The following electronic only articles are published in conjunction with this issue of BJSM (see also page 69 and page 110)

Effects of training period on haemorheological variables in regularly trained footballers

Y Karakoc, H Duzova, A Polat, et al

Objective: To investigate the effects of one football training period on haemorheological variables in regularly trained footballers.

Method: Ten subjects were randomly selected from the reserve team of a football club in the Turkish Premier League. During the last week of the football season, one day before a standard training session and two days after the previous league match, venous blood samples were taken (pre-exercise). After 90 minutes of standard training, further blood samples were taken (post-exercise). Blood lactate, blood viscosity, plasma fibrinogen, blood clotting time, acid-base variables, and plasma Na⁺, K⁺, and Ca²⁺ were determined.

Results: Haemoglobin, packed cell volume, and mean corpuscular volume were all significantly decreased, whereas white blood cells and platelets were both increased after training. Blood viscosity decreased but the reduction was not significant. Blood lactate, plasma glucose, and Na⁺ content were significantly increased, but standard bicarbonate, actual bicarbonate, and Ca²⁺ were significantly decreased. Blood clotting time had shortened significantly after training. Blood viscosity was inversely correlated with plasma glucose concentration (r = −0.48 and p = 0.032).

Conclusions: The results show that blood viscosity tends to decrease as the result of this type of training. This is due to a reduction in packed cell volume and mean corpuscular volume. The increased blood lactate does not have an adverse effect on the blood viscosity of these subjects because protective mechanisms develop with regular training throughout the season.

(Br J Sports Med 2005;39:e4) http://bjsm.bmjjournals.com/cgi/content/full/39/1/e4

Differences in sole arch indices in various sports

S T Aydog, O Tetik, H A Demirel, et al

Background: There are controversial data about the relation between foot morphology and athletic injuries of the lower extremity. Studies in soldiers have shown some relationship, whereas those involving athletes have not shown any significant relationship. The reason for these differences is not clear.

Objective: To determine the effect of various sports on sole arch indices (AIs).

Method: A total of 116 elite male athletes (24 soccer players, 23 wrestlers, 19 weightlifters, 30 handball players, and 20 gymnasts) and 30 non-athletic men were included in this cross sectional study. Images of both soles were taken in a podoscope and transferred to a computer using a digital still camera. AIs were calculated from the stored images.

Results: The AI of the right sole of the gymnasts was significantly lower than that of the soccer players, wrestlers, and non-athletic controls (p<0.01). The AI of the right sole of the wrestlers was significantly higher than that of the soccer players, handball players, weightlifters, gymnasts, and non-athletic controls (p<0.03). The AI of the left sole of the gymnasts was significantly lower than that of the wrestlers and nonathletic controls (p<0.001). The AI of the left sole of the wrestlers was significantly higher than that of the soccer players, handball players, and gymnasts (p<0.007). The AI of both soles in handball players was significantly lower than those of the non-athletic subjects (p = 0.049). The correlation between the AI of the left and right foot was poor in the soccer players, handball players, and wrestlers (r = 0.31, 0.69, and 0.56 respectively), but was high in the gymnasts, weightlifters, and non-athletic controls (r = 0.96, 0.88, and 0.80 respectively).

Conclusion: The AIs of the gymnasts and wrestlers were significantly different from those of other sportsmen studied, and those of the gymnasts and handball players were significantly different from those of non-athletic controls.

(Br J Sports Med 2005;39:e5) http://bjsm.bmjjournals.com/cgi/content/full/39/1/e5