In last month’s Peak Performance, nutrition writer Andrew Hamilton put paid to the notion that ribose might rival creatine for its ergogenic effects (PP197, May 2004, p6).

But this month a more promising candidate has been put forward in the shape of GACIK – a dietary supplement containing a mixture of amino acids and ketoacids.

A pair of US researchers set out to study the effects of GACIK supplementation on repeated bouts of anaerobic cycling performance, following an earlier study that showed the supplement significantly increased work output and delayed muscle fatigue during exhaustive isokinetic knee extensions.

Ten male college students, all of whom engaged in planned high-intensity exercise on at least three days per week, each performed two sessions of five supramaximal 10-second cycle ergometer sprints, one after supplementation with GACIK and the other after supplementation with placebo.

Both of these supplements were administered in three doses 45, 30 and 10 minutes before exercise. The two exercise sessions were separated by an average of seven days, and the five sprints were separated by rest intervals of one minute.

Analysis of the results revealed a significant difference between placebo and GACIK in the pattern of change in mean power output over the five sprints, with the decrease in mean power output between sprints 1 and 2 being significantly less with GACIK than with placebo.

‘The results of the present study indicate that GACIK ingestion significantly attenuates the drop in mean power output associated with repeated sprints of anaerobic cycling,’ state the researchers.

However, they are unable to explain precisely how GACIK exerts this ergogenic effect, especially as a similarity in post-exercise lactate concentrations after both GACIK and placebo appeared to rule out an effect on glucose kinetics.

They conclude, in the light of their own research and the previous findings mentioned earlier, that GACIK can serve as an ergogenic aid to improve muscle performance in repeated high intensity exercise.

‘These findings reinforce the notion that GAKIC supplementation may be a useful aid for strength-power athletes, similar to creatine supplementation,’ they say.

And they point out further: ‘Unlike creatine, which requires approximately 5 [days] of loading to produce improvements in high-intensity work, GACIK appears to impart an ergogenic effect within minutes of consumption. This presents an obvious advantage for GAKIC supplementation.’

However, further studies are needed to corroborate GACIK’s effectiveness and to determine whether its effects might be enhanced by being given in combination with creatine.

Med Sci Sports Exerc, vol 36, no 4, pp583-587