Another study (from Clarence Bass's article) :
Izumi Tabata and his colleagues at the National Institute of Fitness and Sports in Tokyo, Japan, compared the effects of moderate-intensity endurance and high-intensity intermittent training on V02max and anaerobic capacity. (Medicine and Science in Sports and Exercise (1996) 28, 1327-1330).
Interestingly, the high-intensity protocol had been used by major members of the Japanese Speed Skating team for several years; it's a real-world training plan. As you will see, however, the protocol is unique among aerobic training programs for its intensity and brevity.
Many studies have been done on the effect of training on V02max, but little information has been available about the effect on anaerobic capacity. That's because until recently methods for measuring anaerobic capacity have been inadequate. This study used accumulated oxygen deficit to measure anaerobic energy release, and is one of the first to measure the effect of training on both aerobic and anaerobic capacity.
Notice that the duration of the moderate-intensity and the high-intensity protocols are drastically different: (excluding warm-ups) one hour compared to only about 4 minutes per training schedule.
Tabata's moderate-intensity protocol will sound familiar; it's the same steady-state aerobic training done by many (perhaps most) fitness enthusiasts.
Here are the details : In the moderate-intensity group, seven active young male physical education majors exercised on stationary bicycles 5 days per week for 6 weeks at 70% of V02max, 60 minutes each session. V02max was measured before and after the training and every week during the 6 week period. As each subject's V02max improved, exercise intensity was increased to keep them pedaling at 70% of their actual V02max. Maximal accumulated oxygen deficit was also measured, before, at 4 weeks and after the training.
A second group followed a high-intensity interval program. Seven students, also young and physically active, exercised five days per week using a training program similar to the Japanese speed skaters. After a 10-minute warm-up, the subjects did seven to eight sets of 20 seconds at 170% of V02max, with a 10 second rest between each bout. Pedaling speed was 90-rpm and sets were terminated when rpms dropped below 85. When subjects could complete more than 9 sets, exercise intensity was increased by 11 watts.
The training protocol was altered one day per week. On that day, the students exercised for 30 minutes at 70% of V02max before doing 4 sets of 20 second intervals at 170% of V02max. This latter session was not continued to exhaustion. Again, V02max and anaerobic capacity was determined before, during and after the training.
In some respects the results were no surprise, but in others they may be ground breaking. The moderate-intensity endurance training program produced a significant increase in V02max (about 10%), but had no effect on anaerobic capacity.
The high-intensity intermittent protocol improved V02max by about 14%; anaerobic capacity increased by a whopping 28%.
Dr. Tabata and his colleagues believe this is the first study to demonstrate an increase in both aerobic and anaerobic power. What's more, in an e-mail response to Dick Winett, Dr. Tabata said, "The fact is that the rate of increase in V02max [14% for the high-intensity protocol - in only 6 weeks] is one of the highest ever reported in exercise science
." (Note, the students participating in this study were members of varsity table tennis, baseball, basketball, soccer and swimming teams and already had relatively high aerobic capacities.)
The results, of course, confirm the well-known fact that the results of training are specific. The intensity in the first protocol (70% of V02max) did not stress anaerobic components (lactate production and oxygen debt) and, therefore, it was predictable that anaerobic capacity would be unchanged.
On the other hand, the subjects in the high-intensity group exercised to exhaustion, and peak blood lactate levels indicated that anaerobic metabolism was being taxed to the max. So, it was probably also no big surprise that anaerobic capacity increased quite significantly.
What probably was a surprise, however, is that a 4 minute training program of very-hard 20 second repeats, in the words of the researchers, "may be optimal with respect to improving both the aerobic and the anaerobic energy release systems
." That's something to write home about!