Cycling is a sport that demands not only physical strength but also mental resilience to withstand the rigors of long rides, steep climbs, and challenging terrain. Central to achieving success in cycling is the ability to resist fatigue throughout the duration of a ride or race.
The saying “it’s not how you start, but how you finish” could not be more applicable in modern racing. Racing has evolved and so has our understanding of what it takes to win races. The hottest term recently is “durability,” previously termed “fatigue resistance.”
Durability refers to the decay of
physiological performance over time.
It can be measured by assessing a rider’s decrease or change in their power-duration curve under fatigue. Fatigue is an incredibly complex phenomenon, yet we can quantify and objectify various levels of fatigue using power data. Cycling races are a process of selections, with typically the final moves or winning efforts coming towards the end of the race. Riders with the best durability, i.e., the ability to sustain the highest percentage of their “fresh” state, will typically achieve better results.
HOW DO WE MEASURE DURABILITY?
Going back to first principles, power is simply energy expenditure in Joules, a standard unit of energy. We measure kilojoules (kJ) or calories as energy expenditure. Humans are typically 25% efficient in converting stored energy to mechanical energy (power) on the bike; therefore, the 4.184 kJ in 1 calorie can be assumed as 1 kJ when measuring power output. You can add kJ to your cycling computer and measure this during a ride, as long as you have a power meter on your bicycle.
We can then assess performance after doing a specific amount of work. We can classify durability as the percentage of “fresh” performance that can be done after a specific amount of work. For example, kJ intervals of 1000, 1500, 2000, 2500, 3000, etc. By doing this, we can measure riders’ peak power output for a specific duration of time (known as mean maximal power) or we can perform “power profiling”; the assessment of both “fresh” power duration curves (modelled data from all performances over a period of time), as well as power duration curves after specific energy expenditure threshold. There are durability reference ranges for rider training status, as well as durability characteristics of rider types such as sprinter, all-rounder, and general classification rider.
Things are a little more complicated in that we can either assess after a particular absolute work performed (3000 kJ) or work per kilogram body mass (40 kJ/kg). The former would favour larger athletes and the latter would favour smaller athletes. There is no consensus on which one should be used.
Lastly, it is now clear that Durability is primarily affected by the amount of work done above the critical power (similar to FTP).
A steady-state ride of 3000 kJ done at 90% of FTP is unlikely to have a significant impact on durability, whereas a series of intervals done above FTP will.
This means assessing Durability requires a standardised session before measuring the drop off in power duration or MMP. We typically use a protocol of 5 x 8 min efforts of 105% FTP with 15min recovery periods before measuring a specific MMP performance.
HOW DO WE IMPROVE DURABILITY?
Improving your durability takes time and involves the careful layering of the correct training and principles over time, both on and off the bike.
1. TRAINING VOLUME
Training load management involves carefully balancing volume, intensity, and frequency of training sessions to stimulate physiological adaptations while minimising the risk of overtraining and injury. Cyclists should follow a structured training plan that incorporates progressive overload, adequate rest and recovery, and periodisation to optimise performance gains and resilience against fatigue. Time spent in the low-intensity power domain and accumulating greater volume here is one of the main focus areas. This refers to your typical zone 1 and 2 training in a 5-zone power model.
2. NEUROMUSCULAR PATHWAYS
Efficient neuromuscular pathways play a critical role in optimising muscle recruitment, coordination, and power output during cycling. Torque or low cadence work is an effective on-the-bike exercise that can stress your motor units and improve these neuromuscular pathways. We see specific absolute and relative torque values across a range of athletes and can measure and improve these over time. Power is simply a function of torque (force on the pedals) and angular velocity (cadence); therefore, improving these torque values will, by definition, improve one’s ability to produce power.
3. METABOLIC FLEXIBILITY
Metabolic flexibility refers to the ability of the body to efficiently switch between different fuel sources, such as carbohydrates and fats, during exercise as well as using carbohydrate in the most efficient way (oxidatively). Cyclists can enhance metabolic flexibility through training and nutrition strategies that promote fat oxidation and spare glycogen stores. This includes incorporating low-intensity, long-duration rides, fasted training sessions, and sessions focused on the body’s ability to utilise lactate as a fuel source. Being able to access greater amounts of intramuscular triglycerides (IMTG) at low to moderate intensities will provide glycogen sparing for later efforts in races. As exercise intensity increases, our reliance on glycolysis to produce energy increases. Lactate, a by-product of glycolysis, is produced at a progressively greater rate at higher intensities. Type 1 muscle fibres within the same muscle or at other sites in the body can use this lactate as a fuel, reconvert it into pyruvate, and use it in the respiration cycle. This allows efficient use of endogenous fuel sources and better recovery and lactate clearance after hard efforts in races. To find out more about your metabolic flexibility, you can book a metabolic profiling test at one of our laboratories.
4. GROSS EFFICIENCY
Gross efficiency refers to the ratio of mechanical work output to energy expenditure during cycling. Improving gross efficiency involves optimising factors such as bike fit, pedaling technique, and aerodynamics to minimise energy loss and maximise power output. Cyclists can enhance gross efficiency by ensuring proper bike fit, maintaining a smooth and efficient pedal stroke, and reducing aerodynamic drag through equipment and body positioning adjustments. Strength or resistance training off the bike can also be beneficial. By maximising mechanical efficiency, cyclists can conserve energy and delay the onset of fatigue during long rides or races. To optomise your biomechanics, you can book a fitment session in one of our laboratories.
5. NUTRITION
This is an area where enormous performance improvements have been and continue to be made. Carbohydrate ingestion has evolved, moving from the previous standard of 60 grams per hour (g/hr) to 90 g/hr and now up to 110 – 120 g/hr based on race demands. This strategy helps in sparing muscle glycogen for crucial moments in races. Humans have approximately 600g of stored glycogen in the liver and muscles, and by ingesting a significant amount of carbohydrates during a race, these reserves are spared for when they are most needed. It must be stressed that the correct carbohydrate mixes need to be ingested to be able to absorb exogenous (ingested) carbohydrates at such high rates. The fuelling should be through a mix of maltodextrin and fructose with a ratio of 50:50 through to 66:33 being most optimal. Avoid other carbohydrates such as isomaltulose. These are not performance carbohydrates.
6. PSYCHOLOGY
One often overlooked aspect of performance and durability is psychology and mental resilience. This area can be trained and is vital to an athlete’s success. A rider can have the best training and physical conditioning, but knowing how to manage your mind and performance anxiety is crucial for achieving personal bests and results. The use of sports psychology among athletes of all levels is often overlooked but can provide valuable skills and tools for various situations. Developing the right mental tools and foundations is essential for approaching and executing training and racing. Toughness and mental skills are developed over time, enhancing your ability to dig deeper, go longer, and execute decisive attacks.
Achieving fatigue resistance in cycling requires a holistic approach that addresses various physiological, biomechanical, and environmental factors. By optimizing training load, improving metabolic flexibility, neuromuscular pathways, nutrition, and gross efficiency, cyclists can improve their ability to delay fatigue, allowing them to perform at their best on the bike.
One Comment on “DURABILITY: HOW RESISTANT ARE YOU?”
Björn Pienaar
Oct 14, 2024 at 12:19 pmGreat article, thx.