By Jon Stavres MS, ACSM-EP-C
There is a lot of research that outline the many benefits of exercise for people with cardiovascular disease. From improvements in exercise tolerance to reducing blood pressure, exercise is a well-accepted method for prevention, treatment, and rehabilitation from cardiovascular disease. There are many factors that contribute to these benefits. Some of these are central factors (i.e. the central nervous system or the heart), while others are due to adaptations of the muscle and local blood flow.
When a person exercises, their muscles will adapt to become more efficient. These muscular adaptations can improve the ability to pull oxygen from the blood, produce force, and even recover from exercise; all of which would greatly benefit someone with cardiovascular disease. Recent research evidence suggests that single limb exercises may have an added benefit related to muscular adaptations.
Researchers, Burns et al., conducted a study that examined how blood flow to the active leg and whole-body oxygen consumption during single leg cycling compared to double leg cycling. They found that single-leg cycling with a counterweight (designed to make the movement more fluid) caused the same stress on the cardiovascular system as traditional (double leg) cycling, and that blood flow to the leg was higher during single leg cycling.
Additionally, results indicated that the perceived difficulty of single leg cycling was the same as double leg cycling at lighter workloads. This study is important, because it suggests that cycling with only one leg can elicit the same overall cardiovascular responses as cycling with two legs.
So what does this really mean?
This means that you may be able to improve your muscles more with the same amount of effort. When you exercise using one limb instead of two, your body can essentially focus on that limb only. Therefore, those muscles can produce more work and undergo more improvements while demanding the same overall effort and no additional strain on the cardiovascular system. This can benefit anyone who has difficulty sustaining exercise.
Future research may find that this can also benefit heart failure patients who have difficulty supplying oxygenated blood to active exercising muscles.
Burns, K. J., Pollock, B. S., Lascola, P., McDaniel, J. (2014). Cardiovascular responses to counterweight single-leg cycling: implications for rehabilitation. European Journal of Applied Physiology, 114(5), 961-968. doi: 10.1007/s00421-2830-0