The earbuds last for around five hours of use, with four additional full charges through the case – making for a sizeable 25 hours total on the go, more than you’d need for a full day’s use or a week’s worth of workouts. The primary earbud is both a receiver of data from your smartphone and a transmitter of said data to the secondary earbud.

If you’re leaving the case in a locker or rucksack during your workout, you’ll be fine, but be aware that the case isn’t anywhere near as compact as the earbuds themselves. Bass is strong without being overpowering, and you get a wide soundstage and a full range of 20Hz-22KHZ frequencies to boot. After all, Dwayne Johnson’s involvement is all over the box and is the main attraction for anyone after a pair of gym-ready headphones. You can’t really take it to the gym though, so something like the Bose Noise Canceling Headphones 700 might be preferable. There are very few differences between the JBL UA True Wireless FLASH X and the JBL UA True Wireless FLASH, save for the red accent ring on the first-generation earbuds.The problem with this stems from auditory masking tricking you into thinking you can’t hear something because the brain chiefly processes whatever sounds loudest. JBL continues its Under Armour collaboration with the new Sport Wireless Train on-ear gym-focused Bluetooth headphones.

The Project Rock Over-Ear Training Headphones holds on tight, but stays fairly comfortable for over an hour when worn with glasses. Brett Williams, a fitness editor at Men's Health, is a NASM-CPT certified trainer and former pro football player and tech reporter who splits his workout time between strength and conditioning training, martial arts, and running. You’ll appreciate having the IP rating on the UA Project Rock alongside the removable, and therefore washable, ear cushions. Under Armour (UA) and JBL provide a welcome amount of documentation with the Project Rock Over-Ear Training Headphones, including a wealth of instructions to walk you through its buttons and apps. The headsets share the same build and drivers, so sound quality and isolation are unchanged, but battery life has nearly doubled from the old to the new headset.The app describes the EQ as being able to deliver “premium sound quality with rich bass amplified to help you crush your workout”. The aesthetic of Project Rock lands somewhere between over-engineered and bonkers like a Tonka truck with its exaggerated proportions. If you're not interested in another pair of dainty buds you'll misplace in your gym back, this is the personal audio option for you. This allows you to carry on conversations with those around you, although it's weird to hear your voice enhanced as well.