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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 29, No 1, January/February 2018
32
AFRICA
A comparative study on the cardiac morphology and
vertical jump height of adolescent black South African
male and female amateur competitive footballers
Philippe Jean-Luc Gradidge, Demitri Constantinou
Abstract
Objective:
The aim of this comparative study was to deter-
mine the gender differences in cardiac morphology and
performance in adolescent black South African footballers.
Methods:
Anthropometry, electrocardiography and echo-
cardiography data were measured in 167 (85 males and 82
females) adolescent black South African footballers (mean
age: 14.8
±
1.3 years). Vertical jump height was used as a
performance measure of explosive lower-limb power.
Results:
The males had less body fat compared with the
females (12.1
±
3.6 vs 16.8
±
4.1%,
p
<
0.05), while females
had higher left ventricular end-diastolic diameters compared
with males (48.7
±
3.7 vs 40.7
±
8.1,
p
<
0.05). Vertical jump
height was higher in males (37.2
±
10.3) compared with
females (31.2
±
8) and was inversely associated with body fat
(
β
=
–0.2,
p
<
0.05) and positively associated with lean mass
(
β =
0.5,
p
<
0.05).
Conclusion:
The findings showed that adolescent black South
African male footballers had a performance advantage over
females for explosive lower-limb power, which was explained by
differences in body composition and not cardiac morphology.
Keywords:
adolescent, black South African, footballers, cardiac
morphology, vertical jump height
Submitted 25/7/16, accepted 13/7/17
Published online 15/8/17
Cardiovasc J Afr
2018;
29
: 32–35
www.cvja.co.zaDOI: 10.5830/CVJA-2017-032
Football is a popular sport, particularly among adolescents
in the developing world.
1
Adaptive changes to the heart are
assumed with chronic participation in football,
2
however little is
known of the cardiac morphology of African adolescents who
participate in this game.
3
Hypertrophy of the cardiac muscle is
the main consequence of training, contributing to the higher
level of performance compared with the sedentary, age-matched,
non-football population.
4
Although such cardiac adaptations provide clear physiological
advantages for the ability towithstandplay during the intermittent
nature of football, it is important to distinguish between the
physiological and pathological heart. Echocardiography and
electrocardiography are therefore important investigative tools
in football players, first to screen for and monitor at-risk players,
and second to monitor physiological development related to
football training.
5
Lower-limb dynamic functionality, particularly explosive
power during sprinting and jumping activities, is a key
characteristic of football.
6
These contribute to the speed and
strength demands of football performance movements.
7
It has
been reported that adolescent participants with congenital
heart disease produced lower peak jump heights compared
with age-matched ‘normal’ controls.
6
The converse is unknown,
namely whether optimal performance in these activities may
depend on the structural cardiac adaptations that follow football
training.
The aims of this comparative study were: (1) to determine
the gender differences in cardiac morphology and performance
in competitive adolescent South African footballers; and (2) to
determine the factors associated with explosive jump height and
measures of cardiac morphology in these footballers.
Methods
Data for this comparative study of adolescent black South
African footballers were collected from seven of the nine
provinces (the Eastern Cape, Free State, Gauteng, KwaZulu-
Natal, Limpopo, Mpumalanga and Western Cape). Participants
included were within the age range of 12 to 18 years, without
injury and actively involved in competitive amateur-level football.
Ethical clearance for the study was granted by the University of
the Witwatersrand (M140513).
Participants dressed with minimal clothing on the testing
day. No shoes were worn for the anthropometric measurements.
Height (m) was measured using a stadiometer (Seca 217, UK)
and weight (kg) was measured using a digital scale (Seca 844,
UK). Body mass index (BMI) was calculated as weight (kg)/
height (m
2
) and presented using BMI for age guidelines.
8
The Omron sphygmomanometer (Canada) and accompanying
stethoscope were used to measure systolic and diastolic blood
pressure (BP) with the participant in a seated position after five
minutes’ rest period. Three measurements were taken and the
average of the second and third BP measurements was recorded.
Skinfold measurements were used to determine proxy measures
of body fat and muscle mass using standardised methods.
9
Echocardiography was performed and measures of cardiac
morphology included interventricular septal (IVS) thickness,
ejection fraction percentage and left ventricular end-diastolic
Centre for Exercise Science and Sports Medicine
(CESSM), Faculty of Health Sciences, University of the
Witwatersrand, Johannesburg, South Africa
Philippe Jean-Luc Gradidge, MSc (Med), PhD, philippe.gradidge@
wits.ac.zaDemitri Constantinou, MB BCh, BSc (Med) (Hons), MSc (Med),
MPhil