Body dimensions, exercise capacity and physical activity level of adolescent Nandi boys in western Kenya

The aim of this study was to characterize untrained Nandi boys (mean age 16.6 years) from a town (n = 11) and from a rural area (n = 19) in western Kenya (altitude approximately 2000 m.a.s.l.) in regard to their body dimensions, oxygen uptake and physical activity level. The town boys had a mean maximal oxygen uptake (VO(2 max)) of 50 (range: 45-60) mL kg(-1) min(-1), whereas the village boys reached a value of 55 (37-63) mL kg(-1) min(-1) ( p<0.01) in VO(2 max). The running economy, determined as the oxygen cost at a given running speed, was 221 mL kg(-1) km(-1) (597 mL kg(-0.75) km(-1)) for town as well as for village boys. The body mass index (BMI) was very low for town as well as for village boys (18.6 vs 18.4 kg m(-2)). The daily mean time spent working in the field during secondary school and doing sports were significantly higher in village boys compared to town boys (working in the field: 44.2 (0-128) vs 1.3 (0-11) min, p<0.01; sports: 32.0 (11-72) vs 12.8 (0-35) min, p<0.01, respectively). A positive correlation between the daily time spent doing sports and VO(2 max) was found when pooling the data from the town and the village boys (R = 0.55, p<0.01). It is concluded that the body dimensions of adolescent Nandi town and village boys corresponds well with findings in Kenyan elite runners. They are very slender with relatively long legs. In addition, the VO(2 max) of the village boys was higher than that of the town boys, which is probably due to a higher physical activity level of the village boys during secondary school.     

Free-living physical activity and energy expenditure of rural children and adolescents in the Nandi region of Kenya

Abstract

Purpose: To examine the relationship between physical activity and energy demands in children and adolescents with highly active lifestyles.

Methods: Physical activity patterns of 30 rural Kenyan children and adolescents (14?±?1 years, mean?±?SD) with median body mass index (BMI) z-score?=??1.06 [?3.29–0.67] median [range] were assessed by accelerometry over 1 week. Daily energy expenditure (DEE), activity-induced energy expenditure (AEE) and physical activity level (PAL) were simultaneously determined using doubly-labelled water (DLW). Active commuting to school was assessed by global positioning system.

Results: Mean DEE, AEE and PAL were 12.2?±?3.4, 5.7?±?3.0?MJ/day and 2.3?±?0.6, respectively. A model combining body mass, average accelerometer counts per minute and time in light activities predicted 45% of the variance in DEE (p?<?0.05) with a standard error of DEE estimate of 2.7?MJ/day. Furthermore, AEE accounted for ～47% of DEE. Distance to school was not related to variation in DEE, AEE or PAL and there was no association between active commuting and adiposity.

Conclusion: High physical activity levels were associated with much higher levels of energy expenditure than observed in Western societies. These results oppose the concept of physical activity being stable and constrained in humans.     

Decreased exercise capacity,strength, physical activity level and quality of life in adult patients with familial Mediterranean fever

Background Familial Mediterranean fever (FMF) is a systemic autoinflammatory disease that causes recurrent attacks of fever, polyserositis, arthritis or skin eruptions, resulting in pain in the abdomen, muscles, joints and chest. All of these might lead to a reduction in exercise capacity, muscle strength, physical activity level (PAL) and quality of life (QoL). Therefore, assesment of these parameters are important. The aim of this study was to assess exercise capacity, muscle strength, PAL, and QoL in patients with FMF as compared to controls.Materials and methodsA total of 40 subjects with FMF and 36 healthy control subjects participated in the study. The 6-minute walk test (6MWT) was used to assess exercise capacity. Muscle strength measurements for shoulder flexors, extensors and abductors, hip flexors, extensors and abductors, knee flexors and extensors, and ankle dorsiflexors were evaluated by hand-held dynamometer. PAL was assessed using the International Physical Activity Questionnaire-Short Form (IPAQ-SF). QoL was investigated by Nottingham Health Profile (NHP).Results Significant differences were found between patients and healthy subjects for 6MWT (p = 0.003), muscle strength of ankle dorsiflexors (p = 0.001), hip flexors (p = 0.047), extensors (p = 0.003) and abductors (p = 0.004), total scores of IPAQ-SF (p = 0.004), and pain (p < 0.001), physical mobility (p < 0.001) and energy level (p = 0.026) subscales of NHP. However, there were no significant differences between groups for the shoulder flexion (p = 0.089), extension (p = 0.440) and abduction (p = 0.232), hand grip strength (p = 0.160) , and knee flexion (p = 0.744) and extension (p = 0.155) muscle strength and emotional reaction (p = 0.088), sleep (p = 0.070) and social isolation (p = 0.086) subsets of NHP.ConclusionSubjects with FMF demonstrated lower exercise capacity, muscle strength, PAL and QoL than healthy peers. Therefore, it is important to evaluate and improve these parameters in patients with FMF.     

Habitual level of physical activity and cardiorespiratory endurance capacity in children

Summary A total of 257 healthy children (140 boys, 117 girls) varying in age from 5.7 to 18.5 years underwent graded exercise tests on a treadmill. Cardiorespiratory endurance capacity was assessed by determination of the ventilatory threshold, which was defined as the highest exercise intensity before a disproportionate increase occurred in pulmonary ventilation ( _E) relative to oxygen uptake ( ). The purpose of the present study was to investigate the relationship between the habitual level of physical activity (HLPA) and the cardiorespiratory endurance capacity in children. The HLPA was assessed by a standardized questionnaire. In boys and girls HLPA increased gradually with advancing age. For the group as a whole, the boys reached the highest values for HLPA. The most active boys reached the highest value for ventilatory threshold and the lowest value was found in the less active ones, except for the age span of 12–16 years. It is concluded that more active boys showed a higher cardiorespiratory endurance capacity, as assessed by the ventilatory threshold, compared to less active ones, except during puberty. It can be postulated that during puberty this effect may be overruled by the influence of other more dominant growth-related factors. In girls, because HLPA was rather low, there was no discriminative effect of HLPA on exercise performance, as would be expected.     

Gastrointestinal parasitic infection,anthropometrics, nutritional status,and physical work capacity in Colombian boys

This article tests the hypothesis that the presence of gastrointestinal parasites in Colombian boys is negatively associated with anthropometric characteristics, physical work capacity, blood hemoglobin (Hb) levels, and nutritional status. Anthropometric, Hb, V̇O₂ max, and parasite load data were collected on 1,016 boys in Cali, Colombia. The boys were classified as lower socioeconomic class (SEC) from either urban or rural environments, and upper SEC from an urban environment. Sixty-three percent of the boys were infected with gastrointestinal parasites and, of the infected boys, 80–95% had light parasite loads. Parasites found included Necator americanus, Ascaris lumbricoides, Entamoeba histolytica, Trichuris trichiura, Giardia spp., and Enterobius vermicularis. Infected boys had significantly lower weight, stature, weight-for-height (among 6–9-year-old boys), Hb levels, and V̇O₂ max (ANCOVA, controlling for age and SEC). In terms of nutritional status, infected boys were 1.47 times more likely to be classified as iron deficient than noninfected boys (chi-square, P < 0.001), and 1.61 times more likely to be classified as stunted (P < 0.001). Infection was not associated with wasting in any SEC group. In conclusion, light to moderate gastrointestinal parasite loads were associated with significantly lower weight, stature, weight-for-height (in 6–9-year-old boys), Hb levels, and V̇O₂ max, and a significantly higher frequency of IDA and stunting. These data suggest that comprehensive analyses of the nutritional status of populations in regions endemic for parasitic infection should include testing for the presence of infection. Am. J. Hum. Biol. 11:763–771, 1999. © 1999 Wiley-Liss, Inc.     

Frontal brain activity pattern predicts depression in adolescent boys

Limited research has explored the relationship between frontal brain activity and depression in adolescent boys. This study examined whether frontal brain activity predicted depressive symptoms in 41 adolescent boys one year later. A step-wise hierarchical regression analysis was conducted using frontal brain activity as predictors and depressive symptoms as the dependent variable, controlling for depressive symptoms at baseline. Results revealed that greater relative right-sided activity predicted depressive symptoms in adolescent boys one year later.     

Cardiorespiratory fitness and physical activity in Luo,Kamba, and Maasai of rural Kenya

Background:

Although habitual physical activity energy expenditure (PAEE) and cardio‐respiratory fitness (CRF) are now well‐established determinants of metabolic disease, there is scarcity of such data from Africa. The aim of this study was to describe objectively measured PAEE and CRF in different ethnic populations of rural Kenya.

Methods:

A cross‐sectional study was done among 1,099 rural Luo, Kamba, and Maasai of Kenya. Participants were 17–68 years old and 60.9% were women. Individual heart rate (HR) response to a submaximal steptest was used to assess CRF (estimated VO₂max). Habitual PAEE was measured with combined accelerometry and HR monitoring, with individual calibration of HR using information from the step test.

Results:

Men had higher PAEE than women (～78 vs. ～67 kJ day^?1 kg^?1, respectively). CRF was similar in all three populations (～38 and ～43 mlO₂·kg^?1 min^?1 in women and men, respectively), while habitual PAEE measures were generally highest in the Maasai and Kamba. About 59% of time was spent sedentary (<1.5 METs), with Maasai women spending significantly less (55%). Both CRF and PAEE were lower in older compared to younger rural Kenyans, a difference which was most pronounced for PAEE in Maasai (?6.0 and ?11.9 kJ day^?1 kg^?1 per 10‐year age difference in women and men, respectively) and for CRF in Maasai men (?4.4 mlO₂·min^?1 kg^?1 per 10 years). Adjustment for hemoglobin did not materially change these associations.

Conclusion:

Physical activity levels among rural Kenyan adults are high, with highest levels observed in the Maasai and Kamba. The Kamba may be most resilient to age‐related declines in physical activity. Am. J. Hum. Biol. 2012. © 2012 Wiley Periodicals, Inc.

     

Body dissatisfaction prospectively predicts depressive mood and low self-esteem in adolescent girls and boys.

This research examined whether body dissatisfaction prospectively predicted depressive mood and low self-esteem in adolescent girls and boys 5 years later. Participants were early-adolescent girls (n = 440, Time 1 M age = 12.7 years) and boys (n = 366, Time 1 M age = 12.8 years) and midadolescent girls (n = 946, Time 1 M age = 15.8 years) and boys (n = 764, Time 1 M age = 15.9 years). After controlling for Time 1 of the relevant dependent variable, ethnicity, socioeconomic status, and body mass index, Time 1 body dissatisfaction was a unique predictor of Time 2 depressive mood and low self-esteem in early-adolescent girls (depressive mood: F = 4.80, p < .05; self-esteem: F = 9.64, p < .01) and midadolescent boys (depressive mood: F = 12.27, p < .001; self-esteem: F = 9.38, p < .01) but not in early-adolescent boys or midadolescent girls. These findings are consistent with the hypothesis that body dissatisfaction is a risk factor for depressive mood and low self-esteem in both girls and boys but in different phases of adolescence.     

Effect of physical activity on bone turnover in young boys

AIMS: To evaluate the effect of the physical activity on bone turnover in young male soccer players at the Tanner's stage of 1-2. MATERIAL AND METHODS: 61 young soccer players (13,4 +/- 0,3 years old) who actively participated in soccer since 3,7 +/- 0,7 years were compared to 60 age and sex- matched non active subjects. Bone mineral density (BMD) of whole body, and in specific skeleton sites, fatty body mass (FBM) and lean body mass (LBM) were determined by a dual energy X-ray absorptiometry (DXA). Total plasma alkaline phosphatase (ALP) and plasma bone alkaline phosphatase (BALP), plasma osteocalcin (OC) and plasma collagen type I cross-linked C-telopeptide (CTX) were measured. RESULTS: BMD of the whole body and at the lumbar spine (L2-L4), femoral, lower limbs and LBM were significantly higher in young soccer players than in controls. The biochemical markers of bone turnover: ALP (6,7%), BALP (8,9%), OC (3%) and CTX (3,1%) were not significantly higher in sportsmen than in controls. The calcium was significantly higher in sportsmen than in controls. CONCLUSION: These results suggest that soccer practice induced an increase of bone mass in boys. The increase in the level of bone turnover evaluated by the new biochemical markers was not significant in the sportsmen.     

Vitamin E,exercise, and the recovery from physical activity

A matched-pair trial under near double-blind conditions has tested the physiological effects of an 85-day-course of d-α tocopherol acid succinate (1200 I.U./day) in 20 university class swimmers. Valid comparisons were possible in 7 of the 10 pairs. These showed good initial matching of maximum oxygen intake, recovery curves, muscle strength and e.c.g. waveform. Despite a substantial yardage of swimming training (～ 20,000 yards/week), neither test nor control groups improved their aerobic power. However, both groups showed a reduction in the lactate component of the oxygen debt, with a faster pulse recovery curve. Muscle strengths tended to decline, the loss of handgrip strength being significant in the control group. No change of e.c.g. waveform was observed except a small increase of T wave height in the controls. It is concluded that the swimmers gained no advantage from the Vitamin E, although it could conceivably have helped maintain equality of status in the face of a slightly smaller weekly yardage than that of the control group.     

Spectral and bout detection analysis of physical activity patterns in healthy,prepubertal boys and girls

Little is known about the frequency-intensity patterns of naturally occurring physical activity in children. A data set obtained previously by direct observation of physical activity in 8 girls and 7 boys (all prepubertal, ages 6–10) was analyzed with spectral analysis to detect significant frequency-intensity relationships. Pulse detection algorithms were used to characterize the number of exercise bouts, their duration and relative intensity. Spectral analysis revealed that physical activity bouts were frequent, pulsatile, and random with no significant frequencies detected during many 24-min periods of observation. An average of 83 ± 11 bouts per hour were observed in boys and 89 ± 12 bouts per hour in girls, and the mean duration of an exercise bout was 21 ± 5 sec for boys and 20 ± 4 sec for girls (NS). While high-intensity exercise bouts comprised less than 20% of the time spent in physical activity, duration of high intensity exercise bouts tended to be longer and accounted for about 40% of the energy expenditure associated with physical activity. Spontaneous physical activity in prepubertal children is characterized by frequent bouts of brief, mostly low intensity exercise, randomly interspersed with less frequent, but metabolically substantial high intensity bouts. These findings are potentially useful in assessing the impact of disease on quality of life in children, investigating the relationship between physical activity and mechanisms of growth and development, and creating new approaches for in-laboratory exercise testing in children. Am. J. Hum. Biol. 10:289–297, 1998. © 1998 Wiley-Liss, Inc.     

Prediction of physical activity level in adulthood by physical characteristics,physical performance and physical activity in adolescence: an 11-year follow-up study

The purpose of the study was to investigate to what extent the physical activity pattern in adulthood can be predicted by physical characteristics, performance and activity in adolescence. A group of 62 men and 43 women completed a questionnaire concerning physical activity during their leisure time at the ages of 16 and 27 years. An activity index produced from the questionnaire. At the age of 16 years, the subjects were also tested for strength (strength test battery) and running performance (9-min run). Maximal oxygen uptake ( ) was estimated from a submaximal test and a muscle biopsy specimen was taken and analysed for fibre types (percentages of types I, IIA, 1113). The proportion of subjects engaged in some kind of physical activity during their leisure time was approximately 70% among the women and 80% among the men at both ages. The time spent on physical activity (minutes per week) decreased with age for the men but not for the women. The women devoted less time. to physical activity than the men both at age 16 and 27 years. The attitude to endurance activities had changed to a more positive attitude among the women and to a less positive attitude among the men at age 27 years. The aerobic potential ( and percentage of type I fibre), running performance, strength performance, physical activity and marks in physical education at age 16 years explained 82% of the physical activity level in adulthood for the women and 47% for the men. The aerobic potential at age 16 years alone explained 31% of the adult physical activity level in the women and 24% in the men. Strength performance, physical activity and marks in physical education at age 16 years further increased the predictive value for the physical activity level in adulthood for the women but not for the men. It is suggested that the major portion of the variation in physical activity level in adult women, but not in the adult men, could be predicted from physical characteristics, physical performance, and the activity level in adolescence.     

Plasticity of adolescent growth in boys

The present analysis examines the plasticity of adolescent growth in 21 selected historic and recent growth studies from 6 European countries, the U.S., and Japan, during the last 150 years. Mean stature at the age of 6 years has significantly increased by approximately 6 mm per decade (P < 0.05), whereas adult stature has risen by approximately 10 mm per decade (P < 0.01). Developmental tempo has also increased. Mean age at take-off significantly dropped by approximately 2 years per century (P < 0.01), and age at peak height velocity by 1.7 years per century (P < 0.01). Yet, the secular trend affected different parts of the growth curves in a different way so that the shape of the growth curves has also changed. Whereas adolescent growth rose significantly in the last century (P < 0.01) and increasingly contributed to the improvement of adult stature, no significant modification of the prepubertal portion was evident. Though early childhood and adolescent growth appeared equally plastic, both parameters were statistically independent, indicating differences in the regulation of early and adolescent growth. Yet, the factors that regulate adolescent growth still remain to be elucidated. Am. J. Hum. Biol. 9:469–480, 1997. © 1997 Wiley-Liss, Inc.     

The delayed effects of prolonged physical exercise and physical training on cholesterol level

Summary The delayed effects of prolonged physical exercise on total and high-density lipoprotein (HDL) cholesterol were studied before and after a training period of 8 weeks. In 15 subjects, 1 and 2 days after a 3 h running test, total cholesterol was significantly lower than 1 day before and 8 days after the end of the exercise. One day post-exercise, HDL-cholesterol was significantly higher compared with 1 day before and 8 days afterwards. In ten subjects participating in the training program, decreased total cholesterol values were again found on the first day after the post-training exercise test. Total and HDL cholesterol levels were not significantly affected by 8 weeks of training.This work was supported by the Bundesinstitut für Sportwissenschaft, Köln     

Leisure-time physical activity behavior: structured and unstructured choices according to sex,age, and level of physical activity

The main goals of this cross-sectional survey were (a) to describe the associations between sex, age, and physical activity behavior and (b) to describe the age and sex-related associations with the choice of structured (formal) and unstructured (nonformal) physical activity programs. At baseline, data were selected randomly from 1,013 students, from the 7th to the 12th grades. A response rate of 73% (n = 739) was obtained. Accordingly, the sample of this study consisted of 594 adolescents (304 females and 290 males) with mean age of 15.9 years (range 13-20). Physical activity was assessed by means of a questionnaire. A questionnaire about leisure activities was applied to the sample to define the nominal variable “nature of physical activity.” The data showed that significantly more girls than boys (p ≤ .001) belonged to the sedentary group (80.7% girls) and low activity group (64.5% girls). Boys more frequently belonged to the more active groups (92.1%; p ≥ .001). The older participants were more engaged in formal physical activities, whereas the younger mostly chose informal ones whatever their level of physical activity. There were more significant differences in girls’ physical activity groups (X² = 20.663, p≤ .001) than in boys’ (X² = 7.662, p≤ .05). Furthermore, active girls chose more structured physical activities than their sedentary counterparts (18.8% vs. 83.3%). However, boys preferred unstructured activities regardless of physical activity group (83.7% vs. 58.5%; p ≤ .05). It can be concluded that as age increased, organized sports activities became a relatively more important component of total weekly activity for both male and female participants.     

Cardiac basal autophagic activity and increased exercise capacity

To investigate whether high-intensity interval training (HIIT) and continuous moderate-intensity training (CMT) have different impacts on exercise performance and cardiac function and to determine the influence of these exercise protocols on modulating basal autophagy in the cardiac muscle of rats. Rats were assigned to three groups: sedentary control (SC), CMT, and HIIT. Total exercise volume and mean intensity were matched between the two protocols. After a 10-week training program, rats were evaluated for exercise performance, including exercise tolerance and grip strength. Blood lactate levels were measured after an incremental exercise test. Cardiac function and morphology were assessed by echocardiography. Western blotting was used to evaluate the expression of autophagy and mitochondrial markers. Transmission electron microscopy was used to evaluate mitochondrial content. The results showed that time to exhaustion and grip strength increased significantly in the HIIT group compared with the SC and CMT groups. Both training interventions significantly increased time to exhaustion, reduced blood lactate level (after an incremental exercise test) and induced adaptive changes in cardiac morphology, but without altering cardiac systolic function. The greater improvements in exercise performance with the HIIT than with the CMT protocol were related to improvement in basal autophagic adaptation and mitochondria function in cardiac muscle. Mitochondria markers were positively correlated with autophagy makers. This study shows that HIIT is more effective for improving exercise performance than CMT and this improvement is related to mitochondrial function and basal autophagic adaptation in cardiac muscle.