Recovery From HIIT: Know Your Muscle Type
Last time we discussed the different muscle fibre typology of world-class cyclists in different disciplines. Now let’s explore how different muscle typology can affect recovery from high-intensity interval training.
Track sprinters were at one end of the spectrum with high proportions of fast-twitch muscles
In my last article, we discussed a Belgian/Australian collaboration using non-invasive imaging techniques to determine the relative muscle fibre typology of world-class cyclists across disciplines (Lievens et al. 2020a). We saw that BMX and track sprinters were at one end of the spectrum with high proportions of fast-twitch muscles. Road climbers were at the opposite end with high slow-twitch composition.
Overall, world-level performance seems to select for a very race-specific type of athlete. You’ve no doubt seen this in action in your own circle of fellow cyclists and competitors. But beyond academic interest, how might our individual typology affect our training response?
Recovery From HIIT
In the first of two companion studies from the same collaboration, the impact of muscle fibre typology on recovery from high-intensity interval training was explored (Lievens et al. 2020b). If a cyclist has higher proportion of fast-twitch fibres, which are capable of high force but fatigue rapidly, might it also mean that their recovery from a hard training session take longer than a cyclist with more slow-twitch fibres?
- From a larger group of 32 initial participants, 10 trained cyclists with high FT typing and 10 with high ST typing were recruited.
- Each group performed 3×30 s Wingate sprints. A single 30 s Wingate is nasty. Rather than winding up to peak power, you start spun out at max power, then hang on for dear life. So 3 of these, done with 4 min rest, are just nasty.
- Over the 5 h following this workout, each athlete performed repeated muscle testing. This included maximal isometric (leg stays in same position) knee extension. Isometric maximal force is also higher than when the joint moves. Also, muscle force from maximal electric stimulation was tested.
The expected results were seen from the Wingates themselves. The FT group had higher peak power during the first sprint. However, the rate of fatigue was faster in this group over both an individual Wingate sprint, and over the course of the three Wingates. Overall mean power output over the three Wingates were similar for both groups.
Importantly, the ST and FT groups were dramatically different in how they recovered over the course of 5 hours following this workout. In the ST group, there was a slight decrease in maximal knee extension torque at 10 min into recovery (~95% of baseline), but this recovered to pre-workout levels by 20 min.
In contrast, the FT group had a much greater torque reduction at 10 min (~75% of baseline), and torque was still significantly lower than pre-workout levels even 5 h into recovery.
With age it takes us more days in between before we’re really ready for another hard effort
Dosing Your Efforts
We have all likely heard of, or are experiencing, the fact that one of the biggest challenges for masters athletes is the difficulty in recovering from hard efforts. While we can still smash out hard training, with age it takes us more days in between before we’re really ready for another hard effort.
The caveat with this study is that it only looked at the 5 h following a single workout, and testing wasn’t done in the days following. However, a study like this really highlights the importance, regardless of age, of individualizing your recovery within your training. Besides age, it may be that sprinter types of athletes may also require more recovery between breakthrough workouts.
These types of athletes would also likely really benefit from a highly polarized training program, with the low-intensity training really giving the body the best chance of recovering in between breakthrough efforts. In contrast, ST athletes may be the ones who respond better to sustained threshold or sweetspot-type training due to their relatively faster recovery between efforts.
Determining Athlete Type
Barring access to indirect or direct muscle fibre typing, how do you determine your athlete type? One way is using software like Xert, which determines your fitness signature based on Peak Power (PP) and High Intensity Energy (HIE) along with Threshold Power (TP). If you have a very high PP (1 s power) or HIE (analogous to anaerobic work capacity), then it is likely that you have a relatively high proportion of FT muscle.
Other software can give you similar insights to your capabilities and from there your likely rough bracket of muscle type. Barring software, if you’re an experienced rider and racer, you likely know what style of racing you prefer or tend to do better at, and the infographic from my previous article can again put you into your likely muscle type bucket.
Sprinters and climbers – Fast and slow-twitch fibres
The main takeaway from this study is that the exact same workout can have drastically different impact on two riders because of their athlete types. Where this becomes especially important is that the same workout can cause much greater depth of acute and long-term fatigue in fast-twitch dominant riders, and this requirement for longer recovery must be accommodated within training.
Next time, we’ll finish this series by looking at the impact of muscle fibre typology on the risks for overtraining from sudden increases in training load.
Ride fast and have fun!
Lievens E, Bellinger P, Van Vossel K, et al (2020a) Muscle Typology of World-Class Cyclists across Various Disciplines and Events. Med Sci Sports Exerc Publish Ahead of Print: https://doi.org/10.1249/MSS.0000000000002518
Lievens E, Klass M, Bex T, Derave W (2020b) Muscle fiber typology substantially influences time to recover from high-intensity exercise. J Appl Physiol 128:648–659. https://doi.org/10.1152/japplphysiol.00636.2019