Active versus passive recovery

Active recovery (or 'warm-down') at the end of an exercise session is popular amongst the sporting community.  The scientific basis for this procedure was probably due to the faster reduction of acidity levels during active versus passive recovery.  Anecdotally we perceive that there is also a perception in the community that passive recovery results in increased muscle stiffness.

Although a higher rate of acid reduction would theoretically be beneficial it is more than outweighed by negative factors such as lower insulin levels, higher catecholamines levels, a further reduction in energy levels, and a delay in feeding.  There is evidence that type II muscle fibers can replenish glycogen stores during active recovery but type I fibres will continue to use up their stores.  Also, it is probably safe to assume that the type II fibres would replenish faster during passive recovery along with feeding.

With regards to muscle stiffness we can offer the following possible explanations.  Passive recovery gets to the recovery state faster than active recovery.  Therefore, the difference between exercise and post-exercise state is more noticeable as the transition is in a shorter time.  The change between states is characterised by a reduction in muscle temperature, reduced blood flow to the muscles, and a change from breaking down glycogen for glycolysis (energy production from carbohydrates) to rebuilding glycogen ready for the next session.  The reduced temperature will result in reduced enzyme activity.  Together these factors mean the muscles change from a performing state to a recovery state.  Any perceptions of stiffness are probably at least partly (if not completely) due to this.  Also, given the pervasiveness of active recovery in sport, there is probably also a psychosomatic cause for any negative perception of passive recovery.

In conclusion, we recommend passive recovery instead of active recovery.

Cramp

Although various causes have been suggested for cramp, the current analysis of research suggests abnormal neuron activity primarily caused by fatigue and activated when a muscle is in a shortened position.  It does not appear to be a fluid or electrolyte related problem.  Whilst a full understanding has yet to emerge we can say that prevention is most easily achieved by reducing fatigue (through improved physical condition, proper nutrition, etc...).  For an immediate relief from cramp, static stretching appears to be effective.  This appears to be due to the stretch dampening the inappropriate neurological activity.  It is currently the only instance where we advise the use of stretching.

Because cramp is activated when the muscle is in a shortened position, passive recovery should be performed with the body in such a shape that muscles that are prone to cramping are lengthened.


On the next page we look at post exercise nutrition.

References

1) POST-EXERCISE MUSCLE GLYCOGEN REPLETION IN THE EXTREME: EFFECT OF FOOD ABSENCE AND ACTIVE RECOVERY, Paul A. Fournier, Timothy J. Fairchild, Luis D. Ferreira and Lambert Bräu, Journal of Sports Science and Medicine (2004) 3, 139-146

2) Skeletal Muscle Cramps During Exercise, Martin P. Schwellnus, THE PHYSICIAN AND SPORTSMEDICINE - VOL 27 - NO. 12 - NOVEMBER 1999