Current evidence and practical applications of flywheel eccentric overload exercises as post-activation potentiation protocols: a brief review

Purpose 
To summarize the evidence on postactivation potentiation (PAP) protocols using flywheel eccentric overload (EOL) exercises. 
Methods 
Studies were searched using the electronic databases PubMed, Scopus, and Institute for Scientific Information Web of Knowledge.
Results 
In total, 7 eligible studies were identified based on the following results: First, practitioners can use different inertia intensities (eg, 0.03–0.88 kg·m2), based on the exercise selected, to enhance sport-specific performance. Second, the PAP time window following EOL exercise seems to be consistent with traditional PAP literature, where acute fatigue is dominant in the early part of the recovery period (eg, 30 s), and PAP is dominant in the second part (eg, 3 and 6 min). Third, as EOL exercises require large force and power outputs, a volume of 3 sets with the conditioning activity (eg, half-squat or lunge) seems to be a sensible approach. This could reduce the transitory muscle fatigue and thereby allow for a stronger potentiation effect compared with larger exercise volumes. Fourth, athletes should gain experience by performing EOL exercises before using the tool as part of a PAP protocol (3 or 4 sessions of familiarization). Finally, the dimensions of common flywheel devices offer useful and practical solutions to induce PAP effects outside of normal training environments and prior to competitions. 
Conclusions 
EOL exercise can be used to stimulate PAP responses to obtain performance advantages in various sports. However, future research is needed to determine which EOL exercise modalities among intensity, volume, and rest intervals optimally induce the PAP phenomenon and facilitate transfer effects on athletic performances.