SIT vs ET

endswell

can someone explain this a bit more? is it basically saying that 200m reps are better than mile reps etc?

www.ncbi.nlm.nih.gov/m/pubmed/20473222/


sprint interval training improves aerobic performance but not maximal cardiac output.

Authors
Macpherson RE, et al.

Med Sci Sports Exerc. 2011 Jan;43(1):115-22.
Affiliation

Exercise Nutrition Research Laboratory, Faculty of Health Sciences, School of Kinesiology, The University of Western Ontario, London, Canada.


Abstract

Repeated maximal-intensity short-duration exercise (sprint interval training, SIT) can produce muscle adaptations similar to endurance training (ET) despite a much reduced training volume. However, most SIT data use cycling, and little is known about its effects on body composition or maximal cardiac output (Qmax).

PURPOSE: The purpose of this study was to assess body composition, 2000-m run time trial, VO(2max), and Q(max) effects of run SIT versus ET.

METHODS: Men and women (n = 10 per group; mean ± SD: age = 24 ± 3 yr) trained three times per week for 6 wk with SIT, 30-s all-out run sprints (manually driven treadmill), four to six bouts per session, 4-min recovery per bout, versus ET, 65% VO(2max) for 30 to 60 min·d(-1).

RESULTS: Training improved (P < 0.05) body composition, 2000-m run time trial performance, and VO(2max) in both groups. Fat mass decreased 12.4% with SIT (mean ± SEM; 13.7 ± 1.6 to 12.0 ± 1.6 kg) and 5.8% with ET (13.9 ± 1.7 to 13.1 ± 1.6 kg). Lean mass increased 1% in both groups. Time trial performance improved 4.6% with SIT (-25.6 ± 8.1 s) and 5.9% with ET (-31.9 ± 6.3 s). VO(2max) increased 11.5% with SIT (46.8 ± 1.6 to 52.2 ± 2.0 mL·kg·(-1)·min(-1)) and 12.5% with ET (44.0 ± 2.0 to 49.5 ± 2.6 mL·kg·(-1)·min(-1)). None of these improvements differed between groups. In contrast, Q(max) increased by 9.5% with ET only (22.2 ± 2.0 to 24.3 ± 1.6 L·min(-1)).

CONCLUSIONS: Despite a fraction of the time commitment, run SIT induces similar body composition, VO(2max), and performance adaptations as ET, but with no effect on Q(max). These data suggest that adaptations with ET are of central origin primarily, whereas those with SIT are more peripheral

Pherekydes

endswell wrote: »

can someone explain this a bit more? is it basically saying that 200m reps are better than mile reps etc?

No. It's saying that you can achieve the same performance and body composition improvements with SIT compared to ET for a fraction of the time commitment. SIT seems to have no discernable impact on maximal cardiac output, while ET improves Qmax by nearly 10%. The sample size is relatively small, so one would need to be careful drawing conclusions.

Raighne

endswell wrote: »

can someone explain this a bit more? is it basically saying that 200m reps are better than mile reps etc?

www.ncbi.nlm.nih.gov/m/pubmed/20473222/


sprint interval training improves aerobic performance but not maximal cardiac output.

Authors
Macpherson RE, et al.

Med Sci Sports Exerc. 2011 Jan;43(1):115-22.
Affiliation

Exercise Nutrition Research Laboratory, Faculty of Health Sciences, School of Kinesiology, The University of Western Ontario, London, Canada.


Abstract

Repeated maximal-intensity short-duration exercise (sprint interval training, SIT) can produce muscle adaptations similar to endurance training (ET) despite a much reduced training volume. However, most SIT data use cycling, and little is known about its effects on body composition or maximal cardiac output (Qmax).

PURPOSE: The purpose of this study was to assess body composition, 2000-m run time trial, VO(2max), and Q(max) effects of run SIT versus ET.

METHODS: Men and women (n = 10 per group; mean ± SD: age = 24 ± 3 yr) trained three times per week for 6 wk with SIT, 30-s all-out run sprints (manually driven treadmill), four to six bouts per session, 4-min recovery per bout, versus ET, 65% VO(2max) for 30 to 60 min·d(-1).

RESULTS: Training improved (P < 0.05) body composition, 2000-m run time trial performance, and VO(2max) in both groups. Fat mass decreased 12.4% with SIT (mean ± SEM; 13.7 ± 1.6 to 12.0 ± 1.6 kg) and 5.8% with ET (13.9 ± 1.7 to 13.1 ± 1.6 kg). Lean mass increased 1% in both groups. Time trial performance improved 4.6% with SIT (-25.6 ± 8.1 s) and 5.9% with ET (-31.9 ± 6.3 s). VO(2max) increased 11.5% with SIT (46.8 ± 1.6 to 52.2 ± 2.0 mL·kg·(-1)·min(-1)) and 12.5% with ET (44.0 ± 2.0 to 49.5 ± 2.6 mL·kg·(-1)·min(-1)). None of these improvements differed between groups. In contrast, Q(max) increased by 9.5% with ET only (22.2 ± 2.0 to 24.3 ± 1.6 L·min(-1)).

CONCLUSIONS: Despite a fraction of the time commitment, run SIT induces similar body composition, VO(2max), and performance adaptations as ET, but with no effect on Q(max). These data suggest that adaptations with ET are of central origin primarily, whereas those with SIT are more peripheral

There's nothing useful for endurance training to be learnt from studies like these. A classic problem is that high intensity work always shows some improvement within a short space of time, lower intensity work also does, but not to the same extent. Over longitudinal studies this trend reverses markedly

The researchers cannot handle all the variables in play here: we know that sprint training does not stimulate the endurance fibres but we also know that simply doing physical activity, as opposed to not doing it, will improve your ability to move (for neuromuscular reasons primarily) - but this has nothing to do with muscle fibres per se, so the whole premise of the study is flawed because the researchers cannot isolate the variable they are looking for.

My question would be exactly what the researchers are trying to achieve here: did they expect to find that doing some sprints would potentially make you an good long-distance athlete?

What the studies concludes is well-known anyway and has been for decades -sprint training is primarily stimulating neuromuscular factors and training the huge Type 2B muscle fibres. 65% VO2max work is aerobic and thus does put in place a much more fundamental infrastructure for long term running success: capillary density, heart muscle endurance, mitochondrial density etc. etc.

Finally, the "endurance trained group" (the protocol here scarce justifies the term) actually improved more in the 2000m time trial and in VO2max. If they had put in place a realistic study with more normal training volumes and monitored it over say, 1 year, this gap would be a chasm.

Don't get derailed by studies such as these: treat them as a curiosity but look back to the methods that have always worked where it really matters - victory in major competition, and learn how to apply those to your current level of fitness and life circumstances.

Kurt Godel

Pherekydes wrote: »

The sample size is relatively small, so one would need to be careful drawing conclusions.

+1

Anyone who wants to try a course in biostatistics, Harvard are offering a free online course in methods. Enroll ASAP https://www.edx.org/courses

endswell

Thanks all. I was actually looking for something on how long it takes for a training session to take effect and came across this. Interested in some of the science behind running so if you have any reading material please post, Tks.

dna_leri

In any of these studies you do have to look at the details.
Are these trained or untrained individuals? (Can't tell from the abstract)
What was the duration of the training? (6 weeks)
Did they all complete the training or did any get injured? (don't know)
Do you want to get faster or lose fat? (different groups get different results)

There is a place for high intensity interval training, you just have to find the appropriate place for you. One point I try to remember is "metabolic fitness precedes structural readiness" - see here for more.

For more on the usefulness of interval training - see here.