Effect of Beetroot Juice on Anaerobic Performance and Fatigue in Adolescent Male Swimmers

This study, designed as a single-blind intervention study, was conducted in October-November 2023 with adolescent swimmers. . In determining the sample, effect size d (effect size): 1.6975 and standard deviation was taken as 4.12, and the minimum number of samples determined for Power: 0.95 and α: 0.05 in the G*Power 3.1.9 computer program was determined as seven adolescents. Adolescent swimmers with a medical condition diagnosed by a physician, following a special diet, and using regular medication were excluded from the study. Anthropometric measurements (body weight, height, body composition, skin fold measurements), freestyle time trial (TT) swimming performance test, blood lactate measurement and the Borg fatigue scale were taken.

Anthropometric Measurements Body Weight, Height, and Body Composition: The heights of the swimmers were measured with the SECA 213 brand portable stadiometer, with the feet side by side and the head on the Frankfurt plane. Body weight and composition were measured in the morning on an empty stomach, with light clothing, without shoes or socks, using a 0.1 kg sensitive TANITA MC-780 Black professional body composition device.

Skinfold Thickness Measurements: Swimmers' skinfold thicknesses were taken from the triceps, biceps, subscapular, supraspinal, abdomen, thigh, calf, chest, and midaxillary regions using Holstein brand calipers. Measurements were madein accordance with the ISAK protocol (Norton, 2018). The body fat ratio was calculated with the Foulkner (1968) equation, which was developed to calculate the body fat ratio from skinfold thickness measurements on the face.

Freestyle Time Trial (TT) Swimming Performance Test The swimmers' 8x100 m maximum effort swimming performance times were recorded with the help of a Seiko S141 300 memory stopwatch brand stopwatch with 1/100 second precision. A polar watch was attached to the swimmers' right arms, and measurements were taken every 100 m. The start of the performance was made from the sprint stone with the command (take your mark) followed by an electronic beep. 100 m freestyle swimming performance was performed by swimmers with maximum performance.

Blood Lactate Measurement: The blood lactate measurement was completed after the 8x100 m maximum effort swimming performance; blood samples taken from the finger within 10 seconds were analyzed using the Lactate Pro 2 analyzer. Lactate values were recorded in mmol/l.