"Whether it be a phone, a water bottle, a set of keys, a towel, or a shirt, running with something in one hand while running can cause you to use your body differently than if you were running with nothing," explains Men's Health Fitness Director Todd Liubinskas.
These days smartphones don’t weigh much (a couple of hundred grams on average). But even tiny imbalances in the distribution of weight can cause major problems with alignment.
"When you are running, the aim is to keep consistent cadence. Equal distribution of weight and momentum allows for a smoother run," Todd explains. "Now, once we place something into our hands, that causes an effect of asymmetry within the running style you are used to."
The main issue here is the repetition of movement. By making one arm heavier and swinging it back and forth thousands of times, your body will work certain muscles harder than others to compensate. This makes you way more susceptible to strains, particularly in your legs, hips and shoulders –usually on the opposite side of the body to the one you hold your phone on.
"Pending on how far you are running, leave your phone in the car, and get the selfie at the start and at the end," Todd recommends. "My advice would be do take some mates running with you, and have a chat to each other, rather than be on your phones, the memories will last longer, and the run will be more enjoyable."
Another option? Invest in a bum bag to stash all your stuff.