VT1 and VO2- exercise induced changes
Marathon runners usually start training several months before a big race. The goal is to be able to cover the distance in the least amount of time by maintaining a good pace for a long time. Let’s have a look at how the parameters which signal the performance of the human engine change with this training.
I tested 2 regular full marathon runners 6 months apart- at the start of their running season and when they were at their peak. During this period, they had put in at least a 1000 kms in training and were training to a plan designed by a coach. The drop in weight was less than 5% (2-3 kg) during this period. They suffered no major injuries that derailed their training and were able to meet their goals for the season.
- Changes in VO2 max- NONE. Despite training hard, there was no change in the HR or the O2 capacity
- Changes in VT1- 12-15% (1.3kmph) improvement in the running speed at the same O2 consumption. HR increased by 10 bpm over the first test.
The maximum improvements to VO2 levels are seen during the growth phase between the age of 15-20. Improvements are seen when deconditioned or sedentary people take up regular training and when the training program is especially intense. VO2 levels can also increase due to a massive drop in weight since the VO2 values are calculated per kg weight.
Both the runners tested were in their 40’s and were already fit marathoners. The maximum oxygen burning capacity, or the size of human engine is quite resistant to improvement in already conditioned athletes. The capacity of the engine tends to go down with age. Therefore, significant changes in Oxygen burning capacity were not expected and were not seen.
However, there is always a scope to improve the tuning of your engine. This makes the engine more efficient and at the same oxygen consumption, it can generate better performance. When you undergo a systematic training plan which balances your improvements with the training load, several changes happen at the level of your muscles. These include improvements in blood supply, quality and quantity of enzymes present etc which helps in better utilization of the fuel and helps you run faster.
It is reasonable to assume that most amateur marathon runners get better by fine tuning their engines. This requires time, miles in training and a regular well-designed training plan which includes not just long runs but shorter sharper runs to really force the body to adapt and improve.