*3.3. Energy Expenditure in Relation to Gender, Age Category, BMI Classification*

Significant gender differences in MET-min/week were found (*p* < 0.001), with male participants expressing higher values of energy expenditure in the pre-confinement condition compared to the female participants (Figure 2a). On the other hand, no significant gender differences were found during the confinement condition in MET-min/week (*p* = 0.53) (Figure 2b). The difference between pre- and during confinement showed a higher decrease in MET-min/week among male participants (Figure 2c).

**Figure 2.** Gender differences in MET-min/week (pre and during COVID-19). (**a**) Total weekly energy expenditure (MET-min/week) pre home confinement condition in relation to gender category. (**b**) Total weekly energy expenditure (MET-min/week) during home confinement condition in relation to gender category. (**c**) Total weekly energy expenditure (MET-min/week) difference between pre and during home confinement in relation to gender category. Legend: \*\*\*\*: (*p* < 0.001); ns: non-significant difference.

Analysis of the age categories showed a significant difference in MET-min/week between pre and during home confinement condition (*p* < 0.001), except for senior adults, where the difference was (*p* = 0.006). Pairwise comparison analysis revealed a significant difference between the young and adults (*p* < 0.001), young and senior adults (*p* < 0.001), young adults and adults (*p* < 0.001), and young adults and senior adults (*p* = 0.002) in MET-min/week pre confinement condition (Figure 3a). Likewise, the during-confinement condition pairwise analysis showed the same significant differences between the young and adults (*p* < 0.001), young and senior adults (*p* = 0.005), young adults and adults (*p* = 0.001), and young adults and senior adults (*p* = 0.02) in MET-min/week for the duringconfinement condition (Figure 3b). As depicted in Figure 3c, the highest MET-min/week difference between pre- and during confinement was found among the young and young adult categories.

**Figure 3.** Age category differences in MET-min/week (pre and during COVID-19). (**a**) Total weekly energy expenditure (MET-min/week) pre-home confinement condition in relation to age categories. Legend: Y: young; Y. A.: young adult; A: adult; S. A: senior adult; \*\*\*\*: (*p* < 0.001); ##: (*p* < 0.001); #: (*p* = 0.002); ¥¥: differences between pre and during confinement (*p* < 0.001); ¥: differences between pre- and during confinement (*p* = 0.006). (**b**) Total weekly energy expenditure (METmin/week) during home confinement condition in relation to age categories. Legend: Y: young; Y. A.: young adult; A: adult; S. A.: senior adult; \*\*\*\*: (*p* < 0.001); \*\*: (*p* = 0.005); ##: (*p* = 0.001); #: (*p* = 0.02). (**c**) Total weekly energy expenditure (MET-min/week) difference between the pre- and during-confinement condition in relation to age categories. Legend: Y: young; Y. A.: young adult; A: adult; S. A.: senior adult.

Analysis regarding the differences between BMI categories revealed that during the pre-confinement condition the NW category showed a higher MET-min/week value compared to the UW (*p* = 0.006) and OW (*p* < 0.001) categories (Figure 4a). Likewise, in the during-confinement condition, the NW category showed a higher MET-min/week value compared to both UW and OW (*p* = 0.04) and (*p* < 0.001), respectively. On the other hand, when comparing MET-min/week between pre- and during-confinement conditions, statistically significant differences were found for all BMI categories (*p* < 0.001). Moreover, the analysis of MET-min/week differences between the pre- and during-confinement condition revealed that the NW was the category with the highest difference (Figure 4b).

**Figure 4.** BMI category differences in MET-min/week (pre and during COVID-19). (**a**) Total weekly energy expenditure (MET-min/week) pre and during home confinement condition in relation to BMI category. (**b**) Total weekly energy expenditure (MET-min/week) difference between pre and during home confinement in relation to BMI category. Legend: UW—underweight; NW—normal weight; OW—overweight; \*—(*p* < 0.05); \*\*\*\*—(*p* < 0.001); #—(*p* < 0.001).
