Participants
Twenty two participants took part in the study, and they have ages mean 29.27 standard deviation (S.D.) 6.97 ranged 21-49 years old, heights mean 168.45 SD 10.14 ranged 155-191 cm, weights mean 71.69 SD 10.12 ranged 51-120 kg, body mass index (BMI) mean 25.01 SD 4.92 ranged 20.4-40.7, and 10 male and 12 female.
Variables given by Oxycon Mobile ® system
The results on the major parameters, e.g. VO2 are shown in Table 1, and each parameter is analysed and plotted, one by one, as below.
VO2 mean ml/min
The level of oxygen consumption (VO2 mean, ml/min) in the S1, S2, S3 showed strong correlation with T1, T2, T3, where S1 and T1 are baseline cadence in stepper and treadmill movements, S2 and T2 represents 20% higher cadence than the baseline one, and S3 and T3 20% lower cadence than the baseline one. Mean values showed that S3 consumed more energy than T3 by approximately 14% (Table 1). The correlation coefficient between stepper and treadmill movements in VO2 is very strong (0.789, p< 0.001) and a linear regression was constructed as seen in Figure 4.
Table 1. VO2 oxygen consumption and other parameters using stepper and treadmill
Measure
|
Mean
|
Std. Error
|
95% Confidence Interval
|
p
|
note
|
Lower Bound
|
Upper Bound
|
VO2 Mean ml/min
|
R
|
255.6
|
18.3
|
217.4
|
293.9
|
<0.001
|
vs all
|
S1
|
834.5
|
63.9
|
700.7
|
968.3
|
0.285
|
vs T1
|
S2
|
919.5
|
71.4
|
770.1
|
1068.9
|
0.478
|
vs T2
|
S3
|
772.2
|
63.7
|
638.8
|
905.6
|
<0.016
|
vs T3
|
T1
|
796.8
|
62.6
|
665.8
|
927.8
|
T2
|
959.6
|
73.7
|
805.3
|
1113.9
|
T3
|
677.7
|
58.4
|
555.6
|
799.9
|
EqO2 Mean
|
R
|
33.6
|
1.1
|
31.2
|
35.9
|
<0.001
|
vs all
|
S1
|
29
|
0.7
|
27.6
|
30.4
|
0.455
|
vs T1
|
S2
|
29
|
0.7
|
27.5
|
30.5
|
0.56
|
vs T2
|
S3
|
28.2
|
0.6
|
26.9
|
29.4
|
<0.001
|
vs T3
|
T1
|
28.3
|
0.8
|
26.6
|
30.1
|
T2
|
28.6
|
0.7
|
27.1
|
30.1
|
T3
|
29.9
|
0.5
|
28.8
|
31
|
VCO2 Mean ml/min
|
R
|
234
|
16.9
|
198.5
|
269.4
|
<0.001
|
vs all
|
S1
|
799.9
|
69.8
|
653.8
|
945.9
|
<0.008
|
vs T1
|
S2
|
859.8
|
71.8
|
709.6
|
1010.1
|
0.905
|
vs T2
|
S3
|
670.8
|
54.1
|
557.6
|
784
|
<0.031
|
vs T3
|
T1
|
690.8
|
52.6
|
580.7
|
800.9
|
T2
|
853
|
63.7
|
719.8
|
986.2
|
T3
|
598.8
|
55.3
|
483
|
714.7
|
VO2 Max ml/min/kg
|
R
|
4.44
|
0.3
|
3.81
|
5.07
|
p<0.001
|
vs all
|
S1
|
12.35
|
0.66
|
10.97
|
13.73
|
0.291
|
vs T1
|
S2
|
13.79
|
0.72
|
12.29
|
15.28
|
0.751
|
vs T2
|
S3
|
11.37
|
0.57
|
10.17
|
12.56
|
0.003
|
vs T3
|
T1
|
11.75
|
0.54
|
10.63
|
12.87
|
T2
|
14.03
|
0.78
|
12.39
|
15.66
|
T3
|
10.03
|
0.47
|
9.03
|
11.02
|
EqCO2 Mean
|
R
|
36.5
|
1.1
|
34.2
|
38.8
|
<0.001
|
vs all
|
S1
|
30.6
|
0.6
|
29.3
|
31.8
|
<0.022
|
vs T1
|
S2
|
31.3
|
0.7
|
29.7
|
32.8
|
0.3
|
vs T2
|
S3
|
32.5
|
0.7
|
30.9
|
34
|
<0.001
|
vs T3
|
T1
|
32.5
|
0.8
|
30.8
|
34.2
|
T2
|
32.1
|
0.8
|
30.3
|
33.9
|
T3
|
34.1
|
0.8
|
32.4
|
35.7
|
Note: R- rest, S1–stepper movement with a normal cadence, S2-stepper cadence 20% higher than normal one, S3- stepper cadence 20% lower than the normal, T1-treadmill walking with a normal cadence, T2-treadmill 20% higher, T3-treadmill 20% lower
Breathing equivalent for oxygen (EqO2)
EqO2 mean in S1 (28.992) was very close to T1 mean value (28.33). It was found that the difference between S3 and T3 was significant, and T3 was higher than S3 by approximately 6% (Table 1). The correlation coefficient was also strong (0.489, p <0.001) and linear regression as seen in Figure 5. The mean at Rest was observed at 33.560, which was significantly higher than the other situations, because EqO2 is reversely proportional to VO2.
Volume of CO2 expired
VCO2, which is the production of carbon dioxide per minute, was recorded. It is found that S1 and S3 were higher than T1 and T3 by approximately 16% and 11% respectively (Table 1). The correlation coefficient between two types of movements is 0.778 (p<0.001) as seen in Figure 6.
Respiratory exchange ratio (RER)
RER mean values showed a correlation between stepper and treadmill as in Figure 8, and S1 and S2 higher than T1 and T2 by approximately 8% and 6% respectively (Table 2). The correlation coefficient is 0.507 with p< 0.001, again confirming the correlation between the stepper and treadmill movements.
Table 2 Respiratory exchange ratio and parameters in stepper and treadmill measurements
Measure
|
Mean
|
Std. Error
|
95% Confidence Interval
|
p
|
note
|
Lower Bound
|
Upper Bound
|
Qtc Mean L/min
|
R
|
1.9
|
0.1
|
1.6
|
2.1
|
<0.001
|
vs all
|
S1
|
5.5
|
0.4
|
4.6
|
6.4
|
0.323
|
vs T1
|
S2
|
6.1
|
0.5
|
5.1
|
7.1
|
0.682
|
vs T2
|
S3
|
5
|
0.4
|
4.2
|
5.9
|
<0.033
|
vs T3
|
T1
|
5.3
|
0.4
|
4.4
|
6.1
|
T2
|
6.3
|
0.5
|
5.3
|
7.2
|
T3
|
4.5
|
0.4
|
3.8
|
5.3
|
MET Mean
|
R
|
1
|
0.1
|
0.9
|
1.1
|
<0.001
|
vs all
|
S1
|
3.2
|
0.2
|
2.8
|
3.6
|
0.221
|
vs T1
|
S2
|
3.5
|
0.2
|
3.2
|
3.9
|
0.513
|
vs T2
|
S3
|
3
|
0.2
|
2.7
|
3.3
|
<0.002
|
vs T3
|
T1
|
3
|
0.1
|
2.7
|
3.3
|
T2
|
3.7
|
0.2
|
3.2
|
4.2
|
T3
|
2.6
|
0.1
|
2.3
|
2.8
|
VE Mean L/min
|
R
|
9.6
|
0.7
|
8.2
|
11.1
|
<0.001
|
vs all
|
S1
|
26.2
|
2.2
|
21.5
|
30.8
|
<0.042
|
vs T1
|
S2
|
28.9
|
2.7
|
23.3
|
34.6
|
0.916
|
vs T2
|
S3
|
23.5
|
1.8
|
19.8
|
27.1
|
0.115
|
vs T3
|
T1
|
24
|
1.7
|
20.4
|
27.6
|
T2
|
29.1
|
2.2
|
24.5
|
33.7
|
T3
|
21.8
|
1.7
|
18.2
|
25.5
|
EE mean Kcal/min
|
R
|
1791.7
|
130.1
|
1519.4
|
2064.1
|
<0.001
|
vs all
|
S1
|
5979.2
|
472.1
|
4991.1
|
6967.3
|
0.129
|
vs T1
|
S2
|
6557.5
|
518.3
|
5472.7
|
7642.3
|
0.597
|
vs T2
|
S3
|
5420
|
447
|
4484.4
|
6355.7
|
<0.018
|
vs T3
|
T1
|
5592
|
437.4
|
4676.5
|
6507.5
|
T2
|
6774.3
|
519.1
|
5687.9
|
7860.7
|
T3
|
4769.2
|
418.6
|
3893.1
|
5645.3
|
RER Mean
|
R
|
0.92
|
0.018
|
0.882
|
0.959
|
<0.05
|
vs S3/T1
|
S1
|
0.95
|
0.017
|
0.915
|
0.985
|
<0.001
|
vs T1
|
S2
|
0.929
|
0.014
|
0.9
|
0.958
|
<0.009
|
vs T2
|
S3
|
0.871
|
0.011
|
0.848
|
0.893
|
0.332
|
vs T3
|
T1
|
0.873
|
0.015
|
0.84
|
0.905
|
T2
|
0.893
|
0.012
|
0.867
|
0.919
|
T3
|
0.881
|
0.013
|
0.854
|
0.908
|
Note: R- rest, S1–stepper movement with a normal cadence, S2-stepper cadence 20% higher than normal one, S3- stepper cadence 20% lower than the normal, T1-treadmill walking with a normal cadence, T2-treadmill 20% higher, T3-treadmill 20% lower
Energy consumption using stepper and treadmill (EE)
At Rest, the lowest mean of energy consumption (EE) was recorded as 1791.723. It was found that S3 was significantly higher than T3 by approximately 14% as shown in Table 2. The correlation coefficient was 0.790 with p<0.001 as in Figure 9, showing strong correlation between two types of movements.
Ventilation (VE)
VE mean value showed that S1 was higher than T1 by approximately 9% in Table 1. The correlation coefficient between stepper and treadmill is 0.826 with p<0.001 as Figure 10.
MET using stepper and treadmill
Mean value for MET showed that S3 is higher than T3 by approximately 15% in Table 2. The correlation coefficient for MET was 0.598 with p<0.001 as Figure 11, so two type of movements were correlated.
Qtc
Qtc results showed correlation between stepper and treadmill as well, with the coefficient as 0.806 with p<0.001 as in Figure 12. It is also found that S3 is higher than T3 by approximately 11% as in Table 2.