Born to run: our future depends on it

PLoS ONE, 2013

The relative importance of genetic and socio-cultural influences contributing to the success of east Africans in endurance athletics remains unknown in part because the pre-training phenotype of this population remains incompletely assessed. Here cardiopulmonary fitness, physical activity levels, distance travelled to school and daily energy expenditure in 15 habitually active male (13.961.6 years) and 15 habitually active female (13.961.2) adolescents from a rural Nandi primary school are assessed. Aerobic capacity ( _ V VO 2 max) was evaluated during two maximal discontinuous incremental exercise tests; physical activity using accelerometry combined with a global positioning system; and energy expenditure using the doubly labelled water method. The _ V VO 2 max of the male and female adolescents were 73.965.7 ml . kg 21. min 21 and 61.566.3 ml . kg 21. min 21 , respectively. Total time spent in sedentary, light, moderate and vigorous physical activities per day was 406663 min (50% of total monitored time), 244656 min (30%), 75618 min (9%) and 82630 min (10%). Average total daily distance travelled to and from school was 7.563.0 km (0.8-13.4 km). Mean daily energy expenditure, activityinduced energy expenditure and physical activity level was 12.263.4 MJ . day 21 , 5.463.0 MJ . day 21 and 2.260.6. 70.6% of the variation in _ V VO 2 max was explained by sex (partial R 2 = 54.7%) and body mass index (partial R 2 = 15.9%). Energy expenditure and physical activity variables did not predict variation in _ V VO 2 max once sex had been accounted for. The highly active and energy-demanding lifestyle of rural Kenyan adolescents may account for their exceptional aerobic fitness and collectively prime them for later training and athletic success.

Scandinavian Journal of Medicine & Science in Sports, 2007

The aim of this study was to characterize Kenyan runners in regard to their oxygen uptake and blood and ammonia responses when rurtning. Untrained Kenyan boys (14.2-10.2 years) and Scandinavian runners were included for comparison. The studies were performed at altitude (-2.000 m.a.s.l.) and, for several Kenyan and Scandinavian runners, at sea level as well. At altitude sedentary adolescent Kenyan boys had a mean maximal oxygen uptake (Voz-u,) of 47 (4Ç51) ml'kg I 'min-r, whereas similarly aged boys regularly walking or running but not training for competition reached above 62 (58-71) ml .kg-r 'min I in Ver-"*. Kenyan runners in active training had 68+1.4 ml'kg-t ' rn¡n-t at altitude and 19.9-11.4 ml .kt-t .min-r at sea level, with individuals reaching 85 ml .kg l.min-I. The best Scandinavian runners were not significantly different from the Kenyan runners in V6r-u, both at altitude and at sea level, but none of the Scandinavians reached as high individual values as observed for some Kenyan runners. The running eff,ciency, determined as the oxygen cost at a given running speed, was less in the Kenyan runners, and the difference became more pronounced when body weight was expressed in ml .kg-ozs min-1. Blood lactate concentration was in general lower in the Kenyan than in the Scandinavian runners, and the Kenyans also had extremely low ammonia accumulation in the blood even at very high exercise intensities. It is concluded that it is the physical activity during childhood, combined with intense training as teenagers that brings about the high V6r-u, observed in some Kenyan runners. Their high aerobic capacity, as well as their good running economy, makes them such superior runners. In addition, their low blood lactate and ammonia accumulation in blood when running may also be contributing factors.

Objectives: To study the effects of urbanization on physical fitness (PF), we compare PF between urban and rural children from western Kenya. We hypothesize that active rural children are stronger, more flexible, and have greater endurance, and that PF differences are predictive of endurance running performance. Methods: We recruited an age-matched, cross-sectional sample of participants (55 males, 60 females; 6–17 years) from schools near Eldoret, Kenya. PF and anthropometrics were assessed using the FITNESSGRAMV R. General linear mixed models (GLMM) and path analyses tested for age, sex, and activity group differences in PF, as well as the effects of PF variables on mile run time. Results: On average, urban participants had greater body mass (36.8 6 15.9 vs. 31.9 6 10.9 kg) but were not taller than rural participants (1.4 6 0.2 vs. 1.4 6 0.2 cm). Greater urban body mass appears driven by higher body fat (28.2 6 9.4 vs. 16.8 6 4.4%), which increased with age in urban but not rural participants. GLMM analyses showed age effects on strength variables (P<0.05) and sex differences in hip flexibility, sit-ups, and mile run (P<0.05). There were few differences in PF between groups except rural participants had stronger back muscles (18.2 6 4.5 vs. 14.18 6 4.3 cm) and faster mile times (6.3 6 0.7 vs. 7.9 6 2.0 min). Body composition and abdominal strength were pre-dictive of mile time (P < 0.06), but the path analysis revealed a network of interacting direct and indirect effects that influenced endurance performance. Conclusions: Although differences in endurance and body composition are marked between urban and rural groups, strength and flexibility are not always correlated with overall activity levels. Am.

Medicine and Sport Science, 2007

Adelaide SA 5001 (Australia) Bibliographic Indices. This publication is listed in bibliographic services, including Current Contents ® and Index Medicus.

Medicine & Science in Sports & Exercise, 2003

Purpose: This study compares the training characteristics and the physical profiles of top-class male and female Kenyan long-distance runners. Method: The subjects were 20 elite Kenyan runners: 13 men (10-km performance time: 10-km performance time of 28 min, 36 s Ϯ 18 s) and 7 women (32 min, 32 s Ϯ 65 s). The male runners were separated into high-speed training runners (HST: N ϭ 6) and low-speed training runners (LST: N ϭ 7) depending on whether they train at speeds equal or higher than those associated with the maximal oxygen uptake (vV O 2max ). All but one woman were high-speed training runners (female HST: N ϭ 6). Subjects performed an incremental test on a 400-m track to determine V O 2max , vV O 2max , and the velocity at the lactate threshold (vLT). Results: Within each gender among the HST group, 10-km performance time was inversely correlated with vV O 2max (rho ϭ Ϫ0.86, P ϭ 0.05, and rho ϭ Ϫ0.95, P ϭ 0.03, for men and women, respectively). HST male runners had a higher V O 2max , a lower (but not significantly) fraction of vV O 2max (FV O 2max ) at the lactate threshold, and a higher energy cost of running (ECR). Among men, the weekly training distance at vV O 2max explained 59% of the variance of vV O 2max , and vV O 2max explained 52% of the variance of 10-km performance time. Kenyan women had a high V O 2max and FV O 2max at vLT that was lower than their male HST counterparts. ECR was not significantly different between genders. Conclusion: The velocity at the V O 2max is the main factor predicting the variance of the 10-km performance both in men and women, and high-intensity training contributes to this higher V O 2max among men.

Frontiers in Public Health

Background: Physical inactivity and low cardiorespiratory fitness (CRF) are independent cardiovascular risk factors among children, but have rarely been investigated concurrently in sub-Saharan Africa. The purpose of this study was to compare physical activity (PA) and CRF of primary schoolchildren living in Côte d&#39;Ivoire (CI), South Africa (ZA), and Tanzania (TZ), to test sex- and age-related differences, and to examine whether PA and CRF are associated with each other.Methods: Baseline data from an ongoing cluster-randomized controlled trial were used, including 499 children from CI (Taabo, 49% girls, M = 8.0 ± 1.6 years), 1,074 children from ZA (Gqeberha, 49% girls, M = 8.3 ± 1.4 years), and 593 children from TZ (Ifakara, 51% girls, M = 9.4 ± 1.7 years). PA was assessed by accelerometry and CRF by a 20 m shuttle-run test. The data were analyzed using multi-/univariate analyses of variance and mixed linear models.Results: Most children met recommendations put forward by the Wo...

Journal of Sports Sciences, 2006

Kenyan athletes have dominated international distance running in recent years. Explanations for their success include favourable physiological characteristics, which could include favourable genetic endowment, and advantageous environmental conditions. The aim of this study was to compare the demographic characteristics of elite Kenyan runners with those of the general Kenyan population. Questionnaires, administered to 404 elite Kenyan runners specializing in distances ranging from the 800 m to the marathon and 87 Kenyan controls, obtained information on place of birth, language, and distance and method of travel to school. Athletes were separated into two groups according to athletic success: those who competed in international competition and those who competed in national competition. The athletes differed from controls in regional distribution, language, and distance and method of travel to school; athletes also differed from each other with the exception of method of travel to school. Most national and international athletes came from the Rift Valley province (controls 20%, national athletes 65%, international athletes 81%), belonged to the Kalenjin ethnic group (controls 8%, national athletes 49%, international athletes 76%) and Nandi sub-tribe (controls 5%, national athletes 25%, international athletes 44%), and spoke languages of Nilotic origin (controls 21%, national athletes 60%, international athletes 79%). A higher proportion of all athletes ran to school each day (controls 22%, national athletes 73%, international athletes 81%) and covered greater distances. In conclusion, Kenyan runners are from a distinctive environmental background in terms of geographical distribution, ethnicity and travelled further to school, mostly by running. These findings highlight the importance of environmental and social factors in the success of Kenyan runners.

African Journal for Physical, Health Education, Recreation and Dance, 2015

The purpose of this study was to determine the cardiovascular fitness of pediatric population in central Kampala, Uganda. A stratified random sampling was used to select 1929 pupils aged 6-9 years in Wakiso and Mukono districts. A pre-experimental design was used to collect data on the cardiovascular fitness endurance using a 9-minute distance run/walk test. Pupils in day schools had significantly higher mean score (1538.02±309.09) for the 9-minute distance run/walk than those in boarding schools (1486.27±305.22). There was significant gender difference in cardiovascular fitness endurance with boys recording higher mean score (1591±356.76) than girls (1440.64±236.72). Majority (71%) of pupils met acceptable cardiovascular fitness endurance according to percentile norms set by American Association of Health, Physical Education, Recreation and Dance (AAHPERD). About 18.8% and 10.1% had weak and critical cardiovascular endurance status, respectively, which necessitated intervention. Pu...

American Journal of Human Biology, 2012

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 VO 2 max). 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 21 kg 21 , respectively). CRF was similar in all three populations ($38 and $43 mlO 2 Ákg 21 min 21 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 (26.0 and 211.9 kJ day 21 kg 21 per 10-year age difference in women and men, respectively) and for CRF in Maasai men (24.4 mlO 2 Ámin 21 kg 21 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.

Background: Kenya's 2016 report card aimed to highlight the health and well-being of Kenyan children and youth using the best available evidence on the physical activity of Kenyan children and youth. The report pointed at areas where Kenya was succeeding and areas where more action is required. Methods: Inclusive analyses of available data sources on the core indicators related to physical activity and body weights of Kenyan children and youth (5 to 17 years) were conducted. These were assigned grades based on a set of specific criteria. Results: Results show that Active Play, Active Transportation, Overweight and Obesity, and Sedentary Behavior were favorable with a grade of B. Overall Physical Activity, Organized Sport Participation, and School (infrastructure, policies, and programs) each received a grade of C, while Family and Peers, Government and Nongovernment organizations, as well as the Community and the Built Environment were assigned grade D. Conclusions: Over 72% of Kenyan children and youth use active transportation to and from school and in their daily lives. Although majority of the children and youth have normal body weight, there is need to ensure that they meet and maintain the physical activity levels recommended by the World Health Organization. More needs to be done especially in relation to the governmental and nongovernmental organizations, organized sports participation, as well as involvement of family and peers in promoting healthy active lifestyles among Kenyan children and youth. More representative data for all indicators are required in Kenya.