Mental stress decreases strength gains?

Can mental stress negatively influence strength gains?

Mental stress can have many negative physiological effects on the body, such as an increased risk on cardiovascular disease. Mental stress has also shown to negatively impact acute athletic performance. But does it also have a negative effect during a training program?

This study investigated if mental stress affects strength gains during 12 weeks of resistance training. The subjects were college students participating in a university weight training class (n=135). The subjects were divided into a high or low stress group based on questionnaires. Strength was assessed with 1 rep max (1RM) tests for the bench press and squat.

As expected, both groups increased their bench press and squat 1RM during the training program. However, the increase in bench press strength was larger in the low vs high stress group (+15 vs 12%, respectively). Likewise, the increase in squat strength was larger in the low vs high stress group (+27% vs + 23%). 

Limitations of the study include that the training program was not strictly supervised, and that stress was only assessed by questionnaires.

The data suggest that mental stress is a factor that may modulate your progress in the gym.

Study:
Bartholomew et al. Strength Gains After Resistance Training: The Effect of Stressful, Negative Life Events. J Strength Con Res, 2008.

Go to the next study in the stress series:
Quality time with partner reduces cardiovascular stress?