Experimental model of pain-free treadmill training in patients with claudication. 2005

Abstract
OBJECTIVE:
Treadmill training in claudication is often based on walking exercise to a pain threshold or longer to the maximum muscle pain of the lower limbs.  This kind of exercise may cause an inflammatory response. The purpose of this study was to determine whether pain-free treadmill training using walking exercise to 85% of the distance to onset of claudication pain can significantly improve pain-free walking distance in patients with intermittent claudication and to evaluate whether this kind of program may induce an inflammatory response leading to the progression of atherosclerosis.
DESIGN:
A total of 98 patients aged 50-70 yrs with stable intermittent claudication were randomized into a supervised treadmill training program or a comparison group.  Patients in the treatment group participated in 12 wks of supervised treadmill training.  We examined the effects of 12 wks of pain-free treadmill training on pain-free walking distance, total leukocyte count, neutrophil count, and microalbuminuria in patients with claudication.
RESULTS:
A total of 80 participants completed the program.  Exercise rehabilitation increased the time to onset of claudication pain by 119.2%, from 87.4 +/- 38 m to 191.6 +/- 94.8 m (P < 0.001).  There was no increase in total leukocyte count, neutrophil count, or microalbuminuria after 12 wks of treadmill exercise (P > 0.05)
CONCLUSION:
A pain-free training program can be used in the treatment of claudication as a low-risk program, increasing walking ability without potential harmful effects of ischemia-reperfusion injury.

My comments:

Most of the papers I have discussed earlier encouraged walking to various points of pain to treat intermittent claudication. The idea was that the pain brought on was a stress needed to force increased blood flow to the lower extremities which would later improve total and pain free walking distance.

The protocol used here was to have patients walk at 2 mph at a 12 degree grade and find out the distance that pain comes on. Then patients would do the same, but only go to 85% of that distance, rest ~2 minutes and do it again for a total of 3 times in a session. Training was performed 3 times per week for 12 weeks. Pain free walking distance (PFWD) was recalibrated once at 6 weeks. PFWD improved 119%, while total distance and speed (beyond the 2 mph) were not measured.

• PFWD increase per week = 9.92%
• PFWD increase per workout = 3.31%

Improvements look reasonably good and indicate that pain free walking has benefits, and not much less than some programs where patients did walk to a degree of pain.  This program might be idea for patients who might have a lesser tolerance for pain. Interestingly the interval treadmill protocol with active rest is holding strong in first place with results per week and per workout.