While there are countless variations of volume and intensity in resistance training programming, a commonly under-appreciated variable of periodization is training frequency. I first became interested in the subject about a year ago when I decided to try a high-frequency squat program to help me break a plateau I was in and saw incredible progress. I not only broke through my plateau, but it seemed as if I was setting PR’s almost every other day. The more I explored the subject, the more fascinated I became. Today we will be discussing the efficacy and considerations for athletic performance.
The Norwegian Frequency Project
Many of you have likely heard of what is often referred to as the Norwegian Frequency Project. The study consisted of 16 elite competitive powerlifters, half men, and half women, between the ages of 18 and 25. They were split into either a high frequency (6day/wk) training program or low-frequency ( 3day/wk) training program with the same exercises, routine and weekly volume held constant between the groups. The high-frequency group had nearly double the strength and hypertrophy gains as the low training frequency group. It is important to note that these were not your everyday gym goer. The participants in this study were highly trained national level Norwegian powerlifters. This study has sparked a lot of interest in high-frequency training programs. It is my goal to speak about what the limited research indicates the efficacy of these high-frequency programs and who they are best suited for.
Effects on Neuromuscular Strength
First, let’s look at the possible effects of high-frequency programs on gains in neuromuscular strength. The literature is split on the benefits of high-frequency training on strength gain. Some studies have shown no significant difference between high and low-frequency groups, but have not recruited highly trained individuals who are going to respond similarly simply due to their lower training age. Other studies have shown significantly greater strength gains for high-frequency training groups, but have failed to control for total weekly volume. Overall, however, the literature seems to indicate superior neuromuscular adaptations to high-frequency resistance training programs. High-frequency training’s effects on strength over other types of training are likely due to:
- Reduced fatigue and therefore greater quality of repetitions
- Increased frequency of stimulus
- Increased muscular cross-sectional area
Fatigue and Training Quality
Due to the lower daily volume of high-frequency resistance training programs, it is possible for quicker recovery following training bouts and a reduced accumulation of fatigue that could hamper performance. Neural strength gains occur through several mechanisms including increases in motor unit recruitment, motor unit synchronization, rate coding and motor learning[3, 4]. We also know that strength gains are specific to the contraction type, posture, movement pattern and movement velocity [5-7] and that structural and physiological changes in the motor cortex are experience specific .. With less daily fatigue greater velocities and technical proficiency can be attained during a training session providing higher velocity and quality of repetitions that could lead to greater and more specific adaptation. Also, reduced fatigue will reduce the likelihood of compensation that could lead to injury.
Frequency of Stimulus
It has been suggested that, due to the complex interplay between many different neurological components in movement, that strength and skill acquisition may be more closely related than we have previously believed. One study found significant strength gains simply through imagining maximal contractions 5 times per week for 4 weeks suggesting increases in strength through central motor programming and planning. It is possible that, like learning other skills, frequent practice will contribute to greater efficiency and neurological adaptations that could lead to an increase in performance.
Muscular Cross-Sectional Area
Finally, strength may be increased due to increases in muscle cross-sectional area as studies have found that high-frequency training yields greater increases in muscle hypertrophy than low-frequency training at equal volumes. A review by Soares et al. found that a more frequent stimulus seemed to provide greater neuromuscular adaptations, but that the benefits for trained individuals may be more closely related to the hypertrophic effect of high-frequency programs.
Effects on Muscular Hypertrophy
In the Frequency Project, they found that the elite powerlifters participating in the high-frequency training showed nearly double the increase in muscle cross-sectional area as the low-frequency group. Other studies have shown similarly improved hypertrophic response to high-frequency training with a meta-analysis of the data on intensity, volume and frequencies effects showing that, while very few studies have utilized frequencies greater than 3-4 days per week, the study with the highest frequency (12 times per week) showed the greatest rate of muscular hypertrophy of .55% daily compared to .11% daily on average. These results, however, could have also been affected by differences in training methods. In general, however, most studies show greater increases in hypertrophy training muscles 3-4 times per week than 1-2 times[10, 12, 13].
Muscular Protein Synthesis Threshold
It has been hypothesized that the body has a threshold for increases in the rate of muscle protein synthesis following a single bout of exercise. If true, then increases in volume after reaching this threshold would provide no further benefit to muscular development, while also increasing the demands for recover on an athlete. If an athlete were to have a reduced daily volume, but a higher frequency of training, they would have an increased consistency of improvement in muscle protein synthetic rate, while keeping recovery demands reduced, therefore, allowing for greater net increases in muscular hypertrophy. This effect, however, is believed to be more relevant to trained individuals than untrained individuals. Those with a low training age may benefit from increased muscle protein synthesis for up to 72 hours post-training bout, whereas trained individuals show a blunted muscle protein synthetic response of closer to 24 hours[12, 14].
Detraining and Accommodation
One common concern I have heard from people when discussing high-frequency training is what happens if you decide to stop training as frequently? Do the gains you made from high-frequency training start to fade away if you can’t maintain that high of frequency long term? Luckily, the research seems to agree that frequency can be decreased significantly from a training program and fitness gains maintained over the long term[13, 15-17]. It seems that to prevent detraining, the intensity is the most important variable to maintain.
Part of the contribution of resistance training to muscular hypertrophy and strength is the expansion of the myonuclear domain of a muscle. The nucleus is one the main organelle in the muscle cell responsible for protein synthesis, however, one nucleus can only maintain a given area of muscle tissue. With strength training, cells known as satellite cells contribute their nuclei to muscles to allow for continued growth. Research has shown that following detraining, the myonuclear domain of a muscle remains unchanged. As Gundersen et al. put it, “The myonuclei seem to be protected from the highly apoptotic activity found in inactive muscle tissue.” They theorized that this is a contributing factor to what we refer to as “muscle memory” that allows for maintenance or quick return of strength and hypertrophy following detraining.
While all of this sounds great, there are several things to consider before beginning a high-frequency program.
- If your high-frequency training includes a lot of the same movements, there is the potential for overuse injuries. While this risk may be reduced due to a reduced daily training volume, it is still something to be considered with programming a high-frequency training program.
- While it may seem obvious, for such a program to work, the volume of work per day has to be reduced to allow for full recovery from day-to-day and to prevent injury.
- If you or an athlete you are training are relatively new to training, this type of training may not be for you as it seems to provide more of a benefit to trained individuals.
- While the proposed benefits are substantial, Dankel et al., pointed out that it is possible the body will accommodate to this type of training and stop producing the same magnitude of benefit over time. With that said, however, they suggest that since strength and hypertrophy can be maintained with reduced frequency following this type of training, that high-frequency training could be useful as a tool to be cycled to allow the body to become resensitized to a high-frequency training stimulus. This would make this type of training program very useful for breaking through plateaus or when significant increases in muscular hypertrophy are needed.
- Finally, it is important to remember that more research needs to be done on the subject to be definitive about its benefits. While research overall appears to show significant benefits for high-frequency training programs, there are still few volume and intensity controlled studies of high-frequency training programs on well-trained individuals. This is, however, an exciting area for researchers and coaches alike to discuss and explore further.
While there is more to learn about the subject, if you are a person who finds yourself with less time per day to devote to training, but still want to make strength and hypertrophy gains or if you have simply hit a plateau in your current training, a high-frequency training program might be a great way to change things up and spark new growth in your training program.
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