Continuous and interval training - update
Brian Mackenzie reviews the pros and cons of interval and continuous training.
Continuous training is when an athlete exercises in a steady aerobic way and interval training is characterised by repetitions of work with a recovery period following each repetition. Continuous training can be broken down into the following sub-divisions, which have slightly different effects upon the energy pathways:
Interval running enables the athlete to improve the workload by interspersing heavy bouts of fast running with recovery periods of slower jogging. The athlete runs hard over any distance up to 1k and then has a period of easy jogging.
During the run, lactic acid is produced, and a state of oxygen debt is reached. During the interval (recovery), the heart and lungs are still stimulated as they try to pay back the debt by supplying oxygen to help break down the lactates.
The stresses put upon the body cause an adaptation including capillarisation, strengthening of the heart muscles, improved oxygen uptake and improved buffers to lactates. All this leads to improved performance, in particular within the cardiovascular system.
Before undertaking interval training, a few simple rules should be understood:
Circuit training is a standard method of interval training.
The benefits of interval training
In planning training programs, controversy still exists as to the optimum duration of the workloads needed to gain maximum results. It would seem a waste of effort to train for longer periods than necessary for the same gain in fitness. In an attempt to address this problem, a research project in Thunder Bay, Ontario, Canada, randomly assigned 21 females, aged between 18 and 26, into two groups before embarking on a seven-week training programme.
The subjects were tested in a laboratory to evaluate their maximum oxygen uptake (VO2 max), ventilatory and lactate thresholds, all key indicators of aerobic fitness. All the subjects trained at 85% of VO2 max for the first two weeks, with a 5% increase every fortnight. Thus, they trained at 85% for the first fortnight, 90% for the second fortnight and 95% for the third. The frequency of training, which continued to exhaustion, was four times each week. Group one trained with 30-second interval workloads, while group two used a two-minute workload. Both groups, however, continued with work to recovery ratio of 1:1.
At the end of the seven-week training programme, the subjects were retested in the laboratory. It was discovered that there was a significant increase in VO2 max, ventilatory threshold and lactate thresholds of all subjects. There was, however, no significant difference between the two groups utilising the different workload durations.
This might suggest that there is little difference in using 30-second or two-minute duration workloads, while both forms of workout have strong training effects for aerobic fitness.
The study does not, however, state the initial fitness levels of the subjects, which has an effect upon the possible gains in fitness achievable. Further, the training does not mimic a realistic training programme, where utilisation of different energy pathways should be involved, including the important steady-state component of training.
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About the Author
Brian Mackenzie is a British Athletics level 4 performance coach and a coach tutor/assessor. He has been coaching sprint, middle distance and combined event athletes for the past 30+ years and has 45+ years' experience as an endurance athlete.