If you want a fast triathlon performance, you need to know about Durability
In the world of cycling, durability, also known as fatigue resistance, is the ability to resist fatigue throughout the duration of a ride or race. It refers to the decay of physiological performance over time. In modern racing, the ability to produce high power outputs after several hours of riding is a key cycling ability. The winning moves are often made in the closing stages of an event, highlighting the importance of being able to perform well after prior work during tough races and challenges. Riders with better durability can sustain a higher percentage of their "fresh" state and typically achieve better results.
Cycling durability in triathlons differs from road racing. Triathlon cycling typically involves a steadier intensity, and athletes must also prepare for the run that follows the bike leg. While professional triathletes encounter attacks and surges, these are generally less intense than in road races. Triathlons can be unpredictable, with athletes needing to navigate drafting rules and attempts to disrupt pace lines. This requires them to handle short bursts of high intensity, often at the beginning of the race, while still maintaining high relative power later on.
For most amateur triathletes, the dynamic nature of professional races is less applicable. Amateurs usually focus on maintaining a consistent and high power output over extended periods.
For triathlon, durability focuses on maintaining high power output while minimising fatigue for the run. On some courses, sustained high power on climbs is also key to a fast split, whilst avoiding fatigue throughout the event.
Fatigue itself is an incredibly complex phenomenon.
The key physiological factors contributing to fatigue resistance in cycling performance include:
Metabolic Flexibility and the Ability to Use Fats for Fuel
Fats serve as the primary fuel source at lower cycling intensities, while carbohydrates are essential for high-intensity efforts. Since glycogen (carbohydrate) stores are limited and difficult to replenish during exercise, the ability to utilise fats efficiently conserves glycogen, delaying fatigue and reserving fuel for later high-intensity efforts. This ability is highly trainable, allowing trained athletes to oxidise fats at higher rates than untrained individuals.
Metabolic flexibility, the efficient switching between fuel sources, can be improved through specific training and nutrition strategies, including low-intensity rides, fasted training, and lactate utilisation sessions.
Resistance to Muscular Damage: Muscle damage, in the form of tearing and swelling, occurs after extended periods of cycling and contributes to fatigue. While less pronounced than in activities with higher impact, it still plays a role. 'Muscular endurance' intervals build resistance to muscular damage. Maximal strength training may also help enhance endurance by potentially reducing muscular damage; one theory suggests that increased strength means muscle fibres are worked at a lower percentage of their maximal load for a given power output.
Resistance to Central Fatigue During extended periods of riding, neural activation of muscle fibres by the central nervous system decreases, a phenomenon known as central fatigue. Studies suggest that central fatigue contributes to overall fatigue, potentially becoming more dominant in longer activities.. Long endurance rides at a controlled ‘Zone 2’ intensity probably help with resistance to central fatigue.
Beyond these primary factors, other physiological and biomechanical aspects contribute to durability:
Efficient Neuromuscular Pathways Efficient neuromuscular pathways are crucial for optimising muscle recruitment, coordination, and power output. Training methods like torque or low cadence work can stress motor units and improve these pathways, enhancing the ability to produce power.
Gross Efficiency Gross efficiency is the ratio of mechanical work output to energy expenditure.. Improving this by optimising bike fit, pedalling technique, and aerodynamics helps minimise energy loss. Strength or resistance training off the bike can also be beneficial. Maximising mechanical efficiency conserves energy and delays the onset of fatigue.
Physiological Adaptations from Training Volume Accumulating greater volume, particularly time spent in low-intensity zones (Zone 1 and 2), is a main focus area for improving durability. High volume, low-intensity training is needed for the body to develop muscular endurance and train smaller muscle groups that engage when the main ones are tired. It also contributes to peripheral adaptations like increased capillary density and mitochondrial content, which appear to respond to large volumes of low-to-moderate intensity training even in elite cyclists.
Physiological Benefits of Strength Training In addition to potentially reducing muscular damage, strength training can enhance endurance in several ways. Increasing peak power production can mean that at a given sustainable output, muscles operate at a lower percentage of their maximum, allowing for improvements in functional threshold power (FTP) through enhanced muscular potential.
Resistance training can also increase muscle recruitment, enabling riders to use a wider range of muscles, like hamstrings, calves, and glutes, to share the load with the quadriceps. This sharing of the workload across more muscle groups increases fatigue resistance. Furthermore, strength training can improve muscle fatigue resistance, which is beneficial for high-power efforts late in races.. It also helps maintain bone density, important in non-load-bearing activities like cycling.
While not purely physiological, psychology and mental resilience are also vital for performance and durability. Training mental skills helps manage the mind and performance anxiety, enhancing the ability to push deeper and longer.. Mindfulness, for example, mediates the relationship between mental toughness and pain catastrophising.
Achieving fatigue resistance in cycling requires a holistic approach that addresses these various physiological and biomechanical factors.
