Generally speaking, the fitter you are, the bigger the drop in size, strength, and performance when you take too much time off from training. Why? Because it takes a huge amount of energy for the body to be extremely fit. Any chance it gets, the body will begin reducing its high-performance build to save energy.
Strength athletes seem to have an advantage over endurance athletes, as cardiovascular conditioning is lost more rapidly than strength and the ability to produce power.
A Concrete Example
In the table below, you can see the changes that occurred to an elite powerlifter when he stopped training for 7 months.
The powerlifter reduced his weight dramatically. This was due to a massive drop in body fat, but also a huge decline in muscle mass. His type II fibers shrunk in cross sectional area.
How Fast Do You Lose Strength?
The degree of strength you’ll lose during time off will vary depending on your genetics, age, training experience, what muscle groups we’re talking about, how much time you take off, and whether it’s a complete break (no training) or a partial break (reduced training).
You’ll certainly lose more strength the more time you take off. But taking off a week or two does not seem to matter much in the bigger picture.
Here’s what else the studies show:
- One study done by Hortobagyi et al., showed strength to be preserved even after two weeks off in strength athletes.
- Scientists found strength to be preserved for up to four weeks. There’s also research showing that if you refrain from taking a full-on break, hitting the gym occasionally for some short sessions, you can even get away with six weeks “off” without losing significant strength.
- In studies done on untrained participants, there was a rise in strength of 31% after four weeks of training. They followed that up with two weeks without training, and their strength had only dropped by 5%, with 24% of their strength gains still remaining.
- In Olympic weightlifters, drops of 10% in squat strength has been observed after four weeks without training.
- In a study by Lemmer et al., strength increased after nine weeks of training in a group of 20-30 year olds (34% increase) and a group of 65-75 year olds (28% increase). After a 31 week break, strength dropped 14% in the young group and 8% in the older group. No matter the age, strength gains dropped mildly the first 12 weeks of non-training, whereas the biggest drop was observed in weeks 13-31.
- In young people who are still growing, breaks seem less catastrophic because these individuals will become “naturally” stronger as a result of the general maturation process, including increases in testosterone levels. Older people, on the other hand, lose strength faster than younger people when they stop exercising, especially if the break is long. In a study on 68 year-olds, six weeks without training resulted in a 15% drop in strength.
How Fast Do You Lose Size?
Since there’s a correlation between strength and muscle fiber size, there will in most cases be a drop in mass alongside strength. However, it’s believed that the loss of strength observed in the first weeks of non-training is primarily associated with a decreased neural drive – a weakening of the firing system of the nervous system, while a loss of muscle fiber size takes a bit longer.
Some studies have shown an onset of muscle atrophy as soon as two weeks after cessation of training. Other studies have shown that there’s no atrophy after such a short period of time. As with strength, the degree of atrophy is probably closely related to how active you are during your break, and how fit you are when you go on a break.
This is worth repeating: more mass is associated with more pronounced atrophy. And the older you are, the more aggressive the atrophy seems to be. This might be related to the fact that younger people are generally more physically active than older individuals, and inactivity is one of the most important factors for the onset of atrophy.
In one study, participants increased the CSA (cross-sectional area of muscle fibers) in their quads by 10% after three months of training. But three months without training later, and all of these gains were completely gone.
In another study, participants experienced an increase in CSA of 26% and an increase in strength of up to 40% after participation in a 24-week strength training program. After 12 weeks without training, CSA dropped to baseline levels, but in same period of time, strength only decreased by 30%.
This indicates that the neural adaptations had not completely disappeared even though the atrophy was pretty aggressive. Under normal circumstances hypertrophy is more pronounced in type II muscle fibers when you engage in a strength training program, and it’s also believed that type II muscle fibers atrophy more willingly than type I fibers.