Although the focus of the current (N = 250) CYCLE-II trial is on high-intensity aerobic exercise, research is still proceeding in the area of "forced exercise", both at the Cleveland Clinic [1] and at KSU [2]. A couple of review articles on this topic have also been published (fairly) recently [3, 4].

[1] Forced, Not Voluntary, Aerobic Exercise Enhances Motor Recovery in Persons With Chronic Stroke, Susan M Linder et al. (2019).
Forced, Not Voluntary, Aerobic Exercise Enhances Motor Recovery in Persons With Chronic Stroke - PubMed

[2] Optimization Of A SMART Dynamic Bike To Improve Motor Function In Parkinson’s Disease, Angela L Ridgel et al. (2021).
Optimization Of A SMART Dynamic Bike To Improve Motor Functi... : Medicine & Science in Sports & Exercise
(poster only, at this stage)

[3] Review of studies considering the effect of forced exercise on symptoms of Parkinson's disease, William J Kohler (2019).
Review of studies considering the effect of forced exercise on symptoms of Parkinson's disease. - Document - Gale OneFile: Health and Medicine
(abstract only - the rest is behind a paywall)

[4] Therapeutic effects of forced exercise cycling in individuals with Parkinson's disease, Daniel G Miner et al. (2020).
Therapeutic effects of forced exercise cycling in individuals with Parkinson's disease - PubMed
(abstract only - the rest is behind a paywall)