The present study examined the relationship between maximal oxygen uptake (V̇O2max) and daily physical activity in a group of 7- to 12-year-old boys. V̇O2max was assessed through the incremental treadmill test using an open circuit system. Physical activity level was obtained from heart rate telemetry outside of school time for 8 hrs during weekdays and during 40 min of physical education classes. The findings indicated that the absolute value of V̇O2max increased with age, while relative to body weight it remained almost the same across age, with a mean of 48.4 ml · kg−1 · min−1. Moreover, heart rate telemetry showed that the boys spent a limited amount of time on activities that raise the heart rate to a level above 160 bpm (an average of 1.9%). In addition, V̇O2max was found to be significantly related to the percentage of time spent at activity levels at or above a heart rate of 140 bpm, but not with activity levels at or above a heart rate of 160 bpm.
Hazzaa M. Al-Hazzaa and Mohammed A. Sulaiman
Hazzaa M. Al-Hazzaa, Mohammad A. Alahmadi, Hana I. Al-Sobayel, Nada A. Abahussain, Dina M. Qahwaji and Abdulrahman O. Musaiger
Few studies have reported comprehensive and valid physical activity (PA) data for Saudi youth. Therefore, the purpose of this study was to examine patterns and determinants of PA among Saudi adolescents.
A cross-sectional study was conducted in Saudi secondary schools (15–19 years) during 2009/2010 and used multistage stratified cluster sample (N = 2866, 51.7% females). Weight, height, sedentary behaviors, PA, and dietary habits were assessed.
Roughly 44% of males and 20% of females were active (≥ 1 hour/day). Males in public schools were more active than in private schools, whereas the opposite was true for females. Females exercise mostly at home, whereas males exercise at public places. The majority of females exercise alone or with relatives, whereas males largely exercise with friends. Males were active for health and recreation whereas females were active for weight loss and recreation. Lack of time was the primary reason for inactivity in both sexes. The predictors of total PA time were gender, intakes of fruit, milk, energy drinks and vegetables and waist/height ratio (R 2 = 0.145).
The high inactivity levels, especially among females, are of great concern. Promotion of active living among youth should be a national public health priority.
Hazzaa M. Al-Hazzaa, Saeed A. Al-Refaee, Muhammed A. Sulaiman, Ma’ed Y. Dafterdar, Abdullah S. Al-Herbish and Andrew C. Chukwuemeka
The purpose of this study was to examine the maximal cardiorespiratory responses of trained adolescent male swimmers (SWM, N = 18), soccer players (SOC, N = 18), and moderately active reference subjects (CON, N = 16) to treadmill running (TRD) and arm ergometry (ARM). Mean values (±SD)for skeletal age were similar among the three groups (12.5± 1.9, 12.7 ± 1.1, and 12.5 ± 1.6 years, for the SWM, SOC, and CON, respectively). Allometric scaling procedures, relating VO2max and body mass, were used and mass exponents of .80 and .74 were identified for TRD and ARM data, respectively. During TRD testing SOC attained significantly higher VO2max values when expressed in ml · kg−1 · min−1, or ml · kg−0.80 · min−1 than the other two groups. However, during ARM testing, the SWM achieved significantly higher VO2peak values (ml · kg−0.74 · min−1 and scaled to arm-CSA) than SOC. The ratio of ARM-VAT to TRD-VAT was significantly higher in SWM (50.1± 9%) compared to SOC (41.2±5%), or CON (41.9 ± 6%).