Resistance training is one of the most important things you can do to enhance your quality of life at any age but especially as you get older. Even if you don’t want more muscle definition, resistance training is the key to preserving the muscle you already have. The old saying “use it or lose it” is spot on.
There are several approaches to resistance training. If your main goal is to build muscle strength, research shows you should use a heavy resistance for at least some of your sets, around 80 to 90% of your one-rep max. Then gradually increase the resistance over time as you become stronger. The key is to keep challenging your muscles to get them to grow.
For muscle growth, increasing the training volume and performing more reps stimulates the release of anabolic hormones that aid muscle hypertrophy. For muscle endurance, completing a high number of reps using a lighter weight isn’t ideal for increasing muscle size, unless you take the reps to near failure, but it does build muscle endurance. As you can see, there are a number of ways to adjust training variables to reach your goals. You can:
. Add more sets
. Increase the number of reps
. Change the angle at which you work the muscle
. Change the tempo at which you raise and lower the weight
. Add new exercises to your routine.
. Change the rest period between sets
. Change the order in which you do exercises
. Change the frequency with which you train
Are You Resting Long Enough Between Sets?
Recently, there’s been a movement toward circuit training, weight training with a short rest period between sets. The purpose of shortening the rest interval is to keep your heart rate up so you get some cardiovascular benefit and burn more calories. But, as a new study shows, if you’re trying to increase the size of your muscles, you might want to reconsider how you’re structuring the rest period between sets.
In a study carried out at the University of Birmingham in Alabama, researchers asked 16 healthy men to complete a series of resistance exercises with rest periods between sets of either one or five minutes. The exercises they did were four sets of leg presses and knee extensions at 75% of their one-rep max. Researchers then took a muscle biopsy immediately after the men worked out, 4 hours after, and again 24 and 28 hours after the exercise sessions. After each session, the men consumed 25 grams of whey protein.
What the researchers found was muscle protein synthesis was around two-times greater when the men rested for 5 minutes between sets than when they rested for only a minute. The longer rest period between sets, at least in this group of young men, was more effective at stimulating muscle protein synthesis. As you know, muscle protein synthesis is the driving force behind muscle growth.
Research suggests muscles increase in size in two ways: myofibrillar hypertrophy and sarcoplasmic hypertrophy. Myofibrillar hypertrophy is growth in the size of the contractile units of the muscle, which, in turn, makes the muscle stronger. Sarcoplasmic hypertrophy refers to an increase in the size of the liquid component of a muscle cell, the area where glycogen is stored and other components not directly involving in muscle contraction, including collagen and water.
An increase in muscle protein synthesis in this study suggests that new proteins are being laid down to form contractile elements. These functional elements will ultimately make the muscle stronger and larger – exactly what you want.
One study, published in the Journal of Strength and Conditioning Research, suggested that the best approach might be to use short rest periods between sets (30 seconds to a minute) when working dissimilar muscle groups and longer ones when training similar muscle groups.
All in all, this new study has limitations. For one, it’s a small study, only 16 men. Plus, the men were untrained and inexperienced in the world of weight training. The results could be different in women or experienced weight trainers who have already developed some degree of strength and muscle size. So, don’t take this study as gospel.
Choosing a Rest Interval
What rest interval should you use? If your main goal is to build strength, a 5-minute rest period between sets is ideal since longer rest periods give your muscles more time to recover so you can maximize the resistance or the number of reps you do on the next set. When building strength, you aren’t as concerned about eliciting a hormonal response. If you’re using lighter weights, it makes sense to keep your rest periods short, a minute or less. You won’t build significant strength or muscle size with light weights, so using a short rest period keeps your heart rate up and gives you a total body conditioning workout while enhancing muscle endurance. When your main objective is to grow a muscle, most people rest 2 to 3 minutes – but this study suggests that 5 minutes might be better. This is an approach you can try in your own training and see if it helps your muscles grow.
The Bottom Line
Always consider your goals when choosing your training variables. The rest period between sets is one of more than 6 training variables you can vary to augment the results you get. It’s also important to change these variables once your muscles adapt to continue to see growth. So, change it up at regular intervals.
Science Daily. “Extended Rest Between Weight-Lifting Sets Could Help Muscle Growth” May 3, 2016.
McKendry, J., Pérez-López, A., McLeod, M., Luo, D., Dent, R., Smeuninx, B., Yu, J., Taylor, Angela. E., Philp, A. and Breen, L. (2016), Short inter-set rest blunts resistance exercise-induced increases in myofibrillar protein synthesis and intracellular signaling in young males. Exp Physiol. Accepted Author Manuscript. doi:10.1113/EP085647.
J Physiol. 2012 Mar 1; 590(Pt 5): 1049-1057.
Published online 2012 Jan 30. doi: 10.1113/jphysiol.2011.225003.
Exerc Sport Sci Rev. 2007 Apr;35(2):50-5.
J Strength Cond Res. 2006 Nov;20(4):978-84.
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