Strength training increases walking tolerance in intermittent claudication patients: randomized trial. J Vasc Surg. 2010 Jan;51(1):89-95. Ritti-Dias RM, Wolosker N, de Moraes Forjaz CL, Carvalho CR, Cucato GG, Leão PP, de Fátima Nunes Marucci M.
To analyze the effects of strength training (ST) in walking capacity in patients with intermittent claudication (IC) compared with walking training (WT) effects.
Thirty patients with IC were randomized into ST and WT. Both groups trained twice a week for 12 weeks at the same rate of perceived exertion. ST consisted of three sets of 10 repetitions of whole body exercises. WT consisted of 15 bouts of 2-minute walking. Before and after the training program walking capacity, peak VO(2), VO(2) at the first stage of treadmill test, ankle brachial index, ischemic window, and knee extension strength were measured.
ST improved initial claudication distance (358 +/- 224 vs 504 +/- 276 meters; P < .01), total walking distance (618 +/- 282 to 775 +/- 334 meters; P < .01), VO(2) at the first stage of treadmill test (9.7 +/- 2.6 vs 8.1 +/- 1.7 mL.kg(-1).minute; P < .01), ischemic window (0.81 +/- 1.16 vs 0.43 +/- 0.47 mm Hg minute meters(-1); P = .04), and knee extension strength (19 +/- 9 vs 21 +/- 8 kg and 21 +/- 9 vs 23 +/- 9; P < .01). Strength increases correlated with the increase in initial claudication distance (r = 0.64; P = .01) and with the decrease in VO(2) measured at the first stage of the treadmill test (r = -0.52; P = .04 and r = -0.55; P = .03). Adaptations following ST were similar to the ones observed after WT; however, patients reported lower pain during ST than WT (P < .01).
ST improves functional limitation similarly to WT but it produces lower pain, suggesting that this type of exercise could be useful and should be considered in patients with IC.
If you just read the abstract you would come away from this study with the impression that strength training is just as good as treadmill training for intermittent claudication.
The weight training group used an 8 machine exercise protocol based working the total body 3 sets of 10 reps each which is fine enough. However both the weight training program, and the walking program (2 minutes on, 2 minutes off, for 60 minutes, attempting to get claudication the last 30 seconds of each interval), which to me sounds a bit dubious and not optimal for either. In both groups they wanted 60 minutes of total workout time, with 30 minutes of that time being rest in both groups and exercise was done 2 days per week for 12 weeks. While both groups improved neither group improved that much on a percent basis. Pain free walking distance (PFWD) improved 41% in the strength group and 37% in the treadmill group, while maximum walking distance (MWD) improved 25% in the strength group and 37% in the treadmill group. If I do the match per week and per workout improvements were as follows:
- Strength PFWD/week = 3.4%
- Strength MWD/week =2.1%
- Strength PFWD/workout = 1.7%
- Strength MWD/workout = 1.0%
- Treadmill PFWD/week = 3.1%
- Treadmill MWD/week = 3.1%
- Treadmill PFWD/workout = 1.5%
- Treadmill MWD/workout = 1.5%
So neither the strength nor treadmill increases in walking distance were anything close to the improvements seen in either conventional walk/passive rest or walk/active rest protocols of other studies. Also I don’t think it was a great idea for the authors to try and equate effort between strength and treadmill programs and they would have done better to just use the best strength training program they could (with intensity based on repetition maximums) and compared that to the best walking program, rather than make up their own for each. Still I think it’s good that they found strength training did help improve walking distance and for patients with peripheral neuropathy who are particularly weak I think it would be an especially important part of their treatment. Also this study noted that the strength training group had 50% less pain, which sounds great, but when you look at the specific data that meant pain during exercise was a 1.5/10 during strength training vs. 3/10 during treadmill training, which isn’t of that much practical significance.
As always, if you have any further questions or need for clarifications, please don’t hesitate to ask. Being aware that some of my blog ideas are contentious and occasionally a bit out of the field of my expertise, I encourage my readers to come forth with any questions/comments that are of interest or concern. Your comments are valued and welcomed.
Chad Reilly is a licensed physical therapist, located in North Phoenix, practicing science based medicine with treatment protocols unique and effective enough to proudly serve patients from Phoenix, Scottsdale, Mesa, Chandler, Tempe, Peoria, and Glendale.