From Ergo Log
Strength athletes who also do cardio training will lose less progression if they cycle than if they run on a treadmill. On the other hand, treadmill training gives a bigger decrease in body fat, writes Jeff Gergley of Austin State University in the Journal of Strength and Conditioning Research.
Strength training makes you stronger, endurance training doesn’t. Endurance training increases your maximal oxygen uptake – the most powerful predictor of your cardiovascular health – but strength training has no influence on this. If overall fitness is your goal, you have to combine strength and endurance training, scientists and trainers agree. But the best way of combining strength and endurance training has not been studied.
To fill this knowledge gap, Gergley did an experiment with 30 untrained men and women, aged between 18 and 23. He divided the test subjects into 3 sub-groups, all of which trained for 9 weeks.
All groups trained their legs twice a week, doing leg extensions, leg curls and leg press. The first 3 weeks they did sets of 12 reps, then they did sets of 10 reps for another 3 weeks, and finally they did 3 weeks of sets of 8 reps.
The R group did nothing else. The RC group combined the strength training with cycling and the RT group combined it with running on a treadmill. The subjects did endurance training twice a week on the days that they didn’t do strength training.
The intensity was 65 percent of the subjects’ VO2max. For the first 3 weeks the RC and the RT groups trained for 20 minutes, then they trained for 30 minutes during the next 3 weeks and during the last 3 weeks they trained for 40 minutes.
The figure shows that the maximal strength increased most in the R group. The RT group made least progression and the RC group did a little better.
The fat percentage decreased most in the RT group and in the R group the least. Running simply costs more energy than cycling.
Perhaps we just have to accept that cardio training diminishes the progression you can make as a strength athlete. Whatever combination you choose, there will always be a trade off.
J Strength Cond Res. 2009 May; 23(3): 979-87.