Methods of cardio-respiratory training is a controversial subject at the best of times. In recent years, long steady distance training has received much criticism in favour of a more popular method of interval training. BOTH methods of training have valuable aspects and the exclusion of one for the other will surely limit the athletic potential of any endurance athlete.
LSD training is great for: reducing body fat%, inducing significant central cardiovascular adaptations such as increased volume of blood returning to the heart, expanding blood plasma volume and reducing resting heart rate. Reducing resting heart rate opens the training window from rest to maximum i.e. you will find your maximum exercise intensity much later in training meaning that you will go for longer. LSD training has specific benefits to events which last 60min or over even if intermittent in nature e.g. soccer, tennis and rugby. It has been demonstrated for over 40years to be a primary method for inducing mitochondrial biogenesis i.e. it develops the size and number of muscle powerhouses which enable us to perform exercise. It forms the basis for the development of an endurance base in adolescence which can last for a lifetime.
Interval training on the other hand, can be classified as extensive or intensive. Extensive interval training emphasizes “long”, high volume work periods (3-5min) with incomplete rest periods (1min) whiles intensive interval training emphasizes shorter work periods bordering on aerobic-anaerobic training. Recent research shows that high intensity interval training (intensive) may also induce mitochondrial biogenesis and therefore is an important training method for developing aerobic fitness (Gibala et al. 2011)