Physical inactivity correlates strongly with socio-demographic factors such as age, gender and educational level. Results identify social and economic groups to which future public health interventions should be aimed to increase PA in the Chilean population.

Ross, R, ALDuhishy, A, and González-Haro, C. Validation of the cosmed K4b2 portable metabolic system during running outdoors. J Strength Cond Res 34(1): 124–133, 2020—The aim of this study was to determine the agreement of the K4b2 metabolic system in comparison with the Douglas bags (DB) method for determining gas-exchange variables during both indoor treadmill and outdoor running. Nineteen endurance-trained males undertook 3 maximal incremental running tests, separated by at least 2 days: K4b2 indoor test (K1), K4b2 outdoor test (K2), and DB indoor test. Gas-exchange parameters (Vo 2, Vco 2, VE, VI, Respiratory Exchange Ratio, FEO2, and FECO2) and heart rate were measured during K1, K2, and DB tests. For most of the variables (Vo 2, %Vo 2, %Vco 2, VE, and VI), the agreement was better for K2 when compared with DB than for K1 when compared with DB. For Vco 2, FEO2, and FECO2, the agreement was better between K1 when compared with DB than for K2 when compared with DB. Respiratory Exchange Ratio showed a similar agreement between both conditions (K1 vs. DB and K2 vs. DB). K4b2 seems valid for measuring gas-exchange variables during submaximal and maximal running velocities in an outdoor environment. Although K2 mean systematic error (bias) was low, the aleatory error was moderate. These considerations should be taken into account when using K4b2 to measure gas-exchange parameters both during indoor and outdoor activities.

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(1) Background: Obesity is one of the most prevalent health problems worldwide. Studies have evidenced that the increase in body weight affects the normal neuromusculoskeletal function, which leads to abnormal gait patterns and impaired balance. (2) Objective: The aim of this study was to examine the influence of dual-task activity (cognitive-motor task) on gait parameters and balance among obese students. (3) Material and methods: A cross-sectional study was conducted among students (18–28 years old), including 120 obese and 120 age-matched normal-weight control subjects, selected at random using simple random sampling, from the Majmaah, Riyadh, Dammam, and Jizan regions of Saudi Arabia. The gait speed was measured in seconds while the controls and the obese subjects performed a dual-task activity of walking down a level, well-lit, narrow lane at their own speed, counting backwards from 100 by 4 s. (4) Results: The results of our study suggest a significant difference in the effect of the dual-task paradigm on the gait speed (t = 21.05, p = 000) of obese participants when compared to their age-matched counterparts. A significant correlation was found between BMI and gait speed and balance, irrespective of the gender of the obese student. A high degree of positive correlation (r = 0.705, p < 0.001) was found between BMI and gait speed, and a high degree of inverse correlation (r = −0.648, p < 0.001) was found between BMI and balance among obese students A multiple regression model explained 60% of the variance in gait speed and was statistically significant (R2 = 0.60, F (4, 235) = 90.65, p = 0.000) with BMI (β = 0.018, p = 0.000) and balance (β = 0.015, p = 0.000) significantly predicting gait speed. (5) Conclusion: The results of the current study provide evidence that obesity significantly influences gait speed and balance due to the inclusion of a contemporaneous cognitive task. The results also suggest that the dual-task paradigm affects both genders equally.

Objectives: To determine the applicability of Jones, Hansen, and Wasserman predictive equations for maximal oxygen consumption (VO 2max ) in Saudi females. Methods: This cross-sectional study was conducted at Imam Abdulrahman Bin Faisal University, Dammam, Kingdom of Saudi Arabia, between March and May 2017. Maximal oxygen consumption was measured directly through the COSMED system for cardiopulmonary exercise testing in 102 girls with normal body mass index (19-25 years old). Maximal oxygen consumption was indirectly predicted by Jones, Hansen, and Wasserman equations. Paired t-test, Pearson correlation, and Bland-Altman plot were used for comparison, correlation, and agreement analysis. Results: The difference between the mean and standard deviation (±SD) VO 2max values of the direct measurement (27.39±4.06 ml/kg −1 /min −1 ), and the Jones (35.19±2.12 ml/kg −1 /min −1 ), Hansen (33.64±0.24 ml/kg −1 /min −1 ), and Wasserman (35.20±0.17 ml/kg −1 /min −1 ) equations, was statistically significant ( p <0.001). Bland-Altman plot analysis suggested a lack of agreement between direct and predicted VO 2max . Pearson correlation failed to reveal any correlation between direct VO 2max and VO 2max calculated with any of the 3 equations. Conclusion: Jones, Hansen, and Wasserman equations for prediction of VO 2max cannot be justified in the studied population. For the better prediction of VO 2max , either these equations should be modified, or a new equation should be developed for the Saudi population.