2023, Volume 19
Heat stress levels in judokas during a special performance test conducted at two different ambient temperatures
Tomasz Pałka1, Lukasz Rydzik1, Kazimierz Witkowski2, Lukasz Tota1, Grzegorz Lech1, Tadeusz Ambroży1, Alejandro Leiva-Arcas3, Rafał Kubacki2, Anna Piotrowska1, Wojciech Wąsacz1, Wojciech Czarny4
1University of Physical Education in Krakow, Kraków, Poland
2University of Physical Education in Wrocław, Wrocław, Poland
3Universidad Católica de Murcia, Murcia, Spain
4University of Rzeszow, Rzeszow, Poland | Department of Sports Kinanthropology, Faculty of Sports, Universtiy of Prešov, Prešov, Slovak Republic
Author for correspondence: Lukasz Rydzik; University of Physical Education in Krakow, Kraków, Poland; email: firstname.lastname@example.org
Background and Study Aim: The exercise metabolism of a judoka during a tournament bout or a single training unit is based primarily on anaerobic processes. Under such conditions of physical stress, significant damage to muscle cells occurs, greater than in typically aerobic efforts. Among the strongest stimuli causing these changes are the mechanical and metabolic stresses associated with the physiological cost of exercise, which can be exacerbated when working at elevated ambient temperatures. The aim of our research was to obtain knowledge about the relationship between the effect of a special fitness test conducted at two different ambient temperatures and the level of heat stress in judokas.
Material and Methods: The study was carried out among a group of 15 professional judo athletes aged 20.65 ±2.03 years with an average aerobic capacity level. The research protocol consisted of two main parts with separate tasks. Part one was the preliminary study (stage I, II and III), and part two was the main study (stage IV and V). The performance tests were conducted during the starting period and took place in a thermoclimatic chamber and an air-conditioned laboratory. In Stage I, selected anthropometric and circulatory indicators were measured. Stage II involved the male subjects performing an exercise test assessing anaerobic and aerobic capacity with the lower limbs (LL) and after seven days with the upper extremities (AA) (stage III). The Wingate test for lower limbs (LL) and upper limbs (AA) was used to assess anaerobic capacity indices. After a minimum of 2h after completing the Wingate Test, the subjects took a test to assess aerobic capacity. To assess aerobic capacity, a direct method was used – a test with gradually increasing load performed on a cycloergometer to refusal to continue due to extreme fatigue. The test determined physiological indicators at the level of the second ventilation threshold (VT2) and at the maximum level (VO2max). In the main study (stage IV and V), half of the male subjects performed 5 restrictive pulse exercise sequences on a foot cycloergometer and hand cycloergometer in a thermoclimatic chamber at 21 ±0.5°C (stage IV) and the other half at 31 ±0.5°C (stage V), relative humidity 50% ±5%. After the seven days the subjects rejoined stages IV and V. This time, the first group of subjects performed the exercise at 31 ±0.5°C and the second half at 21 ±0.5°C. The interval effort was characterized by pulsatile, alternating, time-varying loading of the upper and lower extremities during anaerobic exercise series punctuated by 15-minute rest intervals.
Results: In the Wingate test with the lower extremities, the maximum anaerobic power (RPP) was 12.12 ±0.87 W ∙ kg−1, and with the upper extremities it was 7.00 ±0.56 W ∙ kg−1. Total work (TW) in the test with the lower extremities was 21.85 ±4.26 kJ and with the upper extremities 13.36 ±2.50 kJ. The result of VO2max measurement for the lower limbs averaged 43.23 ±7.79 ml.kg−1 ∙ min−1, and for the upper limbs 37.19 ±5.26 ml.kg−1 ∙ min−1. HRmax recorded in the graded test for the lower limbs averaged 185 ±8.19 bpm and for the test for the lower limbs: 183 ±8.43 bpm. The time to reach VT2 averaged 11.50 ±3.09 min for the lower extremities and 8.32 ±2.99 min for the upper extremities. At the second ventilation threshold, the heart rate of contraction (HRVT2) was 168 ±8.42 bpm (LL) and 162 ±8.75 bpm (AA). The percentage of oxygen uptake at the second ventilation threshold (%VO2max) was 77.68 ±9.61% (LL) and 71.88 ±11.65% (AA), respectively. As a result of exercise dehydration at 21°C and 31°C, there was a statistically significant reduction in body weight (p<0.05). However, there was no statistically significant difference between the BM values recorded after a series of exercise at 21°C and 31°C. PSI and CHSI values were statistically significantly higher for exercise performed at 31°C.
Conclusions: Different ambient thermal conditions do not affect the volume of work performed in pulsatile anaerobic exercise, which does not support the view represented by some researchers about the effect of ambient temperature on anaerobic capacity. The tested athletes tolerated the thermal load well and their subjective assessment of the strenuousness of the work, did not differ in the ambient temperatures used. The greater weight loss, and thus dehydration, observed in athletes after exercise at elevated ambient temperatures may be related to a widening of their capillary network in both muscle and skin, influenced by years of training, which also increases the body's water percentage which promotes sweat transpiration. In order to increase the body's tolerance to heat and exercise stress, it is reasonable in professional judokas to conduct training under various ambient thermal conditions.
Key words: aerobic capacity, anaerobic performance, combat sports, thermoclimatic chamber