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  • Author: Giles D. Warrington x
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John Kenny, SarahJane Cullen and Giles D. Warrington

Purpose:

“Ice-mile” swimming presents significant physiological challenges and potential safety issues, but few data are available. This study examined deep body temperature (BT), respiratory rate (RR), and swim performance in 2 swimmers completing an ice-mile swim of 1 mile (1600 m) in water less than 5°C.

Methods:

Two male cold-water-habituated swimmers completed a 1-mile lake swim in 3.9°C water. For comparative purposes, they completed an indoor 1-mile swim in 28.1°C water. The Equivital physiological monitoring system was used to record BT and RR before, during, and after each swim. Total time to complete the swims and 400-m splits were recorded.

Results:

One swimmer became hypothermic after 27 min while swimming, reaching BT of 33.7°C at swim’s end. On exiting the water the swimmers experienced large BT after-drops of –3.6°C and –2.4°C, reaching low points of 33.2°C and 31.3°C 38 and 23 min postswim, respectively. Respiratory rate and swim pace decreased over the course of the ice-mile swim for both swimmers. Swim pace for 1 swimmer declined sharply in the final 400-m lap of the ice mile when he was hypothermic. Both swimmers remained hypothermic 60 min postswim (34.2°C and 33.4°C).

Conclusion:

Ice-mile swimmers may become hypothermic while swimming, and the postswim BT after drop may expose them to dangerous levels of hypothermia. Pace and RR should be monitored as proxies for a swimmer’s physiological state. Postswim recovery should also be monitored for hypothermia for at least 1 h.

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Eimear Dolan, SarahJane Cullen, Adrian McGoldrick and Giles D. Warrington

Purpose:

To examine the impact of making weight on aerobic work capacity and cognitive processes in a group of professional jockeys.

Methods:

Nine male jockeys and 9 age-, gender-, and BMI-matched controls were recruited to take part in two experimental trials, conducted 48 hr apart. The jockeys were asked to reduce their body mass by 4% in the 48 hr between trials, and controls maintained usual dietary and physical activity habits between trials. Aerobic work capacity was assessed by performance during an incremental cycle ergometer test. Motor response, decision making, executive function, and working memory were assessed using a computerized cognitive test battery.

Results:

The jockey group significantly reduced their body mass by 3.6 ± 0.9% (p < .01). Mean urine specific gravity (Usg) readings increased from 1.019 ± 0.004–1.028 ± 0.005 (p < .01) following this reduction in body mass. Peak work capacity was significantly reduced between trials in the jockey group (213 ± 27 vs. 186 ± 23 W, p < .01), although VO2peak (46.4 ± 3.7 vs. 47.2 ± 6.3 ml·kg·min-1) remained unchanged. No changes were identified for any cognitive variable in the jockey group between trials.

Conclusion:

Simulation of race day preparation, by allocating a weight that is 4% below baseline body mass caused all jockeys to report for repeat testing in a dehydrated state, and a reduction in aerobic work capacity, both of which may impact on racing performance.

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Frank Nugent, Thomas Comyns, Alan Nevill and Giles D. Warrington

Purpose: To assess the effects of a 7-wk low-volume, high-intensity training (HIT) intervention on performance parameters in national-level youth swimmers. Methods: Sixteen swimmers (age 15.8 [1.0] y, age at peak height velocity 12.9 [0.6] y, 100-m freestyle 61.4 [4.1] s) were randomly assigned to an HIT group or a low-intensity, high-volume training (HVT) group that acted as a control. The HIT group reduced their weekly training volume of zone 1 (low-intensity) training by 50% but increased zone 3 (high-intensity) training by 200%. The HVT group performed training as normal. Pretest to posttest measures of physiological performance (velocity at 2.5- and 4-mM blood lactate [velocity2.5mM and velocity4mM] and peak blood lactate), biomechanical performance (stroke rate, stroke length [SL], and stroke index [SI] over a 50- and 400-m freestyle), and swimming performance (50-, 200-, and 400-m freestyle) were assessed. Results: There were no significant 3-way interactions between time, group, and sex for all performance parameters (P > .05). There was a significant 2-way interaction between time and group for velocity4mM (P = .02, ηp2=.40), SL50 (P = .03, ηp2=.37), and SI50 (P = .03, ηp2=.39). Velocity4mM decreased in the HIT group but increased in the HVT group while SL50 and SI50 decreased in the HVT group. Conclusions: A 7-wk HIT intervention was neither beneficial nor detrimental to performance parameters; however, the HIT group completed 6 h (17.0 km) of swimming per week compared with 12 h (33.4 km) per week for the HVT group.

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Ciara Sinnott-O’Connor, Thomas M. Comyns, Alan M. Nevill and Giles D. Warrington

Context: Stress responses in athletes can be attributed to training and competition, where increased physiological and psychological stress may negatively affect performance and recovery. Purpose: To examine the relationship between training load (TL) and salivary biomarkers immunoglobulin A (IgA), alpha-amylase (AA), and cortisol across a 16-wk preparation phase and 10-d competition phase in Paralympic swimmers. Methods: Four Paralympic swimmers provided biweekly saliva samples during 3 training phases—(1) normal training, (2) intensified training, and (3) taper—as well as daily saliva samples in the 10-d Paralympic competition (2016 Paralympic Games). TL was measured using session rating of perceived exertion. Results: Multilevel analysis identified a significant increase in salivary immunoglobulin A (sIgA: 94.98 [27.69] μg·mL−1), salivary alpha-amylase (sAA: 45.78 [19.07] μg·mL−1), and salivary cortisol (7.92 [2.17] nM) during intensified training concurrent with a 38.3% increase in TL. During the taper phase, a 49.5% decrease in TL from the intensified training phase resulted in a decrease in sIgA, sAA, and salivary cortisol; however, all 3 remained higher than baseline levels. A further significant increase was observed during competition in sIgA (168.69 [24.19] μg·mL−1), sAA (35.86 [16.67] μg·mL−1), and salivary cortisol (10.49 [1.89] nM) despite a continued decrease (77.8%) in TL from the taper phase. Conclusions: Results demonstrate that performance in major competition such as Paralympic games, despite a noticeable reduction in TL, induces a stress response in athletes. Because of the elevated stress response observed, modifications to individual postrace recovery protocols may be required to enable athletes to maximize performance across all 10 d of competition.