While being perfectly user-friendly, curved treadmills are indeed harder to use, as they require you to work harder. This is because keeping the belt moving provides an extra challenge to your core and leg muscles, leading to a higher energy expenditure. On top of this, some curved treadmills come with adjustable resistance for an extra level of control over your workout. This is compounded by the 15-degree curve, which challenges your whole body and burns up to 30% more calories. The curve also improves running form, designed to mimic your natural stride pattern and increase posterior muscle activation, which can help in rehabilitation.
So while a FreeRun treadmill may be technically harder to use in the sense that they require greater muscle activation, this difficulty is built-in to accelerate returns on your exercise and deliver greater results.
Having said this, many users find that the curved treadmill allows for a smoother and user-friendly experience, as it allows you to control the speed and intensity of your workout at all times. The ability to set your own speed as you go means you have greater control over your workout, and allows for more complex exercise routines involving variations in intensity. This also makes them great for High Intensity Interval Training (HIIT), giving the user the ability to accelerate intensity quickly without having to stop to change any settings.
For a more comprehensive breakdown of the difference between motorised vs curved treadmills, click here