There’s good news and bad news in a remarkable new multi-year study of nearly 15,000 people who followed an ultra-minimalist strength training plan with just one short workout per week. The good news is that the workout really works, even though it takes less than 20 minutes a week in street clothes. The bad news is that at some point it stops working, or at least becomes less effective – a phenomenon that researchers claim is universal rather than specific to the training plan, and that has important implications for how we think about long-term training goals.
The study is being preprinted to SportRxiv, which means it has not yet been peer-reviewed (although it is currently going through this process). It retrospectively analyzed data from a Dutch personal training company called Fit20, whose motto (according to Google’s translation of its Twitter bio) is: “Personal health training in 20 minutes a week … no hassle with changing / showering”. The model was franchised in other countries, including the United States, with locations in Florida, Virginia, Utah, and Michigan.
The training plan includes one workout per week, typically six exercises on Nautilus One machines: chest press, pulldown, leg press, abdominal flexion, back extension, and either hip adduction or abduction. For each exercise, do a set of a weight chosen so that after four to six repetitions you get a temporary mistake. The repetitions are done slowly, lasting ten seconds up and ten seconds down without locking the limbs or resting up or down in the movement. The break between exercises is usually around 20 seconds. The loads are adjusted from session to session so you don’t fail after four to six reps. There is no music and no mirrors.
The trainer records your loads on a tablet at each session and uploads them to a cloud-based database. This in turn provides a gold mine of anonymized data for strength training researchers. The team that analyzed the data was led by James Steele, an exercise scientist at Solent University and the UKActive Research Institute. He and his colleague searched the records of 14,690 Fit20 customers who had trained with this system for up to 6.8 years. It is not a randomized study, but the large numbers and long follow-up time, as well as the highly standardized training program, make it an extremely unusual data set.
There is really only one outcome variable of interest: How much stronger did the subjects get over time? The paper analyzes the training load for leg press, chest press, and pulldowns. All of them produce pretty much the same pattern: quick wins for about a year, then gradual wins after that. Here is a representative graph showing the chest press exercise load over a period of nearly seven years as a percentage of the initial load:
After a year, the typical topic has become 30 percent stronger. After seven years you are up about 50 percent. They keep winning, but the margins are getting smaller. The patterns are similar for the other exercises, although the numbers are slightly different. For example, the leg press is about 70 percent higher than the baseline.
There are several ways to slice and dice the data, most obviously keeping in mind the effects of age and gender. The subjects had an average age of 47 years but spanned a broad spectrum with a standard deviation of 12 years; 60 percent of them were female. None of this seemed to make a difference. Younger subjects tended to be stronger initially, as were men, but the rate of progress and the plateau after one year were consistent across groups.
From a public health perspective, the takeaway seems clear here: a “minimum effective dose” approach to strength training really works. Once you reach adulthood, you typically lose about one percent of your strength each year, with a steeper decline in your 60s and beyond. Even the plateauing phase of this data, when subjects experience modest gains in strength, represents a significant bend in the age curve. If you follow a program like this – or a program that makes similar slow but steady progress – you win. You don’t need to feel guilty for not building up a large volume of exercise, following elaborate periodization schedules, promoting muscle confusion, or whatever is currently in vogue.
From a performance standpoint, the takeaways are a bit gritty. Does the plateau with this training plan suggest that a similar plateau will occur with all of the strength training plans? This is a risky generalization, but Steele and colleagues point to several other references in the literature that suggest this is common. With data from powerlifting competitions, for example, progress also appears to flatten out after about a year, although powerlifters are likely to follow much more sophisticated and rigorous periodic training schedules.
One possibility is that all programs will ultimately lead to declining returns and the solution is to add a new or different stimulus. Surely it is likely that if you plateau in one program and then move on to another, you will see rapid progress in the specific moves and challenges of the new routine. However, it’s less clear whether this advancement is task-specific or whether you are actually regaining generalizable strength quickly.
Asking whether this minimalist approach is really enough to optimize strength gains reminds me of the epidemiological data that suggests you can get most of the benefits of running in just five minutes a day. This does not correspond to the experience of competitive runners who do not “mostly” become able to run five minutes a day. The key is to remember that the minimum dose for health and the optimal dose for performance are two separate questions. Fit20’s new data offers some fascinating insight into the former question, but shouldn’t be confused with the latter.
If you’d like to learn more about Sweat Science, visit me on Twitter and Facebook, subscribe to the email newsletter, and read my book Endure: Mind, Body, and the Strangely Elastic Limits of Human Achievement.
Main photo: David Prado / Stocksy