Biomechanics and Medicine in Swimming XI

Swimming, Cycling, Running and Cardiovascular
Health
Bagheri, A.B. 1 , Mohebbi, h.d. 2 , Azizi, M.h. 3 , saiiari, A.r. 3
1 Islamic Azad University-Dezful Branch, Dezful, Iran
2 University of Guilan, Rasht, Iran
3 Islamic Azad University-Abadan Branch, Abadan, Iran
A number of epidemiological studies have proved the benefits of regular
physical activity for the prevention of CHD. Exercise recommendations
for health can be obtained from extrapolation between different modes
of exercise. Forty non-athlete male youth participated in this study for
the comparative effects of swimming, cycling and running on lipid and
lipoproteins serum. In this study, after aerobic training, HDL-c increased
and LDL-c decreased; so TC and TG decreased. The findings
suggest that moderate training performed over many weeks induces
positive changes in the plasma lipid and lipoproteins concentration in
youth. However, there were differences between the three groups. Swimming,
running and cycling are positive for health, although this study
suggested that they have different effects.
Key words: swimming, cycling, running, aerobic training, tc, tG,
ldl-c, hdl-c
IntroductIon
Cardiovascular diseases (CVD) are also reported to be the leading cause
of death in the eastern Mediterranean region including Iran. Epidemiological
studies have shown that a sedentary life and obesity are related
to coronary heart disease (CHD) (Andersen et al., 1995). In numerous
studies, inverse associations have been demonstrated between physical
activity, obesity and CHD (Daniel J. G, 2008. Kline et al., 1987. King
et al., 1995). A number of epidemiological studies have proved the benefits
of regular physical activity for the prevention of CHD. Despite the
fact that exercise is crucial in weight management, the obese are found
to have reduced exercise tolerance compared with the non-obese and are,
in fact, less active. Fat is the major source of energy during low-intensity
exercise, and as the intensity increases, the proportional contribution of
fat decreases. Nonetheless, at 75-80% of VO 2 max, total fat oxidation is
markedly above the resting value because the proportional contribution
of fat oxidation is not great, the total rate of energy expenditure is high.
Plasma fatty acids are the major source of energy during mild to moderate
energy expenditure. Exercise recommendations for health can be
obtained from extrapolation between different modes of exercise.
Methods
Subjects: Forty non-athletic men (Age 22.56 ± 2.77 yr) with overweight
(BMI >25 kg·m -2 ) participated in this study. Subjects were made fully
aware of the risks, benefits and stresses of the study and were given both
verbal and written instructions outlining the experimental procedure,
and their informed consent was obtained before screening. The personal
and medical information of the participants was obtained, as well as
previous exercise history by questionnaire. A pre-participatory exercise
screening questionnaire [Physical Activity Readiness questionnaire
(PARQ)] was administered (Chisholm et al., 1975). All participants
were asymptomatic and were not taking any form of medication known
to affect the lipoprotein profile. Before the training program (baseline),
according to the National Cholesterol Education Program (NCEP; 26)
classification of risk, no participants had ‘’borderline’’ or ‘’ undesirable’’
concentrations of either TC and LDL-C. These youth were all classified
as having ‘’desirable’’ concentrations of TC and LDL-c at baseline.
Subjects were divided into four groups randomly; that included ten per-
chaPter6.medicineandwatersafety
sons each. Three groups were assigned training regimens (swimming,
running, and cycling), and completed the exercise training program. Ten
subjects served as controls.
Measurements: Body weight (BW) was measured through calibrated
clinical scale and height was measured through stadiometer while the
participants wearing light clothing with no shoes. Body Mass Index
(BMI) was calculated as weight in kilograms divided by height in meters
squared (kg·m -2 ). Five ml of venous blood sample were collected after a
12-14 hours fast into vacationer tubes without anticoagulant in pre-test
and post test. Blood was allowed to clot at room temperature for 30
min before being centrifuged. Serum and red blood cells were separated
by centrifuge at 1500gr for 20 min. serum was transferred and stored
at-80º for analysis of lipids and lipoproteins. Total cholesterol (TC)
measured by the CHOD-PAP method. TG by the GPO-PAP method,
high density cholesterol (HDL) was determined after separation with
phosphotungstic acid and magnesium chloride, all using established kit
methods from Boehringer (Mannnheim, Germany). Low density lipoproteins
(LDL) was then estimated by using the Friedeweald equation
(Friedewald et al., 1972).
Swimming Training: Ten non-athlete male volunteers used swimming
training three times per week (t/wk) consecutively for 16 weeks.
Technique training (crawl) was provided to the subjects before starting.
The swimming training program consisted of submaximal crawl 30 min
pr day (min/d) (5 min activity and 2 min rest), 2d/wk with 50 – 60
percentage of each subject’s predicted maximal heart rate (max HR)
intensity in first and second month. Throughout the remainder of the
month, subjects trained at 30 min/d (5 min activity and 1 min rest), 2d/
wk, approximately 70 – 80 percentage of maxHR. During this study, the
subjects conducted to warm-up and cool-down (static stretching and
low intensity exercise).
Running Training: Ten non-athlete subjects performed running exercise
three t/wk during 16 weeks. They trained at 30 min/d (5 min
activity and 2 min rest), 2d/wk with 50 –60 percentage of each subject’s
max HR intensity in first and second week. Almost all subjects were
working at approximately 70 – 80 percentage of maxHR in throughout
the remainder of the weeks.
Cycling Training: Ten non-athlete male ended cycling (ergometer)
exercise three t/wk consecutively for 16 weeks. Subjects trained at 30
min/d (5 min activity and 2 min rest), 2d/wk with 50 –60 percentage
of each subject’s predicted max HR intensity in first and second week.
Almost all subjects were working at approximately 70 – 80 percentage
of maxHR in throughout the remainder of the weeks.
Statistical Analysis: Before hypothesis testing, data were assessed for
normality of distribution and homogeneity of variance. SPSS (V 15)
and Microsoft office Excel (V 2007) was utilized for statistical analysis
and graphic presentation. Main effects of training modality and time
(pre and post-exercise), were assessed using One-Way Analysis of Variance.
Statistical significance was conferred at P ≤ 0.05. Tukey test was
used for post hoc comparisons, when main effects were detected.
results
After 16 week of swimming, cycling and running exercise, there were
differences between experimental groups and control for TC (P ≤ 0.05)
(Figure 1) . (Control Group = 155.78 ± 35.3 vs. 157.35 ± 35.4, Swimming
Group (SG) = 155.76 ± 33 vs. 136.41 ± 35.9; Cycling Group
(CG) = 154.93 ± 36 vs. 140.03 ± 21.8; Running Group (RG) = 156.34 ±
34.7 vs. 139.25 ± 35.8). Total Cholesterol in three groups decreased; SG:
12.42%, CG: 9.61%, RG: 10.93%. Comparison with Tukey test showed
that no significant differences between Control Group and CG (p =
0.530) so RG (p= 0.317); but there were significant differences between
control group and SG (p = 0.012).
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