2.1. Participants
The study included 64 men (51.34 ± 8.02 years), after myocardial infarction, who underwent percutaneous coronary angioplasty. The tests were performed during the second stage of rehabilitation. All participants of the experiment were qualified for model A (exercise test result ≥ 7 MET or 100 W). Reducing the number of confounding factors, such as age, sex, disease entity, treatment method, and level of exercise tolerance, patients included in the study were randomized to two rehabilitation procedures:
The characteristics of the subjects are presented in Tables 1–4.
Inclusion criteria: consent to participate in the study, documented stable ischemic heart disease or an uncomplicated course of myocardial infarction, time from the last cardiovascular event < 2 months, stress test result ≥ 7 MET/100 W, left ventricular ejection fraction (LVEF) ≥ 50%. Exclusion criteria: refusal to participate in the study, recent myocardial infarction, LVEF < 50%, coronary artery bypass surgery, unregulated hypertension, unstable coronary artery disease, arrhythmias and conduction disturbances, established cancer, diseases of the central or peripheral nervous system, varicose veins of the lower limbs, osteoarthritis of the peripheral joints and the spine, unhealed injuries of the lower limbs, advanced peripheral arteriosclerosis, age ≥ 75 and incomplete medical documentation
Table 1
Characteristics of both groups
Variable
|
Group IC
(N = 32)
|
Group ST
(N = 32)
|
Age [years]
|
53.40 ± 4.31
(38–74)
|
55.31 ± 6.45
(41–72)
|
Height [cm]
|
177 ± 4.66
(169–189)
|
178.20 ± 7.55
(163–188)
|
Weight [kg]
|
85.65 ± 7.55
(72–101)
|
86.09 ± 13.22
(66.90-111.24)
|
BMI [kg/m2]
|
26.48 ± 1.61
(22.28–33.42)
|
27.82 ± 6.63
(22.80-31.23)
|
LVEF [%]
|
55.22 ± 5.95
(51–59)
|
54.50 ± 8.44
(52–58)
|
BMI –body mass index, N – number, LVEF – left ventricular ejection fraction |
Table 2
Disease entities occurring in patients of both groups
Type
|
Group IC
N(%)
|
Group ST
N(%)
|
Ischemic heart disease
|
27(84.3%)
|
28(87.5%)
|
Type 2 diabetes
|
6(18.75%)
|
8(25%)
|
Hyperlipidemia
|
9(28.12%)
|
11(34.37%)
|
Hypertension
|
14(43.75%)
|
18(56.25%)
|
Myocardial infarction
|
32(100%)
|
32(100%)
|
Ischemic disease and myocardial infarction were dominant in both groups
Table 3
Type of myocardial infarction
Type
|
Group IC
N(%)
|
Group ST
N(%)
|
NSTEMI
|
26(81.25%)
|
28(87.5%)
|
STEMI
|
6(18.75%)
|
4(12.5%)
|
Total
|
32(100%)
|
32(100%)
|
NSTEMI – non-ST elevation myocardial infarction, STEMI – ST elevation myocardial infarction |
Table 4
Number of implanted stents
Number
|
Group IC
N(%)
|
Group ST
N(%)
|
1
|
27(84.37%)
|
28(87.5%)
|
2
|
4(12.51%)
|
4(12.5%)
|
≥ 3
|
1(3.12%)
|
0(0%)
|
Implantation of 1 stent was predominant in all groups.
2.2. Experimental Procedure
Both the standard group and the IC group were subjected to a 24-day improvement program, which included 22 training units (2 days for initial and final tests) performed 5 times a week following ESC standards (a detailed training program is presented in Table 5. Throughout the entire research procedure, the patients were supervised by medical personnel consisting of a physiotherapist and a cardiologist.
Table 5
Training following ESC recommendations
Type of training
|
Methodology
|
Workload
|
Endurance training
|
Training on a bicycle ergometer,
5 times a week
30 minutes
|
Workload applied on the basis of calculation of heart rate training, starting from 60% of heart rate reserve increased by 10% after
5 units of training,
to 80 % of heart rate reserve,
14 degrees of subjective scale
effort assessment by the Borg scale
|
Resistance training
|
Exercises in the form of
training station,
5 times a week
30 minutes
|
General exercises
|
Exercises in the gym –
elements of aerobic and anaerobic training, stretching, breathing exercises,
5 times a week
30 minutes
|
The intensity of the exercise varied on the basis of the calculated training heart rate, starting from 60% of the heart rate reserve, increasing by 10% after 5 training units, up to 80% of the heart rate reserve, up to a maximum of 15 according to the Borg scale.
Endurance training on a bicycle ergometer (Kettler Ergometer X1) began with a 3-minute ride without load (0 W), followed by 5 cycles – a 3-minute load phase and a 2-minute rest phase, a total of 25 minutes of riding. The training session ended with 2 minutes of cycling without load. The training on a bicycle ergometer lasted a total of 30 minutes. After each training unit, stretching of the muscle groups involved during the ride was performed (5 minutes). People from the IC group performed indoor cycling training (Tomahawk I.C.E. Indoor Cycling) instead of the traditional interval training. The training ride lasted 30 minutes in total and started with a 5-minute warm-up with no load, in the rhythm of 100–110 RPM. The main part included cycling to the rhythm of changing music, including sitting and standing positions, and lasted 22.5 minutes (60–110 RPM). The main part was followed by a 2.5-minute cool down with a gradually decreasing load. The cycling cadence (RPM) was determined by the rhythm beats (BPM) present in each piece, being an important motivating instrument; moreover, the cadence of the rotation was signaled by the instructor. The unit ended with 5 minutes of stretching of the muscle groups – the muscles of the chest, back, quadriceps and biceps muscles of the thigh, as well as the buttocks, forearms and arms. The stretching was performed on mats placed on the dance floor. Details of the training protocol are presented in Table 6. Patients from the experimental group also participated in the other two forms of training (resistance and general improvement), as did the control group (Table 5).
Table 6
Protocol of the indoor cycling training unit
Part of the training session
|
Time (min)
|
Borg scale
|
RPM
|
Position/ technique
|
Warm-up
|
1–5
|
9–10
|
100–110
|
Position 2 (2½min)
Position 1 – SF (2½min)
|
Appropriate training
|
5–10
10-17.5
17.5–22.5
22.5–27.5
|
12–13
12–14
13–14
11–12
|
110
110
80
80
100–110
100
60–80
100
60–80
100
80
80
60–80
100–110
|
Position ja 1 (2 min)
Position a 2 (2 min)
Position a 2 – SC (1min)
Position a 3 – StC (½min)
Position a 1 (2½min)
Position a 2 (2½min)
Position a 3 StC (½min)
Position 1 (1½min)
Position ja 2 – SC (1min)
Position 2 (3½min)
Position 3 – StC (½min)
Position 2 (2min)
Position a 2 – SC (2min)
Position a 2 (1min)
|
Cool down
|
27.5–30
|
9–10
|
100
|
Position a 1 – SF
|
Stretching
|
30–35
|
9
|
-
|
-
|
min – minute, position1 – close, position 2 – open, position 3 – standing, |
RPM – revolutions per minute, SC – seated climb, SF – seated flat, StC – standing climb, StF – standing flat |
The following was carried out before commencing the training program and immediately after its completion:
- Electrocardiographic exercise test on a treadmill (six-stage Bruce protocol: stage 1 = 2.7 km/h, 10%, stage 2 = 4.0 km/h, 12%, stage 3 = 5.5 km/h, 14%, stage 4 = 6.8 km/h, 16%, stage 5 = 8.0 km/h, 18%, stage 6 = 8.8 km/h, 20%) Exercise test using the Excalibur Sport cycle ergometer (Lode, Groningen, The Netherlands) [18]. The following were measured: test duration (min), distance covered (m), energy cost (MET), heart rate at rest and maximum (BPM), systemic blood pressure at rest and maximum (mmHg), criteria for ending the test (physiological: submaximum heart rate, i.e., 85% of HRmax determined on the basis of the following formula: 208-0.7x age or fatigue; pathological: stenocardial pain, ST segment, and T-wave changes, rhythm and/or conduction disorders, blood pressure increase above 250/120 mmHg), maximum oxygen uptake (VO2max).
- Two-dimensional ultrasound heart test, measured hemodynamic parameters (GE Vivid Q): left ventricular end-diastolic dimension (LVEDD; mm), left ventricular end-systolic dimension (LVESD; mm), left ventricular end-systolic volume (LVESV; mL) as per the following formula:
LVESV = 7/(2.4 + LVESD) - (LVESD), left ventricular end-diastolic volume (LVEDV; mL) as per the following formula: LVEDV = 7/(2.4 + LVEDD) - (LVEDD), left ventricular ejection fraction (LVEF; %), left ventricular mass (LVM; g), left ventricular mass index (LVMI; g/m2) based on the Devereux formula: LVMI = LVM/BSA (left ventricular mass/body surface area)
- Blood lipid profile test. Measured parameters: Total cholesterol – TC (mg/dL), high-density lipoproteins - HDL (mg/dL), low-density lipoproteins – LDL (mg/dL), triglycerides – TG (mg/dL)
Before, during and immediately after each training session, heart rate (Polar, FT1) and blood pressure (SOHO, 110 HS-50A) measurements were made, as well as the degree of perception of effort according to the 20-point Borg scale. The intensity of the exercise varied on the basis of the calculated training heart rate, starting from 60% of the heart rate reserve, increasing by 10% after 5 training units, up to 80% of the heart rate reserve, up to a maximum of 15 according to the Borg scale.
The following was carried out before commencing the training program and immediately after its completion:
- Electrocardiographic exercise test on a treadmill (six-stage Bruce protocol: stage 1 = 2.7 km/h, 10%, stage 2 = 4.0 km/h, 12%, stage 3 = 5.5 km/h, 14%, stage 4 = 6.8 km/h, 16%, stage 5 = 8.0 km/h, 18%, stage 6 = 8.8 km/h, 20%) Exercise test using the Excalibur Sport cycle ergometer (Lode, Groningen, The Netherlands)[18]. The following were measured: test duration (min), distance covered (m), energy cost (MET), heart rate at rest and maximum (BPM), systemic blood pressure at rest and maximum (mmHg), criteria for ending the test (physiological: submaximum heart rate, i.e., 85% of HRmax determined on the basis of the following formula 208-0.7x age or fatigue; pathological: stenocardial pain, ST segment, and T-wave changes, rhythm and/or conduction disorders, blood pressure increase above 250/120 mmHg), VO2max.
- Two-dimensional ultrasound heart test, measured hemodynamic parameters (GE Vivid Q): LVEDD (mm), LVESD (mm), LVESV (mL) as per the following formula:
LVESV = 7/(2.4 + LVESD) - (LVESD), LVEDV (mL) as per the following formula: LVEDV = 7/(2.4 + LVEDD) - (LVEDD), LVEF (%), left ventricular mass (LVM; g), left ventricular mass index (LVMI; g/m2) based on the Devereux formula: LVMI = LVM/BSA (left ventricular mass/body surface area)
- Blood lipid test profile. Measured parameters:
total cholesterol – TC (mg/dL), high-density lipoproteins – HDL (mg/dL), low-density lipoproteins – LDL (mg/dL), triglycerides – TG (mg/dL) [18]
2.3. Data Analysis