I think that there are two questions here:

1) what is the best exercise prescription to optimise fat loss, and

2) what is tolerable and motivating for an overweight population.

For the first question, it is clear that the higher the intensity, the greater the energy expenditure (see Romijen et al. (1993) Am J Physiol 265: E380-E391). But this obviously needs to be balanced with the decrease in exercise duration as the intensity increases. Interval training offers the advantage that the short rest periods allow a high intensity to be continued for longer. Another advantage of intervals training is that metabolism is raised during the rest periods. Small-sided games can offer similar advantages, but may be more motivating for some (and may have additional advantages such as an increase in muscle mass).

For the second question, the exercise needs to be tailored to the individual. The above provides some indications on how to optimise energy expenditure, but ultimately the choice needs also to consider the personal interests and motivation of the individual.

Thanks David

Of course I know the negative relationship between intensity and duration of exercise, but the question that confused me is the question that: is there a formula that can tell us what is perfect duration for intervals? and what is a perfect intensity for its work and its recovery?

I should use 2 min intervals or 4 minutes? or may be longer time

If I select 4 min or longer it is clear that using lower intensity is rational.

based of your suggestion "the exercise needs to be tailored to the individual", I should doing a pilot study to find it experimentally

based of your experiences and information,I s it better to use equal time to work and recovery?

I would be very graceful if let me know your Idea, Daivid

thanks a lot

best regards

Hiwa

Hiwa, I understood what you mean.

I think a good paper that will clarify some doubts is: SEILER, S., and K. J. HETLELID. The Impact of Rest Duration on Work Intensity and RPE during Interval Training. Med. Sci. Sports Exerc., Vol. 37, No. 9, pp. 1601–1607, 2005.

Anyway, some tips: an intensity around 80-85% VO2max is the first to justify an interval training. From this submaximal range you could choose for longer work intervals (4-5min) and a exercise:rest ratio of 4:1 or 3:1. As you increase the intensity (e.g 3-5%) you need to decrease the work interval (2-3min) and the ratio could be fine at 3:1 or 2:1. If you select an intensity close to VO2max (95-100%) the duration of 1min intervals is apropriated. In this case, a ratio of 1:1 will adjust well.

Hope it help.

hi Ricardo de Lucas

thanks a lot .

so great

thanks for your good information and tips

hiwa

Hello Hiwa,

some good guidelines from Ricardo. Personally, I am not familiar with any research that can answer your question definitively for weight loss. A meta-analysis from Joyner et al in PLoSONE suggests that 3-5 min intervals may be best to increase VO2max, but I don't know of anything similar for weight loss.

hi Dvid

Thanks a lot again for your new suggestion

I read SEILER and HETLELID ,s article. It was very good

I also suggest " Philippe Meyer et al. 2013. High-Intensity Aerobic Interval Exercise in Chronic Heart Failure.

based of this information I have good resons for work and recovery time, duration and ratio. next step is maching the designed HIIT with a continuous training with 45-50 min in 65-70% Vo2max and select number of intervals and find rational reson for that

best wishes

hiwa

Hi Hiwa

calculate the percentages of the load through the percentages of the VO2 max seems to me to be little accuracy . You can have a VO2 max similar with other subject and your first and second ventilatory threshold be different.

So you can evaluate the first and the second ventilatory threshold and use the 80% of the VO2 max as high- intensity and the two ventilatory threshold as low-intensity.

I suggest this type of workout: 5 minutes at first ventilatory threshold, ten intervales of 2 minutes at second ventilatory threshold and 1 minute at 80% of the VO2 max; 5 minutes at first ventilatory threshold; ten intervales of 2 minutes at second ventilatory threshold and 1 minute at 80% of the VO2 max; and 5 minutes at first ventilatory threshold. Total 46 minutes

Best Regards

José Vilaça

hi José

thank you for your suggestion.

please send me the reference of your suggested protocol for interval training.

I like to design a protocol for research purpose. in our study the traditional continuous aerobic exercise is base protocol but we have some problem with interval training because matching the energy expenditure and time spend between two protocol is important for comparing them. we choose 2 min of 90% and 2 min of 50% that lead to average 70% that is equal to continuous training (Jonathan D. Bartlett et al. 2012. Matched work high-intensity interval and continuous running induce similar ). but number of intervals is a problem. in jonathan et al. study they have same time duration for both protocol but as we know the main preference of interval training is time consuming and we have to avoid of this mistake. may be the energy expenditure or work performed is best way.

best regards

hiwa