When designing a resistance training program for optimal gains, you can manipulate four main variables: training intensity, training volume, how frequently you train and rest periods. Adjusting these parameters helps you track your training as well as follow a program that helps you meet your goals. Training frequency and rest period length are pretty straightforward, but training volume and intensity are a little trickier. Let’s look more closely at these variables, what they are, how they impact your training and how to track them.
Training volume is a measure of the total amount of work you do during a single session or on a weekly or monthly basis, depending upon how you want to track it. Simply put, training volume is the total amount of weight lifted during a single session. For example, assume you did 3 sets of biceps curl and completed 10 repetitions for each set. You did the first set at 15 pounds, increased to 20 pounds for the second set and to 25 pounds for the third set. Your training volume for that set would be:
15 x 10 = 150
20 x 10 = 200
25 x 10 = 250
Therefore, your total training volume for biceps curls was 600 pounds. To get your total training volume for a session, simply add up the total pounds lifted for each exercise based on the weight you used, the number of reps you completed and the number of sets.
When measuring training volume, you can track how much volume you’re doing on a daily basis, a weekly basis or a monthly basis or break it down into how much volume you’re doing for each muscle group, body part or per exercise.
As your muscles adapt to your current training schedule, you can increase the volume to give your muscles further stimulus to grow. Do this slowly to avoid overtraining the muscles you’re trying to build. One thing to remember is total training volume doesn’t take into account factors like how you’re spacing your workouts. If you try to force a week’s worth of training into three days rather than spacing your workouts out over an entire week, your muscles will feel greater stress due to lack of recovery time even if the volume doesn’t change.
Another problem with tracking training volume using the above formula is it’s easier to achieve higher volumes on some exercises as opposed to others. So, the standard method of tracking training volume doesn’t differentiate between how hard or easy an exercise is to do.
Training Intensity – What Does It Mean?
Another way to change the stimulus on your muscles is to alter training intensity. One way to look at intensity is how the weight you’re lifting compares to your one-rep max. One-rep max is the amount of weight you’re capable of lifting with decent form for a single repetition. If you’re lifting 50% of your one-rep max, the intensity is lower than if you’re using a weight that’s 90% of your one-rep max. In the first situation, you can do more reps, but the intensity is so low you’re focusing on muscle endurance. In the second case, the number of reps you can do will be lower due to the higher intensity and you’re targeting strength, assuming you’re taking sets to near failure.
One problem with defining intensity this way is it doesn’t take into account individual variations in training ability. For example, someone with a high ratio of fast-twitch to slow-twitch fibers won’t be able to do as many reps as a person with predominantly slow-twitch when using a moderate load since fast-twitch muscle fibers fatigue faster than slow-twitch. Some trainers argue that the “rate of perceived exertion” when lifting a particular load is a better measure of intensity, but that has a subjective component to it that’s harder to measure.
You can look at strength, endurance and hypertrophy gains on a continuum. At one end of the continuum is strength, where the focus is on high-intensity loads, 85% or more of one-rep max. At the other end of the spectrum is endurance where you’re training at an intensity of 40 to 60% of one-rep max. In between is hypertrophy where the target intensity around 70 to 80% of your one-rep max. As you increase the intensity, the volume or number of reps you can do goes down.
Training frequency refers to how often you train. When you consider that muscles need 24 to 48 hours to recover between sessions, there are limits to how many sessions you should do weekly. If you do a split routine where you train upper body one day and lower body the next day, you can train as often as 5 times a week because one muscle group is recovering while the other is training. If you train your entire body in a single session, training frequency should be lower, no more than 3 sessions weekly.
As you become more advanced in your training and have built up a certain level of muscle strength and endurance, you can manipulate your sessions so you’re training more frequently, while still allowing your muscles adequate recovery time, but there are limits to how much you can increase frequency without overtraining and interfering with muscle growth. The quantity of time you have available to train and age are also factors. Once you get past a certain age, your muscles may need more recovery time between workouts.
There seems to be a minimum training frequency you need to make gains. You’re probably not going to see significant changes if you only train once every 10 days. On the other hand, some research shows training as little as once weekly is enough to build and maintain strength and is as effective as training twice a week, although more frequent, higher volume training is more conducive to building muscle mass.
Rest Periods between Sets
Finally, you can alter how much time you rest between each set. If you’re targeting strength and lifting at a high percentage of your one-rep max, rest periods will be longer, between 3 to 5 minutes, to allow your muscles to recover enough to maximize the amount you lift on the next set. When you’re lifting at such a high intensity, you quickly get lactic acid build-up and a drop in ph. Plus, you’re using the creatine phosphagen energy system primarily for short, intense sets and it needs several minutes to recover so you have the ATP you need for the next set. Without enough recovery time, your performance on the next set will be sub-maximal.
If you’re training for hypertrophy, rest periods can be shorter. As a general rule of thumb, rest for about the same length of time that it took for you to do the set. If you completed a set in a minute, rest 60 seconds before doing the next one. According to the International Sport Association, using a 1:1 ratio maximizes hypertrophy gains when using a weight and volume appropriate for building mass, about 70 to 80% of one-rep max.
If you’re using light weights, consistent with endurance training, rest periods are generally very short, less than a minute and sometimes as little as 30 seconds. Because you’re not letting your muscles fully recover, strength gains will be minimal, although you’ll get more cardiovascular benefits due to the short rest periods.
The Bottom Line
Manipulating these four variables lets you change the stimulus you place no your muscles to achieve the goal you set, whether it be gains in strength, hypertrophy or muscle endurance. Tracking these parameters also lets you see how you’re progressing and make changes over time to get into the best shape possible.
Concepts of Athletic Training. Fourth Edition. Pfeiffer and Mangus. 2005.
J Sports Med Phys Fitness. 2007 Mar;47(1):13-7.
Br J Sports Med. 2007 Jan;41(1):19-22. Epub 2006 Oct 24.
International Sport Association. “Rest periods Between Sets: Everything you ever needed to know!”
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