Single vs. Dual Factor Models and Fatigue Accumulation

Single vs. Dual factor model of adaptation
by Mladen Jovanovic

Single factor model of adaptation depicts preparedness (or a single characteristic/ability/trait) as a single line. After the training stimulus, preparedness first decrease, then after some time „supercompensates“ — it returns to normal level and beyond it — thus it is also called „supercompensation“ model. The larger the stimulus, the larger the decrease and thus supercompensation.

I don’t know how the people over time equaled Dual factor model with fatigue accumulation (and provocation of delayed adaptation)!? Dual factor model and fatigue accumulation approach to training to provoce delayed adaptation are NOT SYNONIMS!!! Fatigue accumulation can be also explained by Single factor model too! Fatigue accumulation depends on the stimulus strenght and the frequency.

Fatigue accumulation results in preparedness decrease over starting point, and can be explained by both models. This method is proposed by Verkhoshansky. To be honest, I don’t buy it! Take the sprint for example: your athlete should sprint without being fully recovered between sessions and their performance should decrese over time. And then you unload them and wait for the „miracle“ (long term delayed trainig effect) to come! Again, I don’t buy this approach for training for speed, strenght or power events. Maybe for endurance, but maybe. So, during that „accumulation“ period, your form start to sucks, you are more prone to injury and you are „learning“ to run at poor form. Three words: Avoid this approach!

Dual factor model depicts preparedness as „steady“ component (fitness) and „fast“ component (fatigue). Preparedness at a given instant of time equals fatigue plus fitness levels.

Dual factor model more precisely depicts what is „going on“ and can explain the effect of taper period & unloading while Single factor model can’t — this is because there is allways some minimal fatigue level in athletes wheather or not they tried to train when fully recovered. Thus, there can be increase in preparedness (and thus performance) from training session to training session, while also accumulating some minimal level of fatigue. When we unload or enter taper, fitness component is kept constant and that minimal level of fatigue decreases, and thus preparedness (and thus preformance) jumps even more. This can be depicted by Dual facotor model, while it can’t by Single factor model.

Ok, here is this short article in a nuttshell:

  1. Single & Dual factor models both explain adaptation,altough Dual factor is younger and can explain some things better (like unload & taper effects)
  2. Dual factor model is NOT the synonim with fatigue accumulation approach to training. Fatigue accumulation can be explained by both models
  3. Fatigue accumulation sucks! Preparedness (visible as performance) should go better and not worse over time. Sprinters should run faster, lifters should lift more, jumpers should jump higher/longer over time and not worse over time. Fatigue accumulation is „playing with fire“ — fire is usefull but it can burn!
  4. Do NOT equal Conjugate Sequence System with fatigue accumulation! Training blocks of unidirectional loading are done with elite athletes to provide the adaptation effect while maintaining all other already developed traits. This is a must because they (elites) do not respond very well to sequential approach (one trait at the time) due „Use is or lose it“ law, also, they do not respond well to concurrent approach (all trait at one time), because they cannot respond to larger number of different stimuly (and they get pretty fatigued too)! The solution is to EMPHASISE development of single particular trait while maintaining all neccesary, already developed ones! This doesn’t neccessary mean fatigue accumulation. During that unidirectional loading the performance should go UP instead of down!
  5. Altought the preparedness and thus performance goes UP, the certrain ammount of fatigue is accumulated (but it is pretty low) over time. This is why unloading and taper increse performance before competition. Reduce volume of training allows to decrease fatigue levels while maintaining fitness comonent, the result is increase in performance. This is easily explained by Dual Factor molde, but a little harder with Single factor model
  6. Unloading and taper are not only done to decrease fatigue. Unload is also done to allow various traits/abilities to „synchronize“ because their heterochronic characteristic. Also, it fills C.A.R. or Current Adaptation Reserve which is „depleted“ by preceeding adapatations (which „spends“ it). Unloading allow for „waveing“ progression which is one of the principles of training. You cannot break principle laws, you can only break yourself on them!
  7. I am not creazy, because I spend 4hours to draw this!  I enjoy it! But really, I should get a life!

*** Click on the picture to see full size image!!!