Lean Muscle Mass Improvements are Better with Trainer Assisted Workouts

Jefit App
3 min readMar 30, 2022


Do you think someone can build more muscle training alone at a gym or with a personal trainer pushing them? A group of researchers wanted to know the answer to this question. They ended up going the scientific route. They put together their own study to find out the best way to build muscle mass.

What the Research Showed

The study, published in the Journal of Strength and Conditioning Research, looked at the effect of supervised workouts on building lean muscle mass. The researchers hypothesized that “club members randomized to receive an evidence-based training program would accrue greater improvements in lean body mass (LBM) and other fitness measures than members randomized to self-training”. The subjects were all men between the ages of 30–44 years old who were members of a club in Southern California. Both groups (n=17) trained 3x/week for a period of 12-weeks.

Supervised Workout Improvements

The supervised group saw a significant increase in LBM of 1.3 kg (2.86 pounds) following 12-weeks of training while the self-trained group saw no change at all. The trained group also saw a 2 percent decrease in body fat while the self-trained saw only a 1 percent change. The trained group also experienced an increase in 1-RM in chest press (42 percent) and leg press (35 percent). The self-trained group saw increases of 19 and 23 percent respectively. In terms of aerobic capacity (VO2 max), there was a 7 percent increase in maximal oxygen uptake for the trained group. There was a 3 percent decrease for the self-trained group. Dietary intake was not controlled for in this study.

Some individuals are able to train well on their own and make great gains when it comes to strength and muscle mass. This one study showed that results can be even greater when you have someone pushing you. Keep in mind their were a few study limitations. This study was completed using only young, male subjects and the sample size was small. Even so, you may want to look into getting a workout partner?


Storer TW, Dolezal BA et al., (2014). Effect of Supervised, Periodized Exercise Training vs. Self-Directed Training on Lean Body Mass and Other Fitness Variables in Health Club Members, J. Strength and Conditioning Research, 28(7):1995–2006.

Use Jefit App to Help You Build & Track Muscle Mass

Jefit, named best strength training app for 2022 by MUO, BYRDIE and ORIGYM, has a community that’s responsible for 92,000,000 workouts to date! The app, which recently passed 10 million downloads, comes equipped with a customizable workout planner and training log. The app has ability to track data, offer audio coaching cues, and can share workouts with friends. Take advantage of Jefit’s exercise database for your strength workouts. Visit our members-only Facebook group. Connect with like-minded people, share tips, and advice to help get closer to reaching your fitness goals. Stay strong with Jefit.

Originally published at https://www.jefit.com on March 30, 2022.



Jefit App

A mobile fitness app for Android & iOS devices that manages & tracks your workout. More than 10 million downloads. Michael Wood, CSCS, is the Content Manager.