Potentiation involves the creation of a set of stimulatory circumstances within the muscle firing complex that boost neural excitation, motor unit and muscle fibre recruitment and reduce inhibition. Lifting weights before a plyometric workout (complex training) has been shown to enhance the performance of the plyometric activity. However, any potentiating activity must not fatigue the CNS otherwise the reverse effect will be experienced."
"Heart rate variations for a given intensity
A reduction in heart rate for a given intensity is usually due to an improvement in fitness but a number of other factors might explain why heart rates can vary for a given intensity:
Dehydration can increase the heart rate by up to 7.5%
Heat and humidity can increase the heart rate by 10 beats/minute
Altitude can increase the heart rate by 10 to 20%, even when acclimatised
Biological variation can mean the heart rate varies from day to day by 2 to 4 beats/minute"