Does being on your mobile phone before training actually cost you gains or was that old strength coach yelling at you for nothing?

Overview

What did they test? The researchers looked at how 30 minutes of smartphone exposure affected various training outcomes before a lifting session.
What did they find? 30 minutes of social media browsing resulted in less training volume performed and more perceived mental fatigue versus the control group of the study.
What does it mean for you? Although more research is needed, it is probably best to avoid prolonged exposure to your smartphone before training if you want to absolutely maximize your performance.

What’s the Problem?

As you’re probably well aware by now, making muscle and strength gains is relatively straightforward, especially when maximizing adaptations is not of interest. However, fine-tuning variables such as sets, intensity, and rest time can ensure you get the absolute most out of your sessions. 

Navigating the nuances of lifting weights entails addressing challenges, and one significant roadblock is cumulative fatigue. This fatigue creeps in as the number of reps increases across consecutive sets when lifting, with previous studies focusing mostly on the mechanical side of things, looking into factors like muscle bioenergetics and force generation 1. However, an intriguing avenue yet to be fully explored is the impact of mental fatigue particularly on resistance exercises.

Defined as a psychobiological state characterized by tiredness and diminished energy following mentally demanding tasks, mental fatigue has been extensively studied in the realm of whole-body endurance exercises 2 but not so much in the context of lifting weights. Although not entirely clear just yet, some of the proposed mechanisms for mental fatigue involve intricate processes within the brain's prefrontal cortex, especially the anterior cingulate cortex. The prefrontal cortex plays a pivotal role in executive functions such as decision-making during exercise, allocation of attention focus, and processing environmental information. Despite these insights from whole-body endurance studies, the impact of mental fatigue on lifting performance remains a relatively uncharted territory. Despite not having received a ton of attention, it may be that the role of mental fatigue in lifting is somewhat understated, especially given the current data on the effect of mental fatigue on endurance training performance.

Now, you may be wondering how all this is relevant to you and your goals. Well, it turns out that smartphone usage, especially social networking apps, has been linked to cognitive function and performance impairment 3. You’ve probably seen the odd meme or video making fun of people taking way too long between their sets because they’re distracted on their phone. But aside from delaying you from using the gym equipment, could these people be missing out on gains? And if you’re someone who often spends a significant amount of time on your phone before your session, could that be hindering your progress by increasing your mental fatigue?