This is my first post. I've read all the previous posts in this thread and would firstly like to say thanks to everyone who contributed all the valuable information contained in these posts. A special thanks to all the major contributors, especially Nan Cyclist, Conductor71, and soccertese.

In the early years of this thread, the pioneering work of Jay Alberts and Angela Ridgel was a topic of discussion, in particular their "formula" of keeping cadence between 80 and 90 RPM and heart rate between 60% and 80% of HRmax. Three sessions per week of 40mins duration each session.

What I would like to focus on in this post is one of their more recent papers (May 2013) titled "Variability in cadence during forced cycling predicts motor improvement in individuals with Parkinson's disease". What this paper seems to me to be saying is that the participants who experienced the greatest improvement in motor symptoms were those whose cadence varied the most.

With this in mind, (i.e. in order to get some "variability" into my own exercise bike routine), I have recently adopted an 8s/12s duty cycle. I set the resistance to a fairly low level (I'm currently using the 2nd lowest level on my exercise bike). I pedal very fast for 8 seconds and then pedal slower for 12 seconds. I then repeat 120 times (i.e. a total of 40 mins). My revolution count during the 8 second period averages 14 (i.e. 105 RPM) and my revolution count during the 12 second period averages 16 (i.e. 80 RPM), for an overall average of 90 RPM.

The originator of the 8s/12s duty cycle is Prof. Stephen Boutcher. I learnt about his work from an (Australian) ABC Catalyst program titled "Fit in 6 minutes a week". If you would like to Google it and have a look, the program goes for about 27 minutes and the segment covering his work starts at about the 18:25 mark. Note that his work targets aerobic health and glycemic health (i.e. he is not working in the PD field).

I've only been using the 8s/12s duty cycle for about 2 weeks but the results seem very promising. My symptoms seem to have diminished somewhat and are now more in the background rather then being "front and centre". However, I'm not really sure if an 8s/12s duty cycle matches the Parkinsons researchers criteria for "variability".

Does anyone here have any insights into this issue (i.e. the relative importance of "variability" in the Alberts/Ridgel formula), or can someone point me in the right direction to discover where this issue has been discussed?

Jeff