International SportMed Journal - Volume 9, Issue 4, 2008
Volume 9, Issue 4, 2008
Author Jeroen SwartSource: International SportMed Journal 9 (2008)More Less
The past decade has seen an incremental increase in the popularity of cycle sports. In the traditional heartland of cycling, Europe, the sport has remained as popular as ever; however, it has increased dramatically in profile in previously non-cycling-orientated countries, such as the USA, Canada, South Africa, Australia, and recently, China.
Source: International SportMed Journal 9, pp 146 –154 (2008)More Less
This review provides an update on optimal carbohydrate intake strategies during prolonged exercise. The focus is primarily on the findings of studies performed in the past five years that have investigated the effect of multiple carbohydrate ingestion during prolonged exercise. Specifically, the emphasis is on the new findings related to the ingestion of carbohydrate drinks that contain more than one type of carbohydrate. The co-ingestion of either glucose or glucose polymer with fructose, or glucose, sucrose and fructose at a rate of 1.5 - 2.4g.min-1 during prolonged cycling results in significantly higher peak exogenous carbohydrate oxidation rates compared to ingestion of iso-energetic glucose or glucose polymer solutions. However, despite higher oxidation rates from the ingestion of mixed carbohydrate drinks, there is little evidence that this translates into improved performance.
Source: International SportMed Journal 9, pp 155 –161 (2008)More Less
The sport of cycling has been affiliated with doping for decades. Currently, the battle against doping has been intensified by the development and implementation of large-scale anti-doping programmes. The primary aim of this paper is, from a practical point of view, to describe the most efficient way of combating doping in cycling today. Of major importance is sample collection from the cyclists, which must be intelligently scheduled according to the substances tested for. A prerequisite for this is an efficient "whereabouts" system, and the collaboration between different testing bodies. Samples must be collected and analysed according to strict prescriptions thereby reducing the analytical variations, which are an essential part of individual longitudinal data comparison. Blood screenings can be performed on-site in a mobile laboratory allowing rapid follow-up testing, while urine must be analysed in one of the World Anti-Doping Agency (WADA) laboratories. The reporting of the sample collection must be extended to include information on potential confounding pre-analytical factors and the reporting of the analysis and test results must be streamlined and extended to include more quantitative data i.e. from the recombinant Human Erythropoietin (rHuEPO) test. In addition, a high level of education of the riders and transparency of test results will demystify the anti-doping activities for the riders as well as the public.
Potential causes of chronic anterior knee pain in a former winner of the Tour de France : case reportSource: International SportMed Journal 9, pp 162 –171 (2008)More Less
Little focus has been placed on the effects of cadence on pedalling action and subsequent risk of knee related overuse injuries. Ergometers with the capacity to measure torque throughout the knee extension cycle of each leg's pedalling motion (i.e. Computrainer ergometer with Spinscan function) have the potential to provide the clinician with additional insight into the causes of anterior knee pain in selected patients. A 32-year-old male professional cyclist and former winner of the Tour de France with a 7-year history of recurrent anterior knee pain presented to the authors' Sports Medicine Clinic with an acute exacerbation of anterior right knee pain following early season volume-based training. MRI findings were of a low grade patellar tendinopathy. Isokinetic testing revealed increased eccentric knee flexion strength of the right (injured) vs. left leg (213.4Nm vs. 166.3Nm). The rate of fatigue for right knee concentric endurance extension was greater than the left leg (22.8% vs. 10.1%). A Computrainer Spinscan analysis was performed at cadences of 65-, 75-, 85-, 95- and 105rpm respectively. Mean power balance (51.0 ± 0.9%) was in favour of the right leg. This abnormality in power balance was most prevalent at cadences lower than 75rpm (51.9 ± 1.5%). Mechanical efficiency scores for cadences below 85rpm (57.8 ± 3.8%) were significantly lower than recorded for other elite male road cyclists in these authors' laboratory (70-85%). Right leg mean torque angles were lower for all cadences (84.3 ± 3.0) in comparison to the left leg. This was accentuated for cadences of 85rpm or lower (82.3 ± 2.4). These findings were consistent with a low grade infra-patellar tendinosis attributable to force overload induced by high volume, low cadence activity.
Source: International SportMed Journal 9, pp 172 –181 (2008)More Less
The purpose of this study was to compare the differences in lactate parameters and maximal aerobic speed (MAS) adaptations to mixed and continuous training. Twenty-four subjects were equally divided into continuous (CT) (age 21.3± 1.2 years; body mass 69 ± 3kg; height 172 ± 2cm) or mixed (MT) (age 20 ± 2 years; body mass 68.5 ± 4kg; height 171 ± 3cm) training groups. Another six participants (age 21± 1.2 years; body mass 69.3 ± 3.4kg; height 174 ± 5cm) acted as non-training controls (CG). The trained participants practiced 6d/wk for 6 weeks. Before and after training, all participants completed an incremental exercise test to assess their MAS, and a 30 second supramaximal exercise followed by 30 minutes of active recovery. Blood lactate recovery curves from the supramaximal exercise were fitted to a bi-exponential time function. Following the training period, there was a significant increase in MAS, a significant increase in lactate exchange (γ1) and removal (γ2) abilities (P<0.001), a significantly faster time to peak lactate (t-[La]peak) (P<0.001), a significant decrease in lactate half time (t-½-[La]) (P<0.001) , and significantly higher lactate concentration at the beginning of the recovery for both the continuous and mixed training groups(P<0.05). The increases in MAS was significantly higher (P<0.001) in MT-group compared to CT-group (15.6 ± 3.1% vs. 10.3 ± 3.2%). The lactate-exchange ability was also significantly higher post-mixed than post-continuous training (0.606 ± 0.099 min vs. 0.548 ± 0.237min) (P<0.05). However, no significant difference was observed in the other lactate parameters. These authors conclude that both mixed and continuous training were equally effective in altering t [La]peak, t-½-[La] and γ2 ability, but mixed training was more effective in elevating both MAS and γ1.
Source: International SportMed Journal 9, pp 182 –183 (2008)More Less