TRAINING PRINCIPLES
Range of motion and muscle length
You'll often hear that the stretched position is where the growth happens. Here's how far the research actually supports that.
The short answer
Tailrep's programs default to the full range you can control on each lift. They aren't built on the premise that partials at long muscle lengths are superior.
What the research shows
- Varovic et al.'s (2025) meta-analysis reported comparable hypertrophy between training at longer and shorter mean muscle lengths.
- Regionally, there was a trend favoring longer lengths from the mid-belly toward the distal end. Most of that difference still fell within what the authors treat as practically equivalent.
- On top of that, the "long" and "short" conditions in the included studies differed by only about 21.8% of mean muscle length, which the authors flag as a reason for caution.
How to apply it
- Use the full range you can control on each exercise. That matters more than trimming range to add weight
- There isn't enough support right now to rebuild a program around the idea that stretch-position work is special
- If you change the range, log it as a separate exercise. Keeping the same name while changing the range makes the trend line meaningless
Programs built on this principle
References
Limits of this evidence, Regional hypertrophy is an active area of research. This page may need rewriting as results come in.
Varovic D, et al. (2025) International Journal of Sports Medicine
Does Muscle Length Influence Regional Hypertrophy? A Systematic Review and Meta-Analysis
Krause Neto W, et al. (2025) Frontiers in Physiology
The impact of resistance training on gluteus maximus hypertrophy: a systematic review and meta-analysis