The Importance of Neural Factors in Strength Performance
The capacity to exercise strength in a short period of time, known as the rate of strength development, is one of the main performance indicators in explosive actions.
It is important to assure a correct recovery between training sessions and even between the different exercises of the same session to maximize adaptations to training. There are different recovery methods, from cold therapy or massages to others, such as wearing compression garments, pressotherapy, or electrostimulation. However, even though there are a variety of methods, the most common one is to perform low-intensity exercises (known as “active recovery”).
Despite the popularity of active recovery, there is still certain controversy as to whether resting after an exercise session is more effective or whether a “regenerative” low-intensity exercise session is appropriate. According to a survey among French professional football teams, 81 % of them use low-intensity exercises during 15- 30 minutes as a recovery method right after a game or the days after it.1 One of the main reasons to implement active recovery compared to passive recovery, is that it helps stimulate blood flow through the muscles. This has been shown to speed up the elimination of metabolites, such as lactate.2 However, the evidence is starting to suggest that the elimination of lactate per se should not be considered as a sign or marker for a better recovery, because lactate does not cause fatigue as it was thought a long time ago.3 It has also been observed that active recovery after an exercise session could worsen glycogen synthesis, especially in slow or type I fibres (the ones used during low-intensity exercise).4 In fact, several studies performed in footballers who played two matches separated by 3 days have not shown benefits in several recovery markers (including performance, damage and muscle pain, and inflammation markers) when comparing the active recovery (1 hour of low-intensity exercise) to passive recovery.5–7 It is important to mention that a recent meta-analysis concluded that active recovery is effective to reduce muscle pain after exercise sessions, although it also concluded that this method does not reduce significantly the fatigue perception or produce benefits in muscle damage (Creatine Kinase) or inflammatory (C reactive protein and interleukin 6) markers.8 Therefore, scientific evidence is not strong enough to back up unanimously the effectiveness of active recovery after an intense exercise session or a game compared to resting. Therefore, it will depend on personal preferences which recovery strategy to implement.
There is also controversy regarding the benefits of active recovery compared to rest during pauses within the same exercise session. In regard to this, several studies have shown that active recovery between high-intensity exercises complicates muscle reoxygenation, and it even diminishes performance, possibly due to the fact that less muscle reoxygenation complicates the phosphocreatine resynthesis. A study led by Gregory Dupont, scientist and physical trainer for teams like Real Madrid or the French national football team, showed that the active low-intensity recovery between two sprints of 15 and 30 seconds reduced the performance in the second sprint.9 Similarly, another study assessed the effect of active or passive recoveries of different duration between 10 sprints for 5 seconds. The results showed that when recoveries are short (especially for less than a minute), active recovery would diminish performance in sprints and muscle reoxygenation.10 Another study led by Martin Buchheit, performance manager at Paris Saint Germain and who will take part in Performance in Sports Tomorrow, evaluated the effect of active or passive recovery during 21 seconds between 6 sprints of 4 seconds. Again, the results showed a decrease in performance with an active recovery strategy, as well as higher levels of muscle deoxygenation, oxygen consumption and lactate.11
It is important to mention that, on some occasions, the goal can be to maintain the high metabolic stress during the session, but not so much to promote recovery. Thus, for example, in a high-intensity interval training session aimed at improving the maximum oxygen consumption, the objective can be to maximise the time in which the athlete is training at such intensity.12 That is why, in some cases (especially when extending recovery periods approximately over 3 minutes) performing an active recovery at low-intensity between exercise series can help maintain the kinetics of high oxygen, and thus increase the time in which the maximum consumption of oxygen is maintained, although it is important to take into account the fatigue produced, and therefore, the possible decrease of performance in the series.12
To sum up, despite its popularity, there is not enough evidence that unanimously supports the benefits of active recovery after an intense training session or a game. When recovering actively between efforts within the same training session, performance may decrease, especially for high-intensity short exercises (for example, sprints) and if recoveries are short. However, active recovery can bring certain psychological benefits, and help increase the metabolic stress during the exercise sessions to maximise the adaptations to training.
Pedro L. Valenzuela