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The S:6 Off-Season Base Builder Cycling Plan (a Deep Dive!)

The S:6 Off-Season Base Builder Cycling Plan (a deep dive!)

Post Series: Off-Season Program

The stationary trainer is one of the best tools in your training arsenal.

The highly controllable environment makes it one of the most effective ways to improve your cycling power. By allowing your workouts to be controlled using variables like time, gearing, cadence, power and heart rate you can more easily execute precise, repeatable intervals. On the trainer you can eliminate the uncontrollable variables found in outdoor workouts like varying terrain, wind, weather, traffic, etc. You can focus solely on the work you are performing to make the most out of the time you are putting into your training.

Our 24 Week Base Builder Program/Plan, as well as its condensed little brother: the 12 Week Base Builder Program/Plan, are both designed to be performed during your “off-season”. The term off-season is referring to time off from racing, as opposed to time off from training. This concept is explained in a previous post, Ideas for Your Off-Season.  During this off-season base-building phase your primary objectives are to develop a strong aerobic system and build sport-specific strength.

Training Blocks

Our 24-week Base Builder program is built around six 3-week training blocks. Each block has a specific training focus that builds upon the previous block in intensity and training load. Within each block there are three weeks of loading (training) followed by one week of recovery (low-intensity), before getting into the next block. Each training block targets a specific energy system and the overall progression is from lowest intensity to highest intensity before reaching a peak at the end of your base build.

The energy system block progression on the trainer includes the following:

  • Block 1: Pedaling Skills/Aerobic Intervals
  • Block 2: Aerobic Threshold/Aerobic Strength 
  • Block 3: Anaerobic Threshold (including FTP)
  • Block 4: Vo2 Max
  • Block 5: Anaerobic Power 
  • Block 6: Peak Power 
In our off-season Base Build Program we leave zone 1/2 aerobic endurance training to longer outdoor rides and/or other extended aerobic endurance building activities such as skiing, hiking, running, etc. as time and weather permits.

The primary difference between our two programs, 24 vs. 12 weeks, is that speed at which the progressions through energy systems occur. The 24-week program allows for a more thorough off-season build and deeper base development for those that have the time and/or interest. While our condensed 12-week program goes through all six of the same energy systems as the longer version, it does it at much faster rate allowing for fewer weeks of training for those that don’t have the time due to an extended previous season of racing (or period of inactivity or training) or an earlier upcoming season of racing.

Upon completion of our 24-week or 12 week Base Builder programs, you will be ready to transition into your Race Season and/or more specific Race Preparation training phase.

This is when your training become more specific to address the demands of your goal race(s): road cycling, XCO mountain bike racing, endurance mountain bike racing, triathlon of all varieties and durations, etc. But before you can bring your race fitness to a peak, you must establish your base.

As a general rule of thumb, the longer, bigger, deeper more thorough base of fitness you can develop each year, as well as over many years, the more demands you can apply on yourself in your race preparation training and on race day. Most everyone is aware of this concept; however it is surprising how few racers actually apply it. Many racers hinder both their development and performance by not doing the specific training required in the off-season to build a prober base from which top-end fitness can be achieved.

 Training Zones & Testing

Our Base Builder programs/plans uses two primary metrics for training progression; one for measuring actual workload (power) and the other for measuring your body’s response to the workload (heart rate). You’ll ideally want to be equipped with both metrics to make the most of the training series (ie. power-meter and/or smart trainer AND heart rate monitor). To use one without the other shines light on only half of what’s really going on! Learn more about training with BOTH power and HR in a previous post: Training with Power or Heartrate? 

Within the 24-week program you will perform 4 tests; the first to establish your starting fitness and training zones, and 3 re-tests (one every 8 weeks) to track progress and adjust zones as you increase fitness. Within the 12-week program you test in week 8, but can opt to perform an earlier test in week 4 if you feel improvements have been made.

Our Testing protocol differs from many of the popular methods you may be familiar with. Our S:6 Testing Protocol includes a 20-minute sub-maximal Aerobic Threshold Test, to identify your Aerobic Power and track aerobic development; while three short maximal test efforts identify your Anaerobic Power, to determine your rate of fatigue as durations increase to used to calculate your extended training zones. With these data points we can more accurately calculate your training zones and better track improvements in fitness.

With your test completed, you will enter your result data into our S:6 Training Zone Calculator (Excel Spreadsheet) to receive your personalized Power & Heart Rate training zones pertaining to each energy system to be trained.

  • Aerobic Threshold HR (AeT HR)
  • Anaerobic Threshold HR (AnT HR)
  • Fatigue Rate
  • Your Individual Power & HR training zones
  • Functional Threshold Power (FTP) 

From here you simply enter your FTP number into your Training Peaks account to have your individual training sessions adjusted specifically to you. If using a Smart Trainer, you then can download the workout files to match your device and the power loads will be adjusted specifically to you as well. All super slick and takes the guess work out of everything, and you know every session is dialed in specifically to your current fitness.

Training with Power & HR

Training with power is one of the best things to happen to indoor training since the trainer itself. With power you can target specific workloads in a highly repeatable fashion and relate the workload to how your body responds to it via heart rate to track progress and performance. Today power-meters and power based “smart trainers” have become more affordable, easier to use and are widely available to any serious cyclist looking to improve their performance. This training series is designed around power to make it individualized to each user.

There are two heart rates that will be referred to in the workout series, and you will want to figure your specific HR’s out and memorize them.

The first is your maximum aerobic heart rate or aerobic threshold (AeT). The primary objective when building aerobic endurance is to improve your ability to burn fat for fuel while sparing glycogen (stored carbohydrates). The higher percentage of fat-to-carb you can train on, the faster and longer you will be able to go on race day as you will be relying less on sugar for fuel, which will increase your maximum sustainable power cycling. By training at (and a range of 10 beats below) your aerobic threshold (AeT) you’re training at your highest output while burning predominantly fat and keeping sugar-burning to a minimum. As you become more fit at this pace you will be able to train longer and longer distances on less and less energy (or go the same distance faster!).

The second heart rate that is referred to is your Anaerobic Threshold Heart Rate or AnT HR. This is your 1-hour race-pace heart rate. The balance point between lactic acid being metabolized for energy and accumulating in your blood. Train at or just below this effort level and you can increase your race-pace at any distance; go above this threshold for an extended period of time and you risk damaging your hard-earned aerobic development and will require significantly more recovery time between training sessions. You will likely spend more time training in this zone in your race specific  preparation following your base training, but you will hit this zone in small amounts in this series of workouts to prepare the body for the more extensive AnT training throughout your racing season.

The relationship between power and heart rate is super key in identifying training adaptations and knowing when to make progressions.

Power measures the output of work you are doing. Heart rate measures the response your body has to the work that is being done. When you can do the same work (power) with a lower response (lower HR), you know you are adapting to the work and making fitness gains. If you are doing the same amount of work (power), but working harder to do it (higher HR), then you have a problem that needs to be addressed by slowing down or resting. By using both metrics in your training you can make better decisions on when to increase workloads and when to back off.

Trainer Session Layout

There are several specific exercises that will be utilized throughout the workout series. Each workout is intended to last roughly 75 minutes in duration. With the duration static, the workouts are designed to progress with a higher and higher workload with each successive workout. The basic layout of every workout includes a warm-up to gradually elevate the HR (appx. 15-20 minutes), two to three exercises make up the main-set of the workout (appx. 45-50 minutes), and a cool-down spin to bring the HR back into normal resting ranges (appx. 5-10 minutes). Each exercise has a specific duration, cadence, gearing, HR and power guideline to follow.

The Exercises

There are nine exercises utilized within the workout series. Each one has a very specific protocol to following including variables such as resistance/gearing, cadence, power, HR, work duration and recovery duration. Below you will find a description of each exercise.


Used in this application as both a warm-up exercise and leg-speed development. These should be performed in your easiest gear with very little resistance. Your cadence will increase per instruction, your HR will rise gradually along with your cadence. HR is to not exceed your AeT HR. If your HR gets too high, lighten the resistance on your trainer or cease cadence increase until you improve your economy over the next several sessions.

Isolated Leg Training (ILT):

This exercise is both a leg strengthener and pedaling efficiency improver. You will unclip one leg and rest it on the back of your trainer (or let it dangle), while pedaling with the other leg. Complete the interval, clip the resting leg back in, pedal easy for a minute, and repeat with the other leg. That is one rep (one left-leg interval, followed by one right-leg interval). The “dead spot” will be noticeable, if not immediately, after a minute or two of the interval. This is where you are not applying force to the pedals and wasting energy. After several sessions your pedaling stroke will become noticeably smoother and “rounder”.

Low RPM intervals are designed to build specific strength. Every few sessions, as your strength improves, you will want to increase the load by shifting to a higher gear. HR should remain under your AeT throughout the interval, finishing right up to your AeT HR by the end of the intervals. If your HR is too high, try a smaller gear, if it’s too low, try a bigger gear. Cadence should remain at 60 rpm for the entire interval.  Changing hand positions each minute from tops to drops and back to tops will engage different muscles and make the time pass more quickly. It is often more difficult to perform ILTs in the drops due to the closed hip-angle and greater recruitment of the hip-flexors.

High RPM ILT intervals are designed to improve your neuro-muscular capabilities. Training the muscles to fire smoothy throughout the entire pedal stroke. These often feel quite easy for the first 60 seconds and then can become quite difficult until you train your muscles to cooperate. You will perform these in your easiest gear, with very little resistance. HR is not a concern here and should not rise much at all. If it does, your resistance is too high. As with the low-cadence ILTs, changing hand positions each minute from tops to drops and back to tops will engage different muscles and

make the time pass more easily. It is noticeably more difficult to perform the 80 rpm ILT’s in the drops due to the closed hip-angle and greater recruitment of the hip-flexors.

Aerobic Threshold (AeT) Intervals:  2-3 Hour Power 

To train the Aerobic Energy System, you want to target your AeT HR. You will pedal in a self selected gearing/cadence to achieve the target HR. Power will be approximately 85% of FTP at this effort level.

Aerobic-Strength Intervals:  

As your aerobic fitness improves you can add “hills” to your intervals for added strength benefits.

“Climbing” on the trainer can be achieved by elevating your front wheel above the rear with a trainer block, block of wood, stack of books or whatever method you choose. This elevated position engages slightly different muscles and simulates climbing on the road. With this exercise you will sit or stand and pedal, as in climbing a hill. This exercise builds both strength and aerobic fitness. The gearing is near your largest gear (high resistance), producing a cadence between 50 and 60 rpm. You will plod along at this low-cadence while changing hand positions every few minutes, from hoods and drops, to engage different muscles and keep things interesting. HR should rise after the first few minutes into your AeT HR Zone. It’s best to let it rise on it’s own and not exceed the mid-point of that zone. Again appropriate gearing/resistance will be the key if you are finding your HR too high or not high enough. When standing, weak core strength will be noticeable while performing this exercise as your back may fatigue before your legs do. If this happens, feel free to sit down for a minute to rest, before standing back up and continuing on.

Stand & Surge:

Once you have built up your “climbing” strength and endurance, you begin to elevate your HR a bit more with the addition of surges. These surges are slight increase in cadence over your “normal” climbing cadence you’ve been using to this point. In the last few minutes of your regular Strength Climb, you will surge by raising your cadence between 10 and 20 rpms for the last 15 seconds of each minute prescribed in the workout. This acceleration will increase your power output for the 15 seconds and raise your HR several beats. The surge is not a sprint or attack, but rather a quick increase in cadence. HR should rise to and slightly above your AeT HR by the last few. Again, not intended to be an all-out effort, just a simple introduction to a higher power workload. In between 15-second surges you will return to your Steady Strength cadence and your HR will recover partially before the next surge. With each surge your HR will rise slightly higher than the previous. Upon the completion of the final surge, stop pedaling completely, sit down and note your “peak HR”. Watch your HR fall and note how quickly it drops to below 100 bpm. Over the course of the series you should see your HR drop faster from higher peak HR indicating improved aerobic fitness.

6 to 8-minute AnT intervals: 32-64:00 Power 

Finally you are allowed to get your HR up over your AeT for a longer period of time. These intervals begin to touch on your anaerobic system by using a bit more carbohydrate to perform. You will focus on raising your cadence slightly each minute to achieve a gradually higher workload. These are the “comfortably hard” intervals of the series just under and right up to your FTP power (90-100%). Your HR objective is to reach your AnT HR by the end of each interval. First adjust cadence to achieve desired HR (between 90 and 100 rpm), before selecting a different gear if necessary. Recovery time is half the duration of the interval, allowing for 3 minutes of recovery between successive intervals. As with the completion of the final surge in the Stand & Surge above, upon the completion of your final AnT Interval of a workout, stop pedaling completely and note your “peak HR”. Watch your HR fall and note how quickly it drops to below 100 bpm. Over the course of the series you should see your HR drop faster from higher peak HR indicating improved aerobic fitness.

1 to 4-minute Vo2 Intervals:  8:00 to 16:00 Power

With Vo2s you get to open it up even further with shorter intervals going above your FTP. These are the painful ones! You will perform these intervals again using cadence as means to increase the workload throughout the intervals. Although these intervals are short, they will get your HR up over your AnT HR. The goal is not to work any harder than necessary, but to hit your cadence and gearing targets of 90-105 rpm. Your HR should not exceed more than 5-8 beats over your AnT HR. Power levels will be in the 110-120% FTP range. Any more than that and you are working too hard for this objective requiring more recovery and lost training time. Allow equal recovery durations between successive intervals. Upon the completion of your final Vo2 Interval, stop pedaling completely and note your “peak HR”. Watch your HR fall and note how quickly it drops to below 100 bpm. Over the course of the series you should see your HR drop faster from higher peak HR indicating improved aerobic fitness.

15-30-60-Second Anaerobic Power Intervals:  1:00, 2:00 & 4:00 Power

Now you’re bringing the power! These short bouts of intensity reach 130% to 190% of FTP. As the power increases the duration of the intervals continue to get shorter, and recovery times become longer. Gearing and cadence are now self selected allowing you to go hard and simply focus on hitting the target power levels. Recovery durations are now 3x the length of the interval allowing for near full recovery before the next interval. HR becomes irrelevant due to the short duration of the intervals. Despite the high effort, these intervals don’t hurt too badly since they are over by the time they start to hurt!

Peak Power Sprints:  0:05 Power! 

The second to last progression in the metabolic energy system chain (with movement strength (ie. weight lifting) being the last link in the chain). Anaerobic Power at it’s finest. No oxygen needed! These intervals are performed in a larger gear from a stand still or slight “rolling start”. You kick hard and crank up to full power over 5-10 seconds. You’re done as soon as you peak the cadence out and/or reach peak power for the effort. Power will jump towards 300% of FTP!

Steady Spin & Spin Down:

Your cool-down exercise. The Steady Spins gives you a chance to spin your legs out, get some fresh blood in there and begin the recovery process. You are back in your easiest gear with minimal resistance. Hold the specific rpm listed in the workout (or slightly higher if you like) for the time prescribed. HR should maybe reach the lower limits of your AeT HR Zone. Adjust resistance (or lower cadence) as needed. After the extended time spinning, you begin to gradually bring the cadence down (along with HR) with the Spin Down. Bring your cadence back down to 80 rpm over a few minutes until you are breathing normally and no longer perspiring. Wipe the sweat off your face and body, grab your recovery drink and call your workout finished!

Interested in giving it a try yourself?

Download via Training Peaks:

All Programs include:

  • Full Testing Protocol and Training Zone Calculator to identify HR and Power zones and track progress.
  • Structured training sessions uploadable to your app of choice (Zwift, Wahoo, Garmin, Trainer Road, etc.)
  • All the strength training details, including videos and set/rep schemes and calculated loads specific to your ability (if applicable)
  • Bonus weekend training ride suggestions for either indoors or out.



Written by Cody Waite, professional endurance athlete, endurance sport coach and founder of Sessions:6 Sport Performance. Looking for help with your endurance sport training? Check out S:6’s Training Plans, Team Programs, and  Personal Coaching options created to fit your needs and budget.




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