This is a summary of the key learnings I took from reading The Power Meter Handbook by Joe Friel, founder of Training Peaks.
Power meters are useful as they can help monitor your energy expenditure on hills, headwinds, tailwinds and across the whole course, so you finish strong.
Power is how much work you are doing and how fast you are doing it. Power results from an interplay of force, distance and time.
Power = force x velocity
On a bike, force is what you put into the pedals, velocity is how fast you are turning the pedals, this is also referred to as cadence. A power meter measures these two things. Cadence is often referred to as RPM or revolutions per minute.
Therefore, if you increase force or increase cadence, you increase power, and vice versa.
Power Meters Vs Other Metrics (HR, RPE & Speed)
Heart rate (HR) is affected by ‘outside’ forces such as diet, race day excitement and psychological stress. In training, HR is slow to respond when you are doing intervals, so in the first few minutes you are forced to guess how hard to go. HR tells you how hard you are working based on your body’s demand of fuel and oxygen, not how you are performing. HR and rate of perceived exertion (RPE) are input values, they tell us what effort you are working to achieve the output, what the rider is experiencing.
Output measures are power and speed. They tell us what was accomplished on the ride and are directly linked to performance.
When compared with power, HR and RPE tell us about the rider’s fitness. When power is high and HR & RPE are low compared with the rider’s previous rides, we know the athlete is fitter and faster.
Cycling with Power
Power meters are useful to help plan sessions and intervals. You can analyse previous race efforts to establish the race requirements then plan training accordingly. Set up your bike computer to include the following fields - time, speed, distance, 10sec average power, HR and cadence. Focus primarily on completing the intervals or workout at the desired power and cadence. Use HR to tell you how efficiently you are riding.
Normalised power (NP) is the expression of the average power adjusted for a range of variability and therefore more accurately represents the metabolic cost or effort of a ride than average power. Every time you spike power, more energy is expended than if you rode in a stead state with no spikes. Therefore, NP is telling us what the workout felt like. In a steady state flat workout average power & NP will be very similar. In a variably paced road ride with intervals, surges and hills the average power & NP will be quite different.
Functional Threshold Power
Functional threshold power (FTP) is the highest average power you can sustain for a 60min steady state ride. It is usually around your lactate threshold or when your body can balance energy supply and energy demand. We use your FTP to create accurate zones to train with. Your FTP is roughly equivalent to a 40km time trial or NP in a 1hr criterium. Your FTP may be lower on TT bike vs road bike due to changes in position and aerodynamics.
The 50-40-30-20-10 Rule
Zones are set within Training Peaks based on your FTP. Workouts are prescribed within these zones. Workouts will incorporate one or combinations of the types of training and prescribed in the zones listed below.
Training With Power for Cycling
Cycle Training Types
Your key workouts must reflect the exact levels of intensity demanded by the event in order for you to become fit for it. There are six types of training you can perform on the bike. Each discipline of cycling (road, track, MTB, TT) requires different combinations of these. Mix of these types of training help meet the demands of racing
Aerobic endurance - extended steady rides at zone 2, low zone 3; at your aerobic threshold (not lactate threshold); typically 2hr+.
Muscular force - zone 7; very short low cadence, high resistance efforts; usually on a hill.
Speed skills - pedalling drills, high cadence spinning and isolated leg training. Improves pedalling efficiency.
Muscular Endurance - produce physiological muscle adaptations & ability to process lactate; upper zone 3 & zone 4; ~ 20min duration’ sweet spot’ or ‘tempo’ efforts with ~ 5min recovery; improves your capacity to maintain lactate threshold / FTP for longer period of time.
Anaerobic endurance - common road & MTB racing, improves aerobic capacity (VO2 max); can improve VO2 max for triathletes; efforts 2-4min duration in zone 5 & 6.
Sprint power - common road cycling; also called ‘jumps’ where you begin at moderate to low intensity with several brief all out sprints 6-8 pedal strokes often hill sprints in zone 7.
Power Data Analysis
Intensity Factor (IF) is a value given in Training Peaks when you upload a workout. It is used to compare the intensity of the workout to other workouts and compare to other riders. An IF of 1.0 means you rode at your FTP.
In the build period (final 12 weeks before key event), your training intensity should begin to reflect the intensity you will race at. IF is an easy way to quantify this.
Variability index (VI) is the comparison of NP and average power. For a steady state ride VI = 1.05 or less, VI of 1.0 would indicate perfect pacing. This can be used to help athletes execute better pacing strategies. If speed increases, you use more energy to sustain that speed. This might not be suitable for the type of racing you are doing, particularly long distance triathlon.
Efficiency Factor (EF) is NP / average HR. It measures improvements in aerobic efficiency on similar courses over time. EF should rise over time in base period. If it levels off that indicates that aerobic endurance is at peak level & you’re ready to move onto more challenging work. Cue moving from base period to build period.
Training Stress Score (TSS) is a way of mathematically combining duration and intensity to produce a ‘score’. Hard training causes stress. Your body responds to stress by becoming fatigued. Then given adequate recovery will adapt to the new level of stress = fitness. An increase in the score, means you have increased your workload. Training Peaks does a daily rolling average of your TSS for six weeks.
The purpose of this block is to improve your aerobic fitness. The focus is on building duration of workouts via aerobic endurance training in zones 2 / low zone 3. Focus on your weaknesses first in these workouts.
Once you are aerobically fit from the base period, change your training to reflect the demands of your race. Focus on duration & intensity = become faster. Include terrain familiarisation, event nutrition, pacing rehearsal & equipment selection. This is typically done in the 12 weeks leading into your key event. In the build phase at least one workout should have a TSS you would expect in the race. It so you can gradually adapt to the race day TSS. Early in the build phase the focus is on duration, then shift to intensity. Focus on your weaknesses second in the workouts, in favour of working on what is required most importantly on race day.
Recovery Period (+ Recovery Sessions)
Peaking or tapering is a periodisation method to reduce duration of workouts while maintaining race like intensity. Short tapers may be used when training has not gone well in the build period, and another week of high TSS is needed. This is usually in the final 1-3 weeks of your training before your key event.
Recovery sessions are useful throughout the week, between key workouts. They involve riding in zone 1. When you are fatigued it is an effective way for advanced athletes to rejuvenate the body while maintaining pedalling economy with a high cadence. These workouts can include speed skills / pedal efficiency sessions. If you do this ride in zone 2 or 3, residual fatigue will linger into the next key workout. Over time this results in mediocre training sessions and reduced race performance.
A highly fit but tired athlete doesn’t perform as well as a slightly fit but well rested athlete. Fatigue is more powerful than fitness, fitness decreases at a slower rate than fatigue. Fatigue must be eliminated even if that means giving a little fitness. Training stress balance (TSB) increases as an athlete ‘comes into form’. On race day, we aim for athletes to have a TSB of +15 to +25.
Key Take Home Points for Training with Power for Cycling
Training with power for cycling gives you the data to help pace your races and execute training to replicate your races.
Key workouts are the most important in your week and have the most influence on race readiness. Each workout contains a purposeful combination of intensity & duration, prescribed using zones.
Do your recovery workouts in zone 1 to help prepare the body for the next high stress workout, without causing extra fatigue which may impact on upcoming sessions.
Training Peaks relies on accurate recording of data and input of accurate zones to produce usable data / scores to inform coaches & athletes of training. Inaccurate data & zones means the above mentioned scores are meaningless.