Sweet Spot Base I & II
The Sweet Spot Base training plans consist of Sweet Spot Base I & II, each with 3 different volume options; low, mid and high. Each begin with an assessment workout to establish training levels based on your incoming level of fitness.
Post-assessment, riders will face several specifically tailored weeks of training, each with specific workout types, interval types, efficiency drills, and intended physiological and psychological adaptations.
Nearly all of the Sweet Spot Base I workouts will be spent below FTP but this is not to say these workouts are easy. It is entirely possible to reach the point of muscular failure or high cardiorespiratory overload (or both) by targeting leg speed or force production capabilities only.
You can cook your muscles with nothing but force and you can cook them with nothing but speed, and while the aim is never intentionally to reach muscular failure at any time during either Sweet Spot base plan, Sweet Spot Base I & II will push you closer and closer to it in a variety of ways.
And to keep things a little more interesting, there's a couple over-under workouts sprinkled in to give riders a small taste of slightly supra-threshold effort.
During Sweet Spot Base I, overload will come in 3 forms: speed, force, & the combination of speed and force, or muscular endurance (ME).
The primary aim of ME conditioning is to increase sustainable-power producing capabilities. Improving this specific type of work capacity is a combination of strength and speed; strength being the amount of force one can exert over the pedals and speed being the rate at which you repeatedly exert that force.
In simpler terms, the goal is to increase the ability to turn big gears faster.
There are 3 ways riders can generate more speed on a bike: turn the pedals harder, turn them faster or do both at once. ME conditioning is exactly the latter, turning the pedals harder and faster at the same time.
In order to do this, it’s necessary to target leg strength/force production in addition to leg speed & muscle control, collectively referred to as "Form Work". One of each week’s workouts will consist mostly or solely of Form Work.
Speed & Force
Each week’s alternate workouts, i.e. Thursday intervals, usually; focus on applying an adequate amount of incrementally more demanding muscle endurance work. As such, the early-week workouts (Tuesdays, usually) are designed to very gradually improve leg speed, increase leg strength, and do both while complementing the improvements in muscular endurance targeted by the Sweet Spot intervals.
During these speed & force workouts, the focus shifts away from specific power levels and concentrates more on cadence, muscle control and raw strength.
While form workouts comprise a large part of Sweet Spot Base I, the ME aspect of the plan is consistently addressed as well by working at a couple different power levels, Sweet Spot and Threshold.
And in the interest of making the most of limited training time, speed and force drills are often woven into some of the Sweet Spot/Threshold workouts, increasingly so as the workouts trend away from form improvements and more obviously towards muscular endurance improvements.
FTP & VO2max Combined
During Sweet Spot Base I, power levels remain almost entirely between 2 subthreshold power levels, Sweet Spot (88-94% FTP) and Threshold (95-105% FTP).
Then, in Sweet Spot Base II riders will face a handful of shorter but far more intense aerobic capacity (VO2max) intervals rising as high as 130% FTP. But don't worry, you'll be ready for this sort of abuse when it arrives.
So while Sweet Spot Base I focused on improving muscular endurance in order to raise FTP, Sweet Spot Base II broadens its focus to also target improvements in higher-end power output which can further raise FTP.
FTP can only rise so high before a need to create more headway is required, almost as though you've pushed your FTP up against your current endurance ceiling. VO2max work can help you raise that ceiling in order to push your FTP even higher.
Another way to look at the relationship between FTP work and VO2max work is FTP demonstrates how well your engine runs but VO2max is more a measure of how big your engine is.
So build a bigger engine with VO2max intervals, then tune this bigger motor with Threshold intervals.
During Sweet Spot base, these VO2max intervals are just an introduction to this particular brand of suffering, but they'll become for more prevalent in the subsequent Specialized Plans depending on your specialty of choice.