International SportMed Journal - Volume 11, Issue 3, 2010
Volume 11, Issue 3, 2010
Physiological determinants of performance in breaststroke swimming events : original research articleSource: International SportMed Journal 11, pp 324 –335 (2010)More Less
Background: The comprehension of the relationships between physiological parameters and swimming performance in Breaststroke events seems not to be fully understood. Research question: The aim of this study was to correlate aerobic and anaerobic physiological measurements with the performance in 100m and 200m breaststroke. This performance was determined either with the subjects' performance in 100m and 200m simulated breaststroke events with the Aquatrainer valve and with the subjects' season best performance in true competitions. Methods: Twenty two male swimmers involved in systematic training and competition programmes participated in this study. The swimmers were divided in two groups (10 for 100m group and 12 for 200m group). The swimmers' personal best performance for the 100m and the 200m breaststroke was converted according to the FINA table. The subjects performed a graded swimming test and an all-out test on different days. Throughout all testing expired gases were collected breath by breath and analysed with a K4b2 Gas Analyser connected to an AquaTrainer Valve to determine different physiological parameters. Capillary blood samples were also collected from the finger to determine the blood lactate concentration after each boot. The subjects' performance during the all-out tests was taken as dependent variable and the physiological measures were defined as independent variables. Results: The performance during the all-out bout correlated with the season best FINA score (r = 0.52; p<0.05). The best season performance was more accurately predicted by the combination of aerobic fraction of energy release, peak blood lactate post-exercise and VO2 elicited at the swimming velocity corresponding to the 2mmol.L-1 threshold for the 200m event (imprecision ≈5%), while in the 100m event it was best predicted by the combination of estimated body fat, VO2 elicited at the swimming velocity corresponding to the 4mmol.L-1 threshold and peak VO2 (imprecision ≈3%). Conclusions: Physiological testing with direct VO2 measurement and blood lactate assessment may provide some insights into the performance ability of breaststroke swimmers, namely by the assessment of peak VO2 and both sub-maximal and supra-maximal blood lactate.
Source: International SportMed Journal 11, pp 336 –344 (2010)More Less
The aim of this study was to compare the heart rate responses of infants performing different basic aquatic motor skills. The sample included 14 infants of 13.7 ± 7.5 months-old and 7.71 ± 7.54 months. Heart rate was assessed with a heart rate monitor adjusted around the infant's chest. The basic aquatic motor skills were: (i) accompanied displacement in a prone position; (ii) accompanied displacement in a back position; (iii) vertical position; (iv) submersion; (v) jumps; (vi) displacement with material; (vii) autonomous displacements. The Friedman test verified a significant difference in heart rate according to the aquatic motor skills performed. Mean rank order from the highest to the lowest value was respectively the heart rate value during immersion, jumps, displacement in prone position, autonomous displacement, vertical position, displacement with equipment aid and displacement in back position. The average heart rate of the full session and the maximal heart rate presented significant associations with infant's age and background during the swim sessions. Thus the heart rate's acute response was dependent on the type of motor skill being performed.
The relationship between physical activity level and fatigue in vocational college students : original research articleSource: International SportMed Journal 11, pp 345 –355 (2010)More Less
Objectives: The specific objectives of this study were: 1) to estimate the prevalence rate of fatigue and physical activity level and 2) to examine the relationship between these two variables among vocational college students. Design: This cross-sectional research was done with a ½ sampling method of 186 students at a vocational college. As a data-collecting device, the Physical Activity Assessment Questionnaire (PAAQ), the International Physical Activity Questionnaire (IPAQ) and Fatigue Severity Scale (FSS) were used. An additional questionnaire was administered to obtain demographic data. Results: The prevalence rate of fatigue was 55.9%. The average weekly energy consumption of the students calculated in terms of IPAQ total was 1223.52±1194.80MET-min/week; in terms of the PAAQ total, it was 10401.35±9925.2kcal/week. The average weekly energy consumption of the students calculated in terms of the IPAQ total was 1016.13±1222.89MET-min/week for the fatigue group; and in terms of the PAAQ total, it was 9042.74±4954.55kcal/week. When the whole group was catagorised according to their IPAQ total score, 55.9% (104) of them were determined to be inactive, 34.9% (65) were minimally active and 9.1% (17) were active. When the whole group were categorised according to their PAAQ total score, 91.8% (171) were sedentary, 2.4% (2) were active and 4.8% (4) were very active. Except for the PAAQ stair and PAAQ school variables, from the perspective of other variables of physical activity measurement, a statistical difference between the fatigued and non-fatigued groups was seen (p<0.05). There was a negative correlation between physical activity and fatigue (p< 0.05). Conclusions: Vocational college students demonstrated a high prevalence rate of fatigue and their level of physical activity was clearly low. The results of this study indicated that physical activity significantly correlated with the prevalence of fatigue. In order to maintain and improve the health of college students, training, support and opportunity to increase their level of physical activity should be provided.
Plasma levels of leptin in overweight adults undergoing concurrent training : original research articleSource: International SportMed Journal 11, pp 356 –362 (2010)More Less
Objective: To assess the acute effects of concurrent training (CT) on plasma leptin levels in overweight adults. Material and methods: Quasi-experimental research methods were used. A sample of twenty individuals (27.7 ± 5.1 years-old, BMI 27.08±1.42) was randomly divided between the experimental group (EG: n=10) and the control group (CG: n=10). After subjects had fasted for 12 hours, blood samples were collected from both groups, and plasma leptin levels were assessed. Forty minutes after breakfast, the EG performed CT which included an indoor cycling class (40min, OMNI 5-7) followed by resistance training (3 series performed until exhaustion in the supported row machine, leg press, straight bench press, knee extensor, elbow flexor, knee flexor and elbow extensor, 85% 1RM, 2-3min interval). The CG did not perform the physical exercises. At the end of the CT, blood samples were collected from the EG. Descriptive statistics were used and for the inferential analysis a two-way ANOVA was undertaken. The Shapiro-Wilk test was used to check homogeneity and Tukey's Post-Hoc test was used for normality analysis. The significance level adopted was p<0.05. Results: The EG (Δ% = 2.92; p = 0.01; 15.05±3.32ng/mL for 12.13±3.01ng/mL) and CG (Δ% = 5.32; p = 0.00; 26.04±9.13ng/mL for 20.72±8.51ng/mL) had significant reductions in plasma leptin levels.
Conclusion: In its acute phase, CT causes a reduction in the plasma leptin levels of overweight individuals.