Don't Worry! You won't lose your gains by taking a week off.

One of the biggest worries voiced by my clients is the fear of losing their gains when taking some time off, whether it be for vacation or due to injury. Let me give you some ease of mind when I relay what the research suggests; Younger adults can probably “get away with” about a month of training cessation before losing too much strength and muscle mass. Older adults (>60-65) may be able to get away with about two weeks of training cessation. After that, losses accelerate. 

When you lose muscle mass due to a period of inactivity or detraining, it is generally easier to regain that muscle compared to building it from scratch. This phenomenon is often referred to as muscle memory. The retraining period (the amount of time it takes to regain lost muscle and strength) following a period of training cessation seems to be about half as long as the period of training cessation. So, if you’re out of the gym for 12 weeks, you should be able to regain the vast majority of your lost strength and muscle mass in approximately 6 weeks.

There are a few reasons why it is easier to regain lost muscle mass:

1. Muscle nuclei retention: During periods of muscle growth or hypertrophy, the muscle fibers incorporate additional nuclei. These nuclei play a crucial role in protein synthesis and muscle maintenance. Even if muscle mass decreases due to inactivity, the nuclei that were gained during previous training remain in the muscle fibers. When you resume training, these existing nuclei can facilitate protein synthesis and accelerate the muscle rebuilding process.
2. Enhanced neuromuscular connections: Through previous training, your nervous system has learned how to efficiently recruit and activate the specific muscle fibers involved in a particular movement or exercise. This neural adaptation is not lost even if muscle size decreases. When you start training again, the neural pathways responsible for coordinating muscle contractions are already established, allowing for more efficient and coordinated muscle activation.
3. Muscle fiber hypertrophy potential: Research suggests that muscle fibers that have previously undergone hypertrophy have a greater potential for regrowth. These muscle fibers have already stretched and expanded during previous training, making it easier for them to regain size and strength compared to muscle fibers that have never experienced significant growth.
4. Cellular adaptations: When you train and build muscle, there are various cellular adaptations that occur within the muscle fibers, such as an increase in the number of myofibrils (contractile units) and improvements in mitochondrial density (energy production centers). Even if muscle mass decreases, these cellular adaptations persist, which can facilitate a faster regain of muscle size and function.

It is important to note that while regaining muscle mass may be relatively easier after a period of detraining, it still requires consistent and progressive training along with proper nutrition to stimulate muscle growth. The rate at which muscle is regained may vary depending on factors such as training intensity, duration of detraining, and individual genetic factors. 

If you have the time, ability, and inclination to do any training while stepping away from the gym, you can significantly mitigate the losses in strength and muscle mass you’d otherwise experience during a period of total training cessation.