badboy99 and Tupelo3 thank you for correcting my mistake. The 3% figure I gave would only be correct if all the participants were totally disabled by PD. This was not the case.
My mistake raises yet again the importance of metrics. They need to be accurate. They need to be understandable. They need to communicate to the extent that they inform action.
Put to one side, for now, statistical factors, the degree of blindedness of the trial, the subjective nature of some of the assessments, the placebo effect and all other confounding factors. Take the results as given. On that basis we should be able to make an informed answer to the question: Should we start this form of exercise today?
Unfortunately, the original paper is behind a pay wall, but the abstract is available and this gives some clues as to the size of the therapy's benefit. In it Kelly et al. write [1]:
"... Fifteen participants with PD (Hoehn & Yahr stage 2-3) completed 16 wk of high-intensity exercise training designed to simultaneously challenge strength, power, endurance, balance, and mobility function. ... These adaptations were accompanied by a host of functional and clinical improvements (p<0.05): total body strength (+30-56%); leg power (+42%); single leg balance (+34%); sit-to-stand motor unit activation requirement (-30%); 6-min walk (+43m), Parkinson's Disease Quality of Life Scale (PDQ-39, -7.8pts); Unified Parkinson's Disease Rating Scale (UPDRS) total (-5.7pts) and motor (-2.7pts); and fatigue severity (-17%). ..."
The measure that I find it easiest to get to grips with is the "6-min walk (+43m)". This would represent about a 6% improvement for me. But my walking is very good, so you can't take this as representative for all PwP. It's a pity that they don't give side-to-side tap test results which would give an indication of upper body mobility.
It should be pointed out that since the disease is progressive, without intervention one would have expected things to have got worse over the 16 weeks of the study. Thus, the true size of the benefit is higher than the raw figure.
I'm convinced of the benefit of exercise for PwP. The important thing is that we can measure its impact on PD in such a way that we can optimise its effectiveness.
References:
[1] "NOVEL, HIGH-INTENSITY EXERCISE PRESCRIPTION IMPROVES MUSCLE MASS, MITOCHONDRIAL FUNCTION, AND PHYSICAL CAPACITY IN INDIVIDUALS WITH PARKINSON'S DISEASE"
Neil A. Kelly1, Matthew P. Ford1, David G. Standaert1, Ray L. Watts1, C. Scott Bickel2, Douglas R. Moellering1, Steven Craig Tuggle2, Jeri Y. Williams3,Laura Lieb1, Samuel T. Windham2, and Marcas M. Bamman1,*
Journal of Applied Physiology, January 9, 2014
http://jap.physiology.org/content/ea....2013.abstract
John