The main characteristic of any endurance based training programme is a large training volume of which the majority of the training volume (>50%) will be devoted to the development of a strong aerobic base fitness level, involving training at an Easy/moderate training intensity (Pate and Branch, 1992; Martin and Coe, 1997). Training at this level predominantly involves the recruitment of slow twitch or type I muscle fibres. These are highly aerobic highly efficient muscle fibres. This training intensity allows for high volumes whilst placing a low level of stress on muscular structures and physiological systems (Pate and Branch, 1992). When training at this level stress hormones remain relatively low and therefore athletes can perform large volumes of training in this zone without putting themselves at a great risk of overtraining.
Physiological adaptations to aerobic base training
Physiological Adaptations to this type of training include: type I fibre development and increased; capillarisation, blood volume and number of red blood cells, intramuscular fuel storage, mitochondrial size and density, Improved aerobic energy metabolism (free fatty acid utilisation), oxidative glycolytic enzymes, Cardiac size and output, muscular capillarization – which in turn increases blood flow to the muscles, and improved muscular endurance (Martin and Coe, 1997; Neumann et al., 2000).
The benefits of aerobic base training
A high training volume may be particularly important for increasing the %VO2max that can be sustained and may lead to improvements in the economy of motion (Noakes, 1991; Jones, 1998). In recent years many western coaches have moved away from high volume training and concentrated more on High Intensity Interval Training (HIIT)sessions.
Aerobic base training appears to play an important role in preparing the body for the greater demands of higher intensity training (e.g. Lactate threshold training, HIIT sessions) through all the physiological adaptations discussed above. If an athlete undertakes HIIT sessions, without the development of a strong level of base fitness, they will increase their risk of injury; and because their body is not fully prepared they will gain less benefit from the HIT sessions compared to if they had undergone a good period of aerobic base training. It is also important to remember that athletes that utilize greater training volumes will be able to undergo a greater volume of hit sessions than less well prepared athletes.
Types of aerobic base training
- Recovery Training: Typically involving training at 60-70%HRmax and would often be utilized the day after a particularly stressful training session.
- Basic Endurance Training: Involving training at 70-80%HRmax for a duration of 20-60minutes. This would generally make up the bulk of endurance training, and this type of training might be typically used 5-10times per week.
- Long Endurance Training: Involving training at 70-80%HRmax but of a greater duration than basic endurance. Typically from 60minutes up to 5hours or more, depending on the sport. Long endurance training would typically be performed from 1-2 times per week.
Moderate intensity endurance training is unlikely to lead to improvements in VO2max in highly trained athletes (Acevado and Goldfarb, 1989; Londere, 1997), but may condition and refine the recruitment of the specific muscles utilised for the activity, whilst reducing the recruitment of antagonist and/or excessive recruitment of stabilising muscles (Fallowfield and Wilkinson, 1999). Moderate intensity training plays a key role in the development of basic endurance and, therefore, should make up a major proportion of the total training volume (Neumann et al, 2000).
Research looking at training volumes of runners suggested there is no measurable cardio-respiratory improvement (VO2max) when training volume is greater than 60-90mi/wk – around 10-15hours of training a week (Costill 1986). However, the high training volumes currently employed by elite endurance athletes may be important for the improvements in Economy of motion that occur over a number of years (Coyle, 1991; Fallowfield and Wilkinson, 1999; Jones, 1998). Although these high training volumes are unlikely to impact on measures of aerobic fitness like the VO2max, it can lead to significant improvements in the functioning of individual muscle fibres and is particularly important for the development of slow twitch muscle fibres. A large aerobic base training volume is believed to be particularly important for enhancing the lactate threshold, exercise economy, mitochondrial size and density, muscle capillarization and aerobic energy systems.
Aerobic Base Training Summary
- Aerobic base training involves training at low to moderate training intensities (60-70%HRmax) and predominantly involves the recruitment of slow twitch (type I muscle fibres)
- A large portion (>50%) of any endurance based training programme should be devoted to aerobic base training.
- Aerobic base training helps to prepare the body for the physiological demands of higher training intensities e.g. tempo training, high intensity interval training
- The relatively low intensities utilized during aerobic base training allow athletes to complete large training volumes with a reduced risk of overtraining, when compared with higher intensity training (>LT)
- A large volume of aerobic base training appears to be particularly important for the development of the lactate threshold, exercise economy, fatigue resistance, mitochondrial size and density, enhanced aerobic energy pathways