Resting May Be the Most Important Part of Your Workout

Supersets. Drop sets.  Strip sets.  Warm-up sets.  Working sets.

If there's one thing weight lifters know about - it's the importance of making every set count.  But what about making the most of the time in between exercises?  While techniques such as supersets are great for effective, efficient workouts, there's something to be said about slowing the pace down and taking your time.  As unbelievable as it may sound, doing nothing may do a lot for your performance in the gym.

So what are you sacrificing by rushing around the gym and minimizing rest time?  Strength.

A study published in the March 2008 issue of the Journal of Sports Conditioning and Research (1) compared the number of repetitions performed for barbell curl, shoulder press, leg press and leg curl with varying rest periods.  Across the board, the results were clear - a longer rest period resulted in the ability to perform more repetitions.  In fact, the number of leg press repetitions provided particularly significant findings; merely increasing the rest period from 30 to 60 seconds elicited a 66% increase in output.

But the improvements don't stop there.  A 1997 study subtitled "Fact Over Philosophy" (2) observed the differences between one and three minute rest periods on three sets of a 10 repetition maximum load during bench and leg press exercises.  Here, too, patience proved to be a virtue, as all of the test subjects were able to complete all three sets when allowed three minutes of rest; when resting only one minute, however, a "significant reduction" in total repetitions followed.

Surely, three minutes must be the masimum, right?  Resting longer than that would probably feel like a waste of time, but rest assured - it's not.  Yet another study (3) indicates that the bigger the lift, the longer the rest period should be in order to achieve optimal results.

The study by Willardson and Burkett, published in the JSCR in 2005, focused on the squat and bench press, with rest intervals of one, two and five minutes between sets.

Once again bigger proved to be better where rest periods were concerned.  Two minute rest intervals were preferable to one minute intervals in both exercises.  The improvements after the five minute rest periods were nothing short of amazing, though.  Total repetitions performed through four sets of the bench press showed potential improvements of 120 percent when the rest period was increased from one to five minutes.  Not a bad improvement for sitting around "doing nothing."

The cause of this phenomonen can be easily explained. 

Within your muscles are two types of fibers - slow-twitch and fast-twitch.  During resistance training, the slow-twitch fibers are activated at first, and the fast-twitch fibers take over once the slow-twitch fibers are exhausted. 

During rest periods, these fibers need to recover.  Unfortunately for you, the fast-twitch fibers are slower to recover than the slow-twitch fibers.  This is due to their tendency to accumulate more lactic acid than the slow-twitch fibers.  Lactic acid is a chemical formed as a by-product of the body breaking down glucose into energy during anaerobic activity.  When too much lactic acid builds up in your muscles, it can slow contractions and restrict range of motion. 

If insufficient time is provided between sets, the lactic acid does not have enough time to be cleared and thus hampers performance.  In this case, you'll be able to recruit the slow-twitch fibers on your next set, but the fast-twitch fibers will be all but ineffective, and you may find yourself struggling to crank out even half of the number of repititions you performed during the previous set.

But the story doesn't end there.  A 1987 study by Kraemer (4) concluded that when rest periods between sets are less than one minute long, the build-up of lactic acid was significantly increased. 

So we can reasonably conclude that it's better to err on the side of too much rest than too little.  Is there a point at which the increase loses effectiveness?  For all practical purposes, probably not.  In fact, a team of researchers (5) found that clearance of lactic acid could take up to ten minutes.  In other words, don't worry - taking a load off now may help you put more of a load on the bar later.

The next logical question is what exactly to do during your rest period.  Sure, there may be plenty of eye candy at the gym or perhaps you brought along a magazine, but neither of those will improve your strength at all.

As I mentioned previously, a major enemy in your war on the weight room is lactic acid.  Luckily, though, it is fairly easy to recruit some allies to assist in the reduction of lactic acid build-up in your muscles and help you reclaim your strength.

One option is to massage your muscles during rest periods.  The same March 2008 study that concluded one minute of rest was preferable to 30 seconds also compared the output of subjects when muscle massages were administered during rest periods.  While duration of the rest period seemed to be the biggest factor in strength in successive sets, subjects did perform more repetitions after having muscle massages than merely resting if the length of the period remained the same.

In addition to the obvious benefit of feeling good, massaging your muscles stimulates the lymphatic system.  This is very beneficial, as the lymphatic system carries waste products away from important sites in your body. 

Another benefit of massage is that it relieves hypertension and improves blood circulation.  Increased circulation results in more efficient delivery of oxygen and nutrients to your muscles, which means more power.  While there are many supplements that aid in vasodilation and better circulation, intra-workout massage is a free, easy option that delivers similar results.

While massage proved beneficial, the authors of the study suggested that active recovery would be an even better option.  Like massage, active recovery improves circulation ("keeps the blood flowing") and can help clear lactic acid from your muscles.  Active recovery has actually been shown to decrease lactate levels more quickly than complete rest.

Some active recovery techniques are stretching and low-intensity cardio.  While I don't recommend hopping onto a treadmill between sets of curls, you may find some benefit to walking around, jogging in place, or stretching during rest periods, particularly those of compound lifts such as squats and deadlifts.

Sources:

1. The Combined Acute Effects of Massage, Rest Periods, and Body Part Elevation on Resistance Exercise Performance. Caruso, John F; Coday, Michael A. Journal of Strength and Conditioning Research, 22: 575-582

2. A series of studies: The physiological basis for strength training in American football: Fact over philosophy. Kraemer, WJ. Journal of Strength and Conditioning Research, 11: 131–142

3. A Comparison of 3 Different Rest Intervals On the Exercise Volume Completed During A Workout. Willardson, Jeffrey M.;  Burkett, Lee N. Journal of Strength and Conditioning Research, 19: 23-26

4. Physiologic Responses to heavy-resistance exercise with very short rest periods. Kraemer, WJ; Noble, BJ; Clark, MJ; Culver, BW; International Journal of Sports Medicine, 8: 247-252

5. Effects of lactic acid accumulation and ATP decrease on muscle tension and relaxation. Sahlin, K; Edstrom, L; Sjoholm, H; Hultman, E. American Journal of Cell Physiology, 240: 121-126