Turbo training is a bike session that involves cycling indoors on a turbo trainer/static bike device with your bike positioned onto it.
A turbo trainer is an indoor cycling trainer that either clamps your rear wheel into the unit or has its own cassette that you fit your chainset onto with the rear wheel removed (known as a ‘direct drive’ turbo turbo).
The benefits of turbo training are the safe environment (shed, garage, utility room or garden) they are conducted in compared to cycling on the road. They have a year-round benefit, especially in the autumn and winter months when riding in the dark, wet, ice and cold isn’t as appealing or safe as daylight riding in the summer months.
Turbo training will also give you a structured session where you can control the intensity and the resistance offered by the unit (which can be controlled by fluid, air or magnetic forces) instead of relying on a road route to do this.
The downsides of turbo training are they won’t improve your bike handling/cornering technique, ability to ride in the wind and rain, and ascending and descending skills on the bike in the same manner as road riding
For triathletes, using a triathlon-specific bike or road bike with clip-on aerobars on the turbo trainer can also prepare your body for riding extended periods in the aero position and will allow you to tweak and reset your position.
Where turbo training used to be mind-numbingly boring, the advent of Smart Trainers (see units from the likes of Bkool, Wahoo and Tacx) and virtual reality packages such as Zwift, Sufferfest and TrainerRoad have created a world of interactive and entertaining riding.