How to Lose Muscle in 1 Week


It's my de-load week (funny timing for this article), and Sunday’s strength session still has me feeling more beat up than an open wound. Writing to you from behind a red light today so I'll highlight the skimmable version of my writing in RED today!

You might think it takes weeks, even months, to lose muscle. Turns out, it can start happening in just a few days.

If you’ve ever taken a short break from training and felt weaker coming back, it wasn’t just in your head.

After just 3 Days of inactivity → muscle loss begins

  • When muscles aren’t used, atrophy kicks in fast. Atrophy is the process of muscle loss.
  • Studies show just three days of immobilization (think: injury, bedrest, or not training at all) can lead to significant muscle loss.
  • A single strength workout can delay this… but only for a couple of days.
  • I've spoken about this before, but loading is KING for preventing muscle loss
  • Reference HERE

You can lose muscle within just 1 week

  • Muscle loss from detraining is slower than from complete immobilization, but it still happens within a week.
  • Recent studies confirm measurable losses in muscle size and fascicle length after just 7 days of no training.
  • If you train just once per week, you’re likely only breaking even.
  • References HERE and HERE

This means that

  • A few days off can lead to noticeable losses.
  • If you train once a week, you might not actually be progressing.
  • Training frequency matters more than most people think.

If you’ve been struggling with consistency, this is your reminder: the best training plan is the one you actually do—frequently enough to matter.

If you need help - we've got options like $20 Strength Club (3 days/week) or something more tailored like Custom Strength Programming. Got questions? Send them over! I reply 100% of the time.


ICYMI: We're opening up our 3rd ever workshop: The Conditioning Workshop to Calgary for September long this year. You won't want to miss it. We already have a few sign ups even though it's 7 months away.

Yours in physiology,

Carla

Physiology Toolkit

We're devoted to individualized training and rehabilitation, offering a detailed & measured approach to athletic performance. We've honed our expertise with elite competitors and Olympians in triathlon, bobsleigh, and track, and now bring the same methods to the everyday athlete eager to improve their health and minimize injuries. Access evidence-supported tips delivered through true tales, jaw-dropping examples, and clear exercise videos that make them easy to grasp and apply.

Read more from Physiology Toolkit
back pain

One of my clients has been with me for a few years now, and her story still blows me away. She had Harrington rods put in her spine as a child to treat scoliosis. Despite that, she had a long pro volleyball career, until chronic back pain forced her to retire. By the time we met, she was: In 4/10 pain on a good day, 8/10 on a bad one Having 2 flare-ups a week Relying on constant chiropractic care (weekly) Scaling back training intensity, frequency, and exercise selection to the point of...

Man is working out with weights at the gym.

This week’s newsletter dives into something that gets missed all the time in rehab: it’s not always about what exercise you do—it’s about how much it challenges you. I’ll walk you through a quick case study to show what I mean. Skimmable highlights in yellow below. “I’ve been doing all the exercises.” A client came to me last year frustrated that her pain hadn’t improved despite being incredibly consistent with her physio homework. She was now open to trying a trainer & hoping for a different...

HEY CALGARY (& surrounding area)... We've got a major announcement (if you haven't already heard). After touring to Florida in 2023 & Ottawa in 2024, it's time to stay home in 2025 & make this the best one yet..... .... what is it you ask? The Conditioning Workshop is landing in Calgary in 2025! September long (August 30th & 31st specifically) we will be hosting the most comprehensive conditioning and gait assessment workshop out there. Here's what others had to say about the workshop: "The...