Abstract
The purpose of this study was to investigate the influence of cycling on sperm characteristics.
Twenty subjects volunteered for the study, comprising 10 long distance competitive
cyclists (median 25.5 y) and 10 sedentary controls (median 24.5 y). A questionnaire
was used to obtain a history of training, health, nutrition and life style. Semen
analysis consisted of a detailed evaluation of sperm characteristics that included
semen volume, sperm count, viability, motility and morphology. Compared to controls,
the cyclists had a significantly lower proportion of spermatozoa with normal morphology
(medians: 41.5 % versus 19.5 %; p < 0.01) and a significantly higher proportion of
morphologically abnormal tapered forms (medians: 4.5 % versus 22.5 %; p < 0.01). No
significant difference in semen volume and sperm motility, viability and count was
observed between the two groups. We concluded that endurance cycling appears to be
associated with a significant alteration in sperm morphology.
Key words
Morphology - exercise - cyclists - semen
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G. Rogers
School of Physiology · University of the Witwatersrand
Private Bag 3 · 2050 WITS · Johannesburg · South Africa
Email: rogersgg@physiology.wits.ac.za
