Today's maddening puzzler: Short on time as always, you enter the gym, dutifully warm up with 10 minutes of light cardio then hit the weights. You've heard you need rest between sets to maximize your strength training benefit. But the clock says you're late again. So: Do you skimp on the rest periods? Or do you cheat yourself out of a few exercises?
How about neither? A recent study appearing in the Journal of Strength & Conditioning Research concluded that people who rested three to five minutes between sets were able to lift 30 to 32 percent more on their second set than were people who rested one minute. Five minutes' rest did not yield a statistically significant gain over three minutes.
Sure, you could take a breather -- or you could use that time more productively.
_____The Moving Crew_____
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So: Three minutes is good. But doesn't that seem like an awfully long time to be mopping your brow or fiddling with your MP3 player?
Not if you use the time wisely. Study co-author Scott Richmond, a doctoral fellow in exercise science at Kansas University, said you could use those three minutes to work or stretch other muscles.
"You definitely don't want to work the same muscle group" during rest periods between sets, Richmond said. "One way to do it is alternate upper and lower body." So you could do a leg exercise like squats in between sets of a bench press. Or alternate an abs exercise with triceps kickbacks
For recreational lifters to maximize strength gains, they need to do two things: Lift "to failure," i.e., so the last repetition in each set is a struggle and you'd be unlikely to complete another rep in proper form. And they need to do the same number of reps in each of the two sets. (A third set doesn't yield as much benefit as a second one does. Time-pressed folks in pursuit of general health and fitness don't need a third set.)
In this well-controlled study, 28 men aged 18 to 24 each completed one set of eight to 12 bench presses to failure. Those who then rested one minute did not even reach eight repetitions in their next set, while the groups that rested three and five minutes each managed eight to 12 reps in set two.
If you're not pressed for time at the gym, kick back during your rest period. But if you'd rather be elsewhere sometime soon, you can do just about anything with that down time except two things: Work the muscles that are being stressed by the set at hand, or stretch them.
Data suggest that stretching may "disturb the elastic component" of muscle and thus limit its ability to hoist heavy weight, said William Kraemer, a kinesiology professor at the University of Connecticut and an expert on strength training.
Richmond said any other alternating activities are fair game.
Circuit training routines, like those at Curves gyms, are designed to work alternate muscle groups and thus do not require rest between stations. "These also help keep your heart rate elevated, and you actually get a minor cardio benefit," Richmond said.
You can perform your own circuit by choosing six to nine exercises, alternating body parts worked and performing them in sequence without rest. Then repeat the entire circuit.
Finally, some science we can twist to get you out of the gym quicker. Thank us later -- say, next Thursday, April 21, at our Moving Crew online chat. E-mail is firstname.lastname@example.org.
-- John Briley