A study of cyclists by the University of Stirling may have uncovered the secret to getting fitter faster.
Researchers put 12 cyclists through a 29-week trial to determine the optimum training intensity.
They split the cyclists into two groups. One pedalled at low intensity for 80% of the time and at high for 20%, while the other group had a more moderate regime.
The high and low intensity sessions saw a greater improvement in fitness.
Health and exercise scientists from Scotland's University for Sporting Excellence assigned six cyclists to a block of 80% low and 20% high intensity training.
The second group of six pedalled at 55% low and 45% moderate intensity.
Quantity vs quality
After a four-week rest period, the groups then switched over and the results showed the block combining high and low intensity exercise sessions increased both power and performance twice as much as the block with low and moderate intensity training.
Dr Stuart Galloway, who led the study, said: "Quantity and quality of training has provided a quandary for coaches and athletes for many years, but this study is the first of its kind to provide an answer to the problem.
"It is a case of training smarter. We found in these cyclists that if you can make the hard sessions harder and the easy sessions easier then you will likely see better progress.
"Amateur athletes tend to spend a lot of their training in a moderate intensity bracket, which in our study showed much smaller improvements.
"For the wider public, most people were advised to do moderate-level intensity exercise for around three hours a week. Then, more recently, high intensity bouts of exercise, such as spin cycling classes or interval running, have been presented as the best option.
"We would suggest that, while high intensity is still important, it's the combination with low intensity which has the biggest impact."
This combination is also beneficial when it comes to aiding recovery, a vital component in improving physical health.
Dr Angus Hunter, senior lecturer in exercise physiology and co-author on the study, said: "Muscle fatigue can be detrimental to a successful long-term exercise programme, but our study suggests that a much quicker recovery occurs when adopting the low and high intensity combination.
"Your muscles may be fatigued more quickly when you work at a high intensity, but they recover more quickly too.
"We understand that, for an athlete, their training intensity will vary depending on whether they are building towards a competition or in the off-season, but this study offers a good model to enable you to hit your peak."