Weighing in on racing: what are your goals?

those who regularly strength train while simultaneously trying to compete on the local racing circuit or for a team may benefit from a recent study's analysis of the "specificity of training" principle. The principle holds that combining two types of training (in this case, endurance with resistance training) compromises tissue adaptation, and therefore the body's response to either. The study, however, yielded some unexpected results.

Forty-five untrained men were assigned to 12 weeks of either: endurance training (ET)--running 2 or 3 times a week for 20 to 40 minutes, at between 65 and 80% of maximal heart rate; resistance training (RT)--upper- and lower-body weight lifting 2 or 3 times a week for 3 sets of between 6 and 10 reps at 75 to 85% maximal lift (at 1 rep); or concurrent training (CT)--performing the ET program 2 days and the RT program 3 days for one week, then switching to ET 3 days and RT 2 days the following week, and so on.

Unlike previous studies, the researchers took great care to ensure the ET aspect of the CT program exactly matched the ET program, and that the same was true for the RT and CT workout volumes. They hypothesized that RT and ET performed alone would produce greater gains in muscle strength and aerobic capacity (respectively) than CT. Two points of interest in the results emerge that differ from the researchers' expectations.

First the bad news. While the specificity of training principle has been demonstrated in many studies over the years, only one has found no improvement in peak aerobic performance in those who resistance train concurrently with endurance training--until now. The authors write, "The absence of any change in VO2peak in our CT subjects was unexpected, and conflicts with the majority of the concurrent-training literature." They are wary of making grand assumptions here, and are unconvinced that the aerobic response was not blunted by a high pre-training aerobic peak in their particular subjects, despite a randomized sample. In other words, it is possible that in what may be called a fluke, the subjects randomized into the CT group had already been near peak aerobic capacity when the trial started. Therefore, gains would be negligible. Nevertheless, it has been shown in the past that RT induces muscle hypertrophy, the consequence of which is diluted mitochondrial volume, which in turn could interfere with aerobic performance enhancement. This is, after all, one of the tenets of the specificity of training principle.

The second point of interest stems from the surprising result that subjects in the RT and CT groups made similar gains in maximum leg- and bench-press strength. The findings do not support the existence of a training interference phenomenon with respect to strength gains. This goes against the specificity of training principle as is relevant to getting the most out of your strength training workouts, and is good news for those whose focus is on distance racing well without sacrificing upper-body muscle strength.

We need more studies that follow the lead of the present study and carefully mitigate the differences between training programs to further scrutinize the import of the specificity principle, which now more than ever appears to be dependent upon individual fitness goals: Singularly, the CT group both significantly increased lean body mass and decreased body fat, while the RT and ET groups enjoyed these outcomes only respectively.

(Med. Sci. Sports & Exerc., 2004, Vol. 36, No. 12, pp. 2119-2127)