Endurance and strength training have different benefits for people with peripheral arterial disease, but both improve quality of life

Abstract

Question

Do treadmill training and resistance training improve the functional performance of patients with peripheral arterial disease (PAD)?

Design

Randomised, controlled trial with blinded outcome assessment and stratification for symptoms of intermittent claudication (IC).

Setting

Tertiary hospital in the USA.

Participants

Participants with an ankle brachial index of 0.95 or less were recruited from vascular clinics and the community. Key exclusion criteria were critical limb ischaemia, foot ulcers, amputation, inability to attend or perform the interventions, and usual exercise comparable to the study regimens. Randomisation of 156 participants allotted 51 to treadmill training, 52 to resistance training and 53 to a control group.

Interventions

The treadmill group performed supervised treadmill exercise 3 times per week for 6 months. Participants aimed to increase to 40 minutes by week 8, after which the speed or grade of the treadmill was progressed. Participants with IC were encouraged to exercise to near maximal leg symptoms. Asymptomatic participants exercised at a perceived exertion of 12 to 14 on the Borg scale. The resistance group also performed supervised exercise 3 times per week for 6 months, including 3 sets of 8 repetitions of resisted lower limb exercises. External resistance was maintained above 50% of 1 repetition maximum and perceived exertion at 12 to 14. The control group attended 11 sessions that were designed to provide contact with a health professional but not to change behaviour.

Outcome measures

The primary outcomes were the change in the six-minute walk test (6MWT) and the short physical performance battery (SPPB) at 6 months. The SPPB assesses walking speed, balance, and sit-to-stand performance. Secondary outcome measures were treadmill endurance, lower limb strength, endothelial function measured non-invasively at the brachial artery, habitual physical activity measured over 7 days via an accelerometer, a walking impairment questionnaire (WIQ), and the SF-36 quality of life questionnaire.

Results

Compared to control, treadmill training significantly improved 6MW distance (by 36 m, 95% CI 15 to 57), total treadmill time (by 3.4 min, 95% CI 2 to 4.8), pain-free treadmill time (by 1.6 min, 95% CI 0.3 to 2.9), endothelial function, and the Distance domain of the WIQ. Compared to control, resistance training significantly improved total treadmill time (by 1.9 min, 95% CI 0.5 to 3.3), knee extension strength (by 80 N, 95% CI 37 to 124), and the Distance and Stair Climbing domains of the WIQ. Both regimens produced significant, 7.5-point improvements in the Physical Functioning domain of the SF-36.

Conclusion

Treadmill and resistance training have different benefits for people with peripheral arterial disease, but both improve quality of life.