Tip of the Month -- Oct. 2005

Power Preparation

By Michael Irr

Postactivation potentiation (PAP) is the phenomenon by which force production in speed movements is enhanced by a previous near maximal lift.  There appears to be two mechanisms for this acute response in the body: 1. phosphorylation of myosin regulatory light chains (biochemical response) or 2. increased motor neuron excitability (neuromuscular response).  For example, prior to performing a plyometric exercise requiring speed, like a box-jump, an athlete would perform a heavy squat (>90% intensity) in order to “enliven” the muscle.  Hopefully, after the squat the athlete would find that he or she could produce more force when they executed the box jump. (Robbins, Bazett)

PAP is a potentially powerful tool that could greatly increase power gains for athletes in training.  Many studies have been performed investigating this phenomenon, producing both positive and mixed results.  The concept seems reasonable and has been exploited for gains in training and research, but more studies need to be done. (Robbins, Bazett)

Many factors may be involved with perfecting the use of this technique.  The time taken between carrying out the squat and box-jump is important.  Time is needed to relieve the fatigue from the near maximal squat, but the athlete cannot wait too long as the PAP effect will wear off.  The optimal time required between the two exercises is unclear, but at least 30 seconds and no more than 4 minutes are recommended. (Robbins)

Studies have also suggested that strength status may play a role in the effect that PAP can have on the upcoming reps.  Two studies showed that athletes with better strength qualities elicited better force production numbers in the speed movements following a near maximal effort.  This implies that a strong foundation of strength may be required to optimally engage the PAP effect. (Robbins)

PAP is the basis for complex training, which is simply the performance of a near maximal exercise followed by a plyometric exercise using the same muscles in hopes of increasing the force production in the muscles during the quick plyometric phase.  Long-term studies on the effects of PAP have not been researched, but studies on complex training have been performed long-term despite the focus not being directly on PAP.  From those studies, significant increases in vertical jump ability were made in the groups that combined strength and plyometric training than in groups that only performed either strength or plyometric training.  (Robins)

Although not complete in its discovery, PAP has to be looked at as a powerful tool in a strength coaches tool box, and when used under the right circumstances, could cause appreciable gains in performance.

Bazett-Jones, David M. et al.  “Effect of Potentiation and Stretching on Maximal Force, Rate of Force Development, and Range of Motion.”  Journal of Strength and Conditioning Research, 2005, 19, 412-426

Robbins, Daniel W.  “Postactivation Potentiation and its Practical Applicability: A Brief Review.”  Journal of Strength and Conditioning Research, 2005, 19, 453-458.