The gold rush in para swimming: changes in the speed curve of a visually impaired world and paralympic champion - a case study.

This case study examined the association between 50 m freestyle and speed curve parameters of a world-class Paralympic swimmer and analysed the changes in speed curves and their frequency components across her performance levels. From 2018 to 2021, a visually impaired female swimmer (26.59 s in 50 m freestyle, S12 class) underwent 22 tests to obtain instantaneous speed synchronised with video recording. She regularly performed 50 m freestyle in competitions and time trials. The fast Fourier transformation method converted the speed signal into frequency domains and determined the relative contribution of the harmonics with two maxima and minima (H2, arms actions) and six maxima and minima (H6, legs actions). The functional paired t-test compared the speed curves at the beginning (PRE) and end (POST) of the analysed period. The 50 m freestyle time correlated with average speed (r = -0.50, p = 0.02). The contribution of H6 increased in the first year and remained large, whereas the contribution of H2 was lower throughout the whole period. POST was faster than PRE in five moments that coincide with the downward leg kick moments. These changes allowed her to stay longer at the upper part of the curve and improve performance over time.

Predicting the individual lactate minimum speed by T10 and T30 in swimming.

BACKGROUND: This study investigated the relationship between the lactate minimum (LACmin) and the 10- (T10) and 30-min (T30) continuous tests in swimmers. METHODS: Twelve swimmers (78.1±3.1% of the world record) performed the LACmin (hyperlactatemia: 2×50 m all-out 8-min apart, incremental part: N.×300 m 30-s apart), T30 and T10 using the front-crawl stroke. Blood samples were collected after each stage of LACmin for lactate analysis. Swimmers were oriented to swim as fast and as constant as possible in T10 and T30. RESULTS: Speeds in T10 (1.28±0.10 m/s) and T30 (1.21±0.09 m/s) were different from LACmin (1.24±0.09 m/s). T10 and T30 speeds presented a nearly perfect relationship with LACmin and acceptable prediction errors (T10: r=0.938, P<0.001, 0.033 m/s; T30: r=0.927, P<0.001, 0.036 m/s, respectively). CONCLUSIONS: T10 and T30 can be used as indirect tests for evaluating LACmin in swimming.

Long-term changes in the speed curve of a world-class butterfly swimmer.

This study describes the changes in selected points of the speed curve, stroke rate (SR), and stroke length (SL) of an elite butterfly swimmer and examines their relationship with average speed (AS) and competitive performance. Over eight years, a male swimmer (50 and 100 m: 22.70 and 51.47 s) underwent 18 tests to assess AS, SR, SL, intracyclic speed variation (ISV), and eight selected points of the speed curve. Peak1 is the maximum speed in the upward kick executed during the arm recovery; peak2 is the maximum speed in the first downward kick after the arm entered into the water; peak3 is the maximum speed during the arm pull; and peak4 is the maximum speed during the arm push combined with the second downward kick. Min1, min2, min3, min4 corresponds to the minimum speeds found respectively before each peak speed. Official competitive results in 50 (50BF) and 100 m (100BF) within three weeks of the speed tests were registered. SR (r=0.736), ISV (r=-0.493), peak1 (r=0.555), min2 (r=0.558), and min3 (r=0.539) were correlated with AS. 50BF was correlated with AS (r=-0.658) and peak1 (r=-0.820), whereas 100BF with AS (r=-0.676), SR (r=-0.571), peak1 (r=-0.758), and peak2 (r=-0.594). AS increased by improving SR, peak1 and peak3. Increases in min2 and min3 indicate better transitions from resistive to propulsive phases. Selected points of the speed curve may predict butterfly performance.

Does a 4-week training period with hand paddles affect front-crawl swimming performance?

This study investigated the effects of a 4-week training with hand paddles (HPD) on front-crawl swimming performance (SP), clean swimming speed (SPEED), stroke rate (SR), stroke length (SL) and tethered force (TF). Twenty swimmers (10 men and 10 women) were paired according to performance and gender, and were randomly assigned to control (CON, 22.4 ± 2.3 years) or HPD (21.8 ± 1.9 years) groups. During 4 weeks both groups performed the same training, except for a sprint training set (3 times/week, 10 × 10 strokes all-out, 1-min rest) completed with (HPD = 320 cm2) and without (CON) paddles. Afterwards, both groups performed the same training over a 2-week taper period. SP, SPEED, SR, SL and TF were assessed before (PRE) and after the 4-week period (POST), after the first (T1) and second taper weeks (T2). Swimmers rated their perceived exertion for the sprint training set (RPETS) and the training session for determining internal training load (ITL). SP, SPEED, SR, SL and TF did not change from PRE to POST, T1 and T2. ITL and RPETS were not different between groups. Training 4 weeks with HPD does not affect swimming performance, so the use of HPD remains unsupported in such period.

Effect of hand paddles and parachute on the index of coordination of competitive crawl-strokers.

We investigated the effects of hand paddles and parachute on the relative duration of stroke phases and index of coordination of competitive crawl-strokers. Eleven male-swimmers (age: 21.9 ± 4.5 years; 50-m best time: 24.23 ± 0.75 s) were evaluated in four maximal-intensity conditions: without equipment, with hand paddles, with parachute, and with both hand paddles and parachute. Relative stroke phase duration of each arm, swimming velocity, and stroke rate were analysed from video (60 Hz). The index of coordination was quantified based on the lag time between propulsive phases of each arm, which defined the coordination mode as catch-up, opposition or superposition. The stroke rate decreased in all conditions (P < 0.05) and swimming velocity decreased with parachute and with paddles + parachutes (P < 0.05). The coordination mode changed from catch-up in free swimming (-2.3 ± 5.0%) to opposition with paddles (-0.2 ± 3.8%), parachute (0.1 ± 3.1%), and paddles + parachute (0.0 ± 3.2%). Despite these variations, no significant differences were observed in relative duration of right and left arm-stroke phases, or in index of coordination. We conclude that the external resistances analysed do not significantly influence stroke phase organization, but, as a chronic effect, may lead to greater propulsive continuity.