Gentle cardio training is definitely healthy for strength athletes. Twenty minutes of cardio training after a workout with heavy weights helps fight stiffening of the arteries, according to Japanese studies. Sports scientists at California State University in Fullerton discovered another reason for adding cardio to strength athletes’ routines. The researchers will publish soon in the Journal of Strength and Conditioning Research the results of a study in which moderately intensive cardio training helped to speed up recovery after a heavy strength workout.
Recovery is the main limiting factor in strength sport. Anyone with a bit of willpower can train muscles intensively – but unfortunately muscle growth requires not only training but also recovery. Pharmacologically supported athletes have an advantage over natural athletes in this respect. The substances they use speed up recovery.
If you search the literature for ways to speed up recovery after strength training you will mainly find studies on the effect of supplements such as ginger, tea, curcumin and, of course, BCAAs.
You also find studies in which alternate hot and cold baths are said to encourage muscle recovery. [Eur J Appl Physiol. 2008 Mar;102(4):447-55.] Interesting for athletes that have access to facilities, but not feasible for visitors to the average gym.
And you find studies that tell you what you already knew: that you recover faster from a weight training session if you build it up in the correct way, only starting on heavy sets once you’ve prepared your body. [J Sports Sci. 1997 Oct;15(5):477-83.]
In their study in the Journal of Strength and Conditioning Research, the researchers took a different approach: that of active recovery or “engaging in low-intensity exercise after competition or vigorous exercise sessions”.
Modest cardio speeds up post-weight training recovery
The researchers got 26 female students to do a killing workout on a leg-extension machine. The students had to do 6 sets of 10 eccentric reps. This kind of exercise causes severe muscle pain and considerable damage to the muscles too.
The control group did nothing after the leg extensions. [CON]
The first experimental group cycled for 20 minutes after the session, keeping the level of exertion low – at 30 percent of the maximal heart rate. [LIC]
A second experimental group also cycled for 20 minutes after the workout, but at moderate instead of low intensity. The women in this group cycled at 70 percent of maximal heart rate. [MIC]
The cardio sessions had no effect on the muscle pain the researchers learned when they asked the women to give their muscle pain a score during the days after the workout. The sessions also had no effect on the women’s dynamic strength: in this case the strength that the women developed during a complete movement on the leg-extension machine.
But, as you can see in the figure above, the cardio sessions did have a positive effect on isometric strength: the strength the women developed when they tried as hard as possible to perform a leg-extension on a fixed machine that was impossible to move. In the cardio groups, the decrease in isometric strength immediately after the workout was negligible – and in the MIC group it had even increased after a few days. And that’s an indication of accelerated muscle recovery.
The sessions are in line with the recommendations sports scientists make for strength athletes who want to include cardio training in their schedule. Review studies have shown that cardio training only reduces strength athletes’ progression if the sessions are longer than 25 minutes and done more than three times a week. [J Strength Cond Res. 2012 Aug;26(8):2293-307.]
The researchers suspect that cardio training done after strength training stimulates blood circulation. As a result waste products are removed more quickly from the muscles that have been trained while the nutrient supply also increases. That helps the muscle to recover faster.