If your training load is reduced for only 2 months, you can lose up to 12% of your muscle strength! Read on to find out more.
If you happen to be flicking through the opening pages of a sports science textbook, you’re likely to stumble upon a list of fundamental training principles. These principles form the foundations on which strength and conditioning training is built. One of these is the principle of reversibility, which means that all positive effects of physical activity, including gains in muscular strength and aerobic fitness, are reversible. In other words, use it or lose it! If an athlete’s training load is reduced, or they stop training altogether, then they are likely to lose the gains that they have worked so diligently to achieve. This, in turn, leads to reduced performance in competition and a higher risk of injury.
When an athlete takes part in training, they provide their body with stimulus to promote change. Whether it’s an increase in the strength of their muscles, the aerobic capacity of their heart and blood vessels, or something else, this change is designed to improve sports performance. The opposite of training is, quite simply, “detraining” - the temporary or permanent withdrawal of stimulus. Evidence has shown that periods of detraining following strength and conditioning training can lead to significant decreases in training-induced adaptations. It begs the question, how long before gains are lost? And how quickly do they disappear?
Before getting into the research, it’s important to consider that strength and conditioning training can induce a whole host of physiological adaptations. There are changes in muscle strength, hypertrophy, power and endurance, neural drive to muscle, aerobic fitness and plenty more. You can then break down strength gains into concentric, eccentric and isometric strength, or even measure muscle activation or the percentages of different muscle fibre types. For now, let’s focus on muscle strength and aerobic fitness, perhaps the two most important components in any athlete’s performance.
So, what does the evidence say about the effects that a period of reduce training volume, or no training at all, has on muscle strength and aerobic fitness?
Interestingly, your body can maintain its muscle strength for almost a month with minimal training (2,3). However, after only 2 weeks, your eccentric force and sport specific power decline (3). This will affect your ability to land smoothly, absorb force and explode into a sprint. By 8-12 weeks, you lose around 7-12% of muscle strength (1). This is due to neural alterations, firstly, and then changes in muscle morphology (1). After 8 months, you will have lost almost a quarter of your muscle strength (1).
Let’s put this into practice. Imagine you’ve been working on your back squat, and when you test your 3-RM on New Year’s Day, you lift 100kg. If you stop training, your result is likely to drop to around 95kg by February, and 90kg by early March. By September, it’s down to 75kg! Remember, it probably took you 12-18 months (or more) to increase your 3-RM from 75kg to 100kg, so by September, it’s back to square one and those 12-18 months of training will feel like a waste.
The same goes for aerobic fitness, but we tend to lose this even faster. After 2 weeks of detraining, measures of aerobic fitness like VO2max and exercise time to exhaustion are reduced by 3-4% (4). After a month, they drop by 4-17% and the fitter you are, the larger the drop (5,6)! Whilst this may not directly relate to endurance performance, studies have also observed reduced performance with short- and long-term detraining periods (1). With a faster decline in aerobic fitness, though, comes the ability for trained athletes to regain it more quickly than muscle strength (1).
If that all sounds a little confusing, here’s a rough timeline for the effects of detraining:
2 weeks = sports performance declines, aerobic fitness down 3-4%
4 weeks = muscle strength declines, aerobic fitness down 4-17%
8-12 weeks = muscle strength down 7-12%
32 weeks = muscle strength down 25%
Fortunately, it’s not all doom and gloom. Let’s talk about how you can avoid the effects of detraining by maintaining your fitness levels. After all, most athletes experience periods of detraining at some stage, whether it be through injury, over the off-season, or even when taking a break from sport. Some of you may even be thinking, “If I’ll only lose 10% of my muscle strength, then why don’t I have a month off?!” Well, let me pose another question: what if you can maintain or even improve that muscle strength with only 1 session per week, and it will help your performance in the long run?
As it turns out, the evidence suggests this is true. Studies show that you can reduce your training load by almost 90% and maintain muscle strength for up to 8 months (7). With a reduction of 66%, you can not only maintain your strength, but continue to improve it in small amounts (7). This means that if you’ve been training three times per week, completing three sets of bench presses per session, then you can reduce this to 1 weekly set and maintain your bench press 1-RM, or to 3 weekly sets and continue to get stronger. Sounds like a pretty good deal to me.
Meanwhile, aerobic fitness can be maintained for almost 4 months with only 33-66% of the original training volume (7). This equates to one or two weekly runs instead of three. Experts also say that minimising the aerobic effects of detraining is associated with better endurance performance the following season (7).
However, the key ingredient in both cases is that intensity must remain the same. If you’ve been lifting 75% of your 1-RM in 3 weekly sessions, and you’re looking to cut back to 1 weekly session during the off-season, continue to lift at 75% of your 1-RM. This will mean doing regular testing throughout the off-season to ensure you are lifting the appropriate weight, as your 1-RM or 3-RM may continue to improve. After all, the most important principle of resistance training is progressive overload, whereby the muscles must be regularly challenged by unfamiliar stimulus, or heavier weights, to achieve continued strength gains. Likewise, if your target heart rate range for aerobic training has been 160-180bpm, you should continue to hit this range with your reduced training volume. If intensity is not maintained, studies suggest that your muscular and aerobic fitness levels tend to drop.
In summary, it’s important to remember that all of the benefits you reap from training are reversible. It’s a case of use it or lose it. If you don’t use it, you will quickly notice a drop in sports performance. After a month, your muscle strength declines, and your aerobic fitness will have dropped substantially. After several months, you will have lost an immense amount of muscle strength. These outcomes hinder performance at training and in competition, whilst increasing injury risk, making for one very unhappy athlete.
Fortunately, you can continue training with a reduced volume at the same intensity and avoid this scenario. This could mean smashing out 1 run or sweat session and 1 weights session per week, or even 1 set of weights if you’re really short on time. This will allow you to maintain those gains in muscle strength and aerobic fitness that you have grinded so hard all year to achieve, and even improve your performance when you return to competition, rather than throwing away months or years of work. All in all, if you’re taking a break from sport, approaching the off-season, or recovering from injury, don’t leave training off your to-do list! Keeping your body strong and fit is simple and achievable, and your future athlete self will thank you for it.
Author: Mac Herring
Strength & Conditioning Coach
Clinical Exercise Physiology
Resistance Sports Science
References
Girardi, M., Casolo, A., Nuccio, S., Gattoni, C., & Capelli, C. (2020). Detraining effects prevention: A new rising challenge for athletes. Frontiers in Physiology, 11. https://doi.org/10.3389/fphys.2020.588784
Encarnação, I. G., Viana, R. B., Soares, S. R., Freitas, E. D., De Lira, C. A., & Ferreira-Junior, J. B. (2022). Effects of detraining on muscle strength and hypertrophy induced by resistance training: A systematic review. Muscles, 1(1), 1-15. https://doi.org/10.3390/muscles1010001
MUJIKA, I., & PADILLA, S. (2001). Muscular characteristics of detraining in humans. Medicine and Science in Sports and Exercise, 33(8), 1297-1303. https://doi.org/10.1097/00005768-200108000-00009
Chen, Y., Hsieh, Y., Ho, J., Lin, T., & Lin, J. (2021). Two weeks of detraining reduces cardiopulmonary function and muscular fitness in endurance athletes. European Journal of Sport Science, 1-8. https://doi.org/10.1080/17461391.2021.1880647
Mujika, I., & Padilla, S. (2000). Detraining: Loss of training-induced physiological and performance adaptations. Part I. Sports Medicine, 30(2), 79-87. https://doi.org/10.2165/00007256-200030020-00002
Joo, C. H. (2018). The effects of short term detraining and retraining on physical fitness in elite soccer players. PLOS ONE, 13(5), e0196212. https://doi.org/10.1371/journal.pone.0196212
Spiering, B. A., Mujika, I., Sharp, M. A., & Foulis, S. A. (2021). Maintaining physical performance: The minimal dose of exercise needed to preserve endurance and strength over time. Journal of Strength and Conditioning Research, 35(5), 1449-1458. https://doi.org/10.1519/jsc.0000000000003964