Strength Training in Walking Tolerance in Intermittent Claudication Patients

Background: Muscle atrophy and reduced leg strength are related to exercise intolerance in patients with intermittent claudication (IC), suggesting that strength training (ST) could improve exercise performance in these patients.

Objective: Analyze the effects of ST in walking capacity in patients with IC comparing with walking training (WT) effects.

Intervention: Patients 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 3 sets of 10 repetitions of whole body exercises. WT consisted of 15 two-minute bouts of walking intercalated with 2 minutes of resting.

Measurements: Walking capacity, peak VO2, walking economy, ankle brachial index, ischemic window and knee extension strength

From July 2005 to December 2006, three hundred patients with peripheral arterial disease, who were enrolled in a tertiary center specialized in vascular disease and were able to walk for at least 2 minutes at 2 miles per hour, were invited to a meeting at which explanations about this study were given. 80 patients attended the meeting, 60 of them decided to take part of the study, and 52 attended for the screening tests.

Patients were included in the study if they met the following criteria: Fontaine stage II peripheral arterial disease, symptoms of IC for at least 6 months, ankle/brachial index (ABI) at rest ≤ 0.90 in 1 or 2 legs, reduction of ABI after treadmill test, and exercise tolerance limited by IC. Patients were excluded under the following conditions: presence of chronic lung disease, inability to obtain ABI measurement due to noncompressible vessels, exercise tolerance limited by factors other than claudication (eg, dyspnea or orthopedic problems), poorly controlled blood pressure, presence of electrocardiogram response suggestive of myocardial ischemia during the exercise test, and history of revascularization in the previous year.

Procedures Patients were randomly (by drawing lots) divided into 2 groups: strength (ST, n = 17) and walking (WT, n = 17) training. They were evaluated at baseline (pre-training) and after 12 weeks of exercise training (post-training). During evaluations were assessed exercise tolerance and strength.

Both training programs (ST and WT) were supervised, conducted twice a week, lasted for 12 weeks, and started after a 2-week preconditioning-orientation phase. In both programs, rate of perceived exertion during exercise was kept similar and between 11 to 13 on the15-grade Borg scale. Furthermore, the duration of exercise sessions was prescribed as 30 min of exercise for ST and WT groups.

Eligibility Criteria:
Inclusion Criteria:

* Fontaine stage II peripheral arterial disease(14)
* Symptoms of intermittent claudication for at least 6 months
* Ankle/brachial index (ABI) at rest ≤ 0.90 in 1 or 2 legs
* Reduction of ABI after treadmill test
* Exercise tolerance limited by intermittent claudication

Exclusion Criteria:

* Presence of chronic lung disease
* Inability to obtain ABI measurement due to noncompressible vessels
* Exercise tolerance limited by factors other than claudication (e.g., dyspnea or orthopedic problems)
* Poorly controlled blood pressure
* Presence of electrocardiogram response suggestive of myocardial ischemia during the exercise test
* History of revascularization in the previous year