Table 1.
Characteristics of the 19 subjects (16 male; 3 female).
Fig 1.
The Cortex Metamax 3B automated gas analysis system.
Fig 2.
The 20 body joints of the human skeletal model.
Fig 3.
Temporal alignment of the hip centre joints of the participants for the squatting activity.
Fig 4.
The average oxygen consumption of the four fundamental movements.
Table 2.
Steady-State Energy Expenditure over 1-minute period.
Table 3.
The mean mechanical work with posture cost for the four fundamental movements over 1-minute period.
Fig 5.
Scatter plots showing relationships among the total mechanical works of upper body, lower body, and centre of mass.
Fig 6.
The RMSE and mean percentage errors of the predicted energy costs from KNNR for different values of k.
Fig 7.
The predicted energies from the three algorithms versus the actual energies for the 3 feature types 1D, 6D, and 7D.
The blue diagonal line denotes the 45° line. The two diagonal blue dashed lines denote the ±10% error about the 45° line.
Fig 8.
The Bland-Altman plots for 3 features types.
The differences between observed and predicted values from the three algorithms versus the actual observed energies for the 3 feature types 1D, 6D, and 7D. The solid line is the mean of the differences for the 3 features types, while the dotted lines denote ±2 standard deviations from the mean.
Table 4.
The RMSE (in kJ), mean percentage errors, and concordance correlation coefficients (CCC) of the GPR, KNNR, and LINR algorithms for the three feature types.
The figures in bold denote the smallest RMSE, percentage errors, or the largest concordance correlation coefficients.
Table 5.
The paired t-test results on the three algorithms with the Null hypothesis ℋ0: the predicted energy values from the two algorithms being considered come from the same distribution.
Fig 9.
The predicted energies from GPR versus the actual energies for the individual fundamental movements.
The vertical error bars denote one standard deviation on either side of the mean. The results were obtained by using the LOOCV technique on all the movements together.
Table 6.
The RMSE (in kJ) for the four activities standing jump (SJ), arm swing (AS), squat (SQ) and jumping jack (JJ).