1. Why Power

2. Topics • What is power and how can we measure it? • Principles of training

3. What is Power? Power is simply the amount of mechanical work or energy you expend in a given time frame measured as a watt.

4. Power = Work = Joule Time Sec Power for Bike & Rider All the Forces Resisting Movement x Speed Power at the Hub (or crank) Torque x Cadence or Angular Velocity Push Harder or PedalFaster

5. Kjoules to Kcals 1 Kcal = 4.186 Kjoules 1 Kcal 4.186 Kj E.g., Work on Bike 1000 kj x = 239 Kcal The number of kcals burned by your body is actually much higher and depends on how mechanically efficient you are. Most humans are about 22% efficient on a bike, meaning only 22% of the kcals you burn actually goes into the bike. 239 ÷ .22 = 1086 kcals burned by the body

6. Points of Reference • 1 horse power = 746 watts • A 68 kilogram (150 lb) rider with an 8.6 kg (19 lb) bike at 32 kph on flat ground with no wind requires about 177 watts • 56.5 W are required to press a 20 lb dumbbell 25 in. Overhead in one second • Tour de France winners can generate 465 watts for over 30 minutes

7. Why Use a PowerTap? • Power is the most objective measure of intensity • RPE is too subjective by itself and relies on too many factors • Speed changes with terrain • Heart Rate response lags behind actual effort and measures body’s response, not the work being done

8. The principles of training have not changed.

9. Specificity • Training adaptations are highly specific to the activity and environment. • Pattern of power output. • Joint and body positions. • Speed of movement. • Temperature, humidity, altitude, wind. • Availability and type of food. • Terrain. • The best way to develop better training strategies is to better understand the demands of racing.

10. Training is Overload • A training stimulus is only a training stimulus if the “load” is greater than recently experienced. • Overload: greater force, faster speed, higher power, longer duration, more work. • In order to adapt the body must be placed under an unfamiliar and stressful load that acutely disturbs homeostasis.

11. Overload Concerns: Fatigue • Overload training is in addition to other life stressors. Account for the combination. • Overload is fundamentally about exceeding previous performance limits and exceeding limits can lead to illness, injury, and sometimes over-reaching/overtraining.

12. Recovery • Overload phase ends with an acute drop in performance, whereas the recovery phase ends with a restoration or increase in performance. Choose recovery rather than trying to have a perpetual overload. • Adaptive processes occur during the recovery phase (e.g., protein synthesis, restoration of homeostasis). • There is no such thing as overtraining, just under-resting.

13. Individuality • Fields are born, winners are made. • Each individual is their own scientific experiment.