sprint and 8-12 × 25 m progressively increasing speed tests to elicit maximum swimming speed and maximum SR. SR, swimming speed, stroke length, and stroke index were calculated for all trials. Results: No relationship was observed between dry-land upper-limb movement frequency and SR of the 50 m test (p > 0.05). However, the percentage difference between STRSR and maximum SR was associated with stroke index at maximum speed (r = -0.66, p = 0.04), maximum SR (r = -0.65, p = 0.04), and swimming speed at maximum SR (r = -0.72, p = 0.01) οf the 8-12 × 25 test. Similarly, TECHSR was correlated with stroke index at maximum speed, SR, and stroke length in the 8-12 × 25 test (r = -0.67 to -0.71, p = 0.01). Conclusions: These findings suggest that faster and more efficient swimmers exhibit a greater difference between their maximum dry-land movement frequency in upper limbs and the SR adopted in water, allowing a greater potential to adjust in a more comfortable and submaximal manner in water movements.