Aerobic Exercise During the Interset Rest Period

As part of my membership with the National Strength and Conditioning Association (NSCA), I am subscribed to the Strength and Conditioning Journal that publishes research studies on varying topics from the health and fitness field.

The latest addition has a brief review on an interesting topic that has piqued my interest, especially since I am currently making my way through my mass phase. Mohamed, Cronin, and Nosaka discuss "Maximizing Hypertrophic Adaptation - Possible Contributions of Aerobic Exercise in the Interset Rest Period." In laymen's terms, the potential for increased hypertrophy (muscular growth), by using light aerobic exercise between sets rather than just 'passive' rest.

The article discusses the factors involved in hypertrophy. Progressive overload, specific repetition ranges, muscular "time under tension", as well as interset rest periods. Some research has shown that decreased rest periods increase the metabolite buildup in the working muscles and blood stream, which can further increase the affinity for hypertrophy. By using a 1:1 to 1:2 work to rest ratio, individuals can increase their blood metabolite concentrations and force their bodies to not only adapt to the training stimulus, but to increase hypertrophy gains. The one downside to this technique, however, is that as individuals increase their workload or resistance levels, insufficient rest periods can result in decreased force production.

It does not take a rocket scientist to realize that by increasing rest periods between sets, individuals can therefore increase their force output. However, rest periods should be specifically designed to target a specific training goal, no different than repetition range goals, load goals, and "time under tension" intervals. If you were to do a set of chest presses, then go eat lunch and take an hour off, when you return to do a 2nd set of the very same chest press, your body will most certainly have recovered 100% to return and produce similar force outputs. This is not only an inefficient way of working out, but it is also not beneficial for muscular gains, especially in regards to hypertrophy.

Resistance training is a high-force output style of exercise, therefore most of us would be led to believe that the anaerobic energy systems supply 100% of the energy needed. This is simply not true, as triglyceride (fats) levels have been shown to decrease in muscle cells following resistance exercise (lipolysis - utilization of lipids/fats) indicating the fact that aerobic energy systems are at least part of the energy equation.

Although the aerobic energy systems are partially at work here, majority of the force produced during resistance training comes from anaerobic energy stores. This is the primary reason for interset rest, so that the body can 'top-up' its energy stores with 60-120 seconds of rest. Mohamed, Cronin, and Nosaka have studied and discussed the theory that light aerobic exercise between sets can have a number of positive effects on the human body, increasing the affinity for strength and hypertrophic gains. They present a table with proposed benefits to various systems in the body:

Mechanical - Optimize muscle temperature for greater force and velocity output, increase elasticity of muscle for increased work output (force x distance), and improve mechanical efficiency (ratio of energy turnover and mechanical output)

Metabolic - Improves lactate clearance rate and rate of energetic repletion

Hormonal - Greater total anabolic hormone production

Neural - Increase motor unit recruitment, firing frequency, synchronization and reflex potentiation, synergistic contribution, and co-contraction of antagonist

By using very light (50-60% maximum heart rate) aerobic exercise, it is possible to increase the efficiency of rest periods, allowing great hypertrophic gains. If one is to explore this avenue, then you should aim for aerobic exercise that targets the generalized area that has been worked on. For example, if you are training your legs, and have just come off of a set of heavy back squats, some light activity on an exercise bike or jogging can elicit this benefits. Similarly, if working the upper body, using a rowing machine or arm ergometer can improve recovery and circulation to the desired muscles.

This is definitely something that I will explore on my own and test out in my own workouts as the benefits gained sound very plausible.

Sources:
http://journals.lww.com/nsca-scj/Abstract/2012/02000/Brief_Review__Maximizing_Hypertrophic.2.aspx

Photo - http://www.kalisthenixfitnessblog.com/2008_09_01_archive.html

Periodization

Traditional periodization models are broken down into cycles. Macrocycles are the largest and usually involve an entire sport year, but can last up to 4 years for an Olympic athlete for example. Macrocycles are made up of 2 or more mesocycles which can last anywhere from several weeks to several months. Going further beyond that, mesocycles are broken up into microcycles which are usually a week long but can be as long as 4 weeks each.

To properly train any athlete, a well-structured training program will consist of both sport-specific training as well as strength and conditioning training. The emphasis placed on either training modality is entirely based on where the individual stands in not only their sport season, but also in their physical conditioning. Periodization involves shifting from non-sport specific training (strength and conditioning), that is of high volume and low intensity to low volume, high intensity sport-specific activities. This shift will occur over a period of many weeks to prevent overtraining and optimize performance.

The following image will detail the periodization periods

Preparatory Period

The preparatory period is the longest period and usually occurs at the time of year furthest from time of competition. This is the time for the athlete to establish a base level of fitness in order to build and grow from there. Slow, long distance running, light plyometrics, low resistance, high-repetition resistance training is all needed and utilized to begin conditioning.

When the preparatory period first begins and the training loads are high (long distance running/swimming, high repetition resistance training), the strength and conditioning sessions take a longer period of time, which leads to fatigued athletes that have little time for sport-specific training. As the preparatory period nears the end, the microcycles begin to change to lower the work volume, increase intensity (resistance loads), and increase sport-specific training.

The goals early on in the preparatory period should be to improve muscular endurance and hypertrophy. This goal is in place to increase the efficiency and size of the muscles so that they can then be honed and trained later. To train your muscles for endurance and hypertrophy, the individual should aim for 50-75% of their 1 rep maximum (1RM) which should result in a 10-20 repetition range. The hypertrophy/endurance phase should last anywhere between 1-6 weeks and then a low-intensity recovery week before transitioning into a basic strength phase.

Now that the individual has increased their muscular size and efficiency, the basic strength phase is designed to do just what it says and improve the overall strength of said muscles. The basic strength phase involves high intensity (80-90% 1RM) and moderate volume of 3-5 sets of 4-8 repetitions.

After the basic strength phase, the athlete can then transition into the strength/power phase. This is where high loads and low volumes are introduced to maximize the explosiveness and power in the muscles. The strength/power phase involves high intensity (75-95% 1RM) and low volume of 3-5 sets of 2-5 repetitions.

First Transition Period

A very short period, the transition period is designed to allow the body to heal and recover with one week of lower intensity, lower volume, or a combination of the two to prepare the athlete for the competition period.

Competition Period

Competition periods can last for a week to several weeks, although most athletes have a sport or competition season that can last for many months. During this time, the goal of the individual is to maintain their current strength and conditioning levels by continuing to train with high intensities, but greatly reduced volumes. Especially important during this time is that the sport-specific skills are honed and trained in order to "cash-in" on the training that has been completed in the preparatory period.

Another main goal of the athlete is to ensure that their strength and conditioning peaks during competition so that they maximize the return from the efforts they have put into their training up until this point.

Second Transition Period (Active Rest)

During this period, the goal of the athlete is to allow their bodies to rest and recover from a lengthy "peak" period during their competition season. Various light to moderate activities can be practiced as long as the body is not stressed or strained too hard. It is entirely possible for the individual to not have any resistance training at all.

-Tyler Robbins
B.Sc. PTS