Detraining & Minimal Effective Dose

We were recently directed to a webinar by renowned Exercise Physiologist Trent Stellingwerth from the Canadian Sports Institute (thank you Rachel McCormick from WAIS) titled “Physiology: Detraining and Performance Residuals: Minimal Effective Dose?’. This was timely given the current training limitations most athletes are experiencing around the world and was a great opportunity for us to recap some principles that apply to a runners’ training. We hope this blog can:

  1. help coaches and runners identify what they can do right now (or in the future) to help limit any losses in fitness that they have worked so hard to build and,
  2. set themselves up for a boost in training and performance when a more ‘normal’ training regime can resume.

The full talk is available HERE if anyone is keen to watch, otherwise we have summarised the key points below. As you will notice, most of the points are common sense, however it does provide some interesting numbers and hopefully, some motivation to still get out there and train, even if it’s at a significantly lower level than your ‘normal’.


Aerobic Fitness  

  • Cardiovascular fitness is highly adaptable. Significant changes can occur (both ways) within 5-10 days.
  • Something (even VERY light training), is better than nothing in a recovery phase to limit loss of VO2 Max (how effectively you can use oxygen (O2) for fuel).
  • Aerobic enzymes (that help turn O2 into energy in endurance activity) decline @ ~10%/week with full rest (bed rest), whereas anaerobic enzymes (that help provide energy in VERY high intensity activities) showed very little change with bed rest.
  • The longer period of time someone has been training for, the less severe their loss of fitness.
  • Specific fitness (e.g. your ability to run economically @ 5km race pace or your ability to kick in an 800m) is lost quicker than general fitness (e.g. your capacity to complete a long run).
  • Older and more experienced athletes will take longer to lose the fitness they have built.
  • The rate of loss of adaptation occurs in the following order:
    • Maximal speed (you lose this very quickly)
    • Strength endurance
    • Anaerobic endurance
    • Maximal strength
    • Aerobic endurance
  • The opposite is also true – e.g. aerobic endurance takes a long time to build whereas maximal speed can improve very quickly.


Muscular Strength

  • So long as you reach muscular failure (meaning maximal motor unit recruitment is occurring), you can achieve similar outcomes with high rep/low weight exercises relative to traditional low rep/high weight. This is particularly true for athletes with a low training base in the gym (e.g. distance runners!).
  • Comparable strength adaptations can occur despite varying frequencies, so long as volume is equated. So, for those that may normally lift heavy but now can’t, they could increase frequency of high rep activity to get comparable load and therefore similar benefits.
  • What does research suggest is a minimal effective dose to maintain strength?
    • 1 set of 6-12 reps, 2-3x/week where you go to failure (>9/10 RPE)
  • If you are seeking improvements in power, it’s important to focus on the intent of the lift as this is actually what drives adaptation, not the actual output (i.e. how much intent did you lift with, rather than how quick you moved the bar)
  • Recommendations
    • Lighter weights, lifted to the point of volitional failure work to enhance gains and prevent losses in muscle mass
    • Aim for 3x/sessions per week but increase the volume of work (reps or weight or both) if this is not achievable
    • Have intent during quality work


Interference Effect (combining endurance & strength training)

  • Hypertrophy, strength & power begin to drop away once endurance activities exceed 3x/week & 30min per session. This is why it’s VERY hard for endurance athletes to gain muscle mass from strength training.
  • Resistance training does not affect endurance training as much as endurance training negatively effecting resistance training


Complete time off

  • There is plenty of anecdotal evidence of world class endurance athletes having extended periods of doing nothing and coming back as better athletes. E.g.:
    • Paul Tergat: 20-30 days of complete rest post marathon
    • Female Norwegian XC skiers returning post pregnancy
    • Olympic Swimmer un-retiring after 7y and hitting the A-standard
    • Olympic Rower
      • ~20% reduction from peak fitness after 8w off
      • ~8% reduction from peak fitness after 8w off, then 8w training
      • ~2% improvement from peak fitness after 8w off, then 20w training
    • Editor’s Note: non-weight bearing sports may return to peak physiological fitness quicker after time off then runners due to a runner losing muscular conditioning which is needed to express physiological fitness out on the road (truer the longer your goal event is)


Exercise & Immune Function: Minimal Effective Dose

  • Moderate exercise can boost the immune system where as heavy exercise loads can weaken the immune system:
    • Avoid the high acute loads associated with event specific training
    • Spread training load out with more frequent sessions of low to moderate intensity/volume



There is a lot of information there and hopefully something that can guide you to use your time effectively both now and in the future to achieve your goals. To summarise, the two key themes that emerge are:

  1. SOMETHING is (generally) always better than NOTHING
  2. Try to think of your training in a BROADER context than what you currently are. Whilst you may lose some fitness in the short term (whether forced or not), you can always come back fitter and stronger in the long term if you have a sustainable and progressive routine – and maybe the break will help facilitate that!


Running Regards,

Team Front Runner