Physical Activity, Fitness and the Energy Cost of Activities: Implications for Obesity in Children and Adolescents in the Tropics - Advances in Food and Nutrition Research - page 71

understand this relationship because both low fitness levels and physical inac-
tivity have been proven to be independent risk factors for various diseases
(cardiovascular disease, cancer, obesity) in childhood and adolescence
( Ortega et al., 2008 ).
4.3. PF studies conducted in the tropics
Compared to PA, only limited information is available for fitness perfor-
mance and its secular changes among children and adolescents in the tropics
in recent decades. In Thailand, there was an overall decline in the power test
performance, speed test performance, abdominal strength, and endurance
but not in upper-body strength among children 8-12-years old over a
13-year period (1990-2003) ( Klanarong, 2005 ) . A meta-analysis performed
by Macfarlane and Tomkinson (2007) summarized the secular changes in the
power, speed, and cardiovascular endurance test performance of over 23.5
million individuals 6-19 years old from seven Asian countries between 1917
and 2003. Only a small change in the power and speed test performance of
the Asian children and adolescents in recent decades was found; however, a
consistent decline could be observed in the cardiovascular endurance perfor-
mance of these young people across all the studied Asian nations over the
past 10-15 years.
A few studies have been conducted to compare the fitness levels of
children and adolescents in the tropics with their counterparts in other
regions. Ip (1991) compared the fitness performance of children 5-12 years
old in Hong Kong with the performance of children from the United
States, and the results indicated that children in Hong Kong, on average,
performed worse on the sit-up test (32% fewer) and 9-min run (7.2% less
distance) but were slightly more flexible than their American counterparts.
Huang (1994) reported that adolescents 12-14 years old in America out-
performed their Taiwanese counterparts in the 1-mile run. However,
another study that used the same fitness protocol showed that Taiwanese
boys were generally superior to their American counterparts for these fit-
ness measures; however, no significant differences could be observed
between the girls of both countries ( Su, 1993 ) . Another recent study
involving the comparison of fitness performance (20-m shuttle run test)
among children in 37 countries indicated that children in tropical coun-
tries, such as Hong Kong, Brazil, and Singapore, were classified as below
average compared to children from other regions, such as Northern Europe
( Olds, Tomkinson, L´ger, & Cazorla, 2006 ).