Enhanced Physical Activity Improves Selected Outcomes in Children With ADHD: Systematic Review.

This review examines associations between physical activity (PA) and cognitive, behavioral, and physiological outcomes in children with attention-deficit/hyperactivity disorder (ADHD). We reviewed studies on participants ≤18 years old, published in English between January 1998 and December 2014, in PubMed, CINAHL, PsycINFO, and Cochrane Reviews. Twenty-six studies were grouped into two categories: those that did and did not account for effects of ADHD medications. The first category showed lower levels of PA and improved cognitive and behavioral outcomes in youth whose ADHD was treated with medications. The second category showed a positive association between PA levels and cognitive and behavioral outcomes in youth whose ADHD was not treated with medications. For both categories of studies, results were inconclusive regarding physiological outcomes. Randomized controlled trials are needed to better clarify the relationship between PA and outcomes in youth with ADHD, and particularly to understand the impact of ADHD medications on that relationship.

Fat patterning of adolescents: Allometry of fatfolds.

The relationship between fatfold thickness and fat mass of 101 male and 66 female adolescents (10-16 yr) was examined with the allometric equation y = bxa . Body composition was assessed by underwater weighing and 5 fatfolds were measured: triceps, subscapular, suprailiac, abdominal, and thigh. Percent body fat ranged from 4.9% to 56.1%. The log of each fatfold thickness was plotted versus the log of fat mass. All the relationships were linear and exhibited monophasic allometry. All the alpha coefficients (slope of the log-log plots) exhibited positive allometry. The prepubescent male and female alphas were similar and had the same pattern. The pattern contrasted the trunk with the extremity fatfolds. No differences (P > .05) were found between the alphas for the pubescent males. The triceps alpha of the pubescent females was less (P < .05) than the subscapular, suprailiac, and abdominal alphas. The thigh, subscapular, suprailiac, and abdominal alphas were not significantly (P > .05) different. In conclusion, the trunk was the predominant site of subcutaneous fat deposition for prepubescents, while pubescents exhibit a more general pattern of fat distribution. © 1992 Wiley-Liss, Inc.

Basal metabolism of obese adolescents: Evidence for energy conservation compared to normal and lean adolescents.

To test if obese adolescents systematically conserve energy, comparisons of basal metabolic rate (BMR) of obese, normal, and lean male and female adolescents were made. Obese had eleevated values by as much as 23% (P ≤ 0.05) expressed as kJ · 24 hr-1 compared to the normal and lean. When indexed to body mass (kJ · kg-BM-1 · hr-1 ), the BMR for the obese was depressed by as much as -53% (P ≤ 0.01), and when indexed to fat free mass (kJ · kg-FFM-1 · hr-1 ) it was depressed by -33% compared to normal and lean adolescents. A "theoretical metabolic rate" (TMR), based on the observed fat free mass, fat mass, and their thermal equivalents, was proposed as a theoretical way to properly index basal metabolism, referenced to body composition. Comparisons of the TMR between the obese, normal, and lean revealed that the obese values were depressed by an average -22% (P ≤ 0.05). In comparison, differences in TMR between the normal and lean males and females were no larger than 8% (ns). It was concluded that since both the observed BMR (expressed relative to body composition), and the derived TMR values were depressed for the obese compared to the normal and lean adolescent, the data suggest an energy saving hypothesis for obese adolescents.

New approach for estimating excess body fat from changes in abdominal girth.

A new method is proposed for determining changes in percent body fat (%BF) based on the difference between an initial value for abdominal girth (AG) and a calculated "target" AG based on a desired %BF. Group data from large-scale anthropometric surveys in the military were used to derive specific reference values for Q, defined as the ratio of AG at a desired %BF to F(√BMkg /Htm ). For an individual, Q*F resulted in an AG that corresponded to a desired %BF (set at approximately 20% for males and 30% for females). The method was applied to professional football players, longshoremen, shot-put and weight-lifting athletes, and obese males and females who reduced body mass and altered their body composition. The results showed that changes in AG with body mass loss were proportional to percentage changes in total body fat loss. These relationships permitted extrapolation to a projected target AG that corresponded to a desired %BF. The proposed method differs from the traditional approach that first determines %BF, and then the individual attempts to achieve a desired change in body mass or body composition. The objective of the new method is straightforward; the individual endeavors to attain a target AG that corresponds to a desired %BF.

Individual Differences in Relative Endurance and Physiological Response for Prepubescents, Adolescents, and Adults.

The extent of individual differences in relative endurance and physiological response was examined in adolescent boys (n=22) and compared to data of prepubescent boys (n = 21) and adult men (n = 21). Subjects performed two (test and retest) relative endurance cycle ergometer tests at an initial rate of 105% V̇O2 max, which they attempted to maintain for 8 minutes. Relative endurance performance was defined as the revolutions for each minute of the test (RPM). There were no differences among groups for the total revolutions turned or the total percent dropoff from the initial rate. All groups had similar patterns for consistency of RPM except for Minute 3. The prepubescent boys exhibited the greatest within-individual variation (Si) for HR, especially after Minute 4 (p<.05). On the average, a greater proportion of the total variability in HR was due to Si in comparison to true individual differences (St) for the prepubescents (47%) than either the adolescents (13%) or the adults (11%). The adolescents had the lowest proportion of total variability in V̇O2 due to Si (adolescents 9%, adults 16%, prepubescents 26%). The data support an earlier hypothesis of a threshold age effect on the stability of individual differences for physiological response during relative endurance exercise. A change may occur during adolescence.

Validity of anthropometric regression equations for predicting changes in body fat of obese females.

The validity of ten popular anthropometric percent fat prediction equations for estimating changes in percentage of body fat for obese females was studied. Thirty-one obese females (mean ± SEM, %fat = 36.7 ± 1.1%, body mass = 75.6 ± 1.7 kg, age = 32.8 ± 1.1 years) participated in a diet-only, diet-plus-exercise, or exercise-only program. Subjects lost 2.7 ± 0.3 fat percentage points and 3.0 ± 0.3 kg body mass during the 8-week study. While many of the equations had acceptable validity before and after body mass loss, when applied to the prediction of changes in body fat none of the equations was acceptable. It was concluded that use of anthropometric prediction equations to estimate individual percent fat change scores results in large errors and is not recommended.

The Underweight Female.

Thin is in-but are underweight women healthy? These researchers categorize three types, ranging from sedentary malnourished women to lean athletes who often have menstrual irregularities.