carbohydrates

Carbos are just for endurance athletes, aren't they? Not necessarily - although there is little documented information on the relationship between carbo-hydrate ingestion and resistance exercise, it's common practice for weightlifters, body builders, powerlifters and other athletes involved in resistance training programmes to consume carbohydrate drinks with the hope of improving their performance

When intense exercise such as resistance training is performed, muscle glycogen (the body's carbo store) is an important energy source. One research study found a reduction in muscle glycogen of 26 per cent after resistance weight training. Experts once believed that glycogen was only used as a source of energy after stored ATP and phospho-creatine levels had been largely used up. However, it's now believed that exercise above 100% VO2 max will start drawing on glycogen energy stores virtually immediately. So far, measurements have suggested that reductions in muscle glycogen under these circumstances are not limiting, indicating that extra dietary carbohydrate (in the general diet, or as a supplement while exercising) would not bring about any benefit

However, some sports scientists have suggested there might be a more local effect within the muscle which is missed by measuring general glycogen levels - ie, that sub-groups of specific muscle fibres could become critically depleted of glycogen. To assess whether providing extra glucose would have any impact on resistance exercise, a research team at the University of Toledo studied seven experienced resistance athletes, to evaluate the influence of a glucose polymer ingestion on performance during a resistance training workout. On one occasion the athletes drank a 10 per cent glucose polymer solution immediately before exercise, while on another occasion a similarly coloured and flavoured placebo was drunk. The subjects were then required to perform leg extensions, starting with 10 repetitions on the first set, and defining a 'fatigue' endpoint as failure to perform seven repetitions for a set. There was a tendency for better performance after drinking the glucose polymer solution ('Effects of Carbohydrate Feeding on Multiple-bout Resistance Exercise', Lambert et al, Journal of Applied Sport Science Research, Vol 5,pp192-197)

The researchers concluded that for athletes performing prolonged resistance exercise (at least 15 sets of 7 to 10 reps) for a given muscle group, glucose polymer ingestion could allow a given exercise intensity to be maintained for a longer period of time. Thus, extra carbohydrate would be unlikely to have any effect on maximal strength, but could enhance training capacity. They also suggested that athletes involved in multiple-bout exercise might benefit from increasing the carbohydrate content of their general diet. The relationship between resistance exercise and carbohydrate fuel certainly merits further study