Acute Effects of Beetroot Juice on Locomotor Economy and Capacity in Chronic Stroke

The purpose of this study is to investigate if a beetroot juice supplement can improve oxygen capacity during walking tasks at a submaximal and maximal effort in people greater than 6 months following stroke.

During this study, participants will perform baseline measurements such as walking and balance tests. During baseline testing, participants will be asked to perform a maximal exertion test while walking on a treadmill to determine the speed for a submaximal walking test. One week after baseline testing, the participant will have an intervention session where they drink either a beetroot juice supplement or a placebo. The placebo will taste similar to the beetroot juice and participants may not be able to tell the difference between the two different supplements. After a week, the participant will return to the lab and drink the other supplement. For example, if the participant drank the beetroot juice in the first session, then they will drink the placebo in the second session. During each intervention session, the participant will be asked to perform two treadmill tests, one with submaximal effort and one with maximal effort. After the walking tests, they will drink either the beetroot juice or placebo and have their blood drawn. They will wait at the hospital for 2-3 hours and have their blood drawn again. The participants will then complete the two treadmill tests again. The two intervention sessions will last about 4-6 hours for each session. Participation in the study will last 4-6 weeks including screening and baseline testing.

Oxygen Consumption during steady state walking prior to and following placebo or beetroot juice ingestion

Blood samples taken prior and following ingestion of either the beetroot juice or placebo supplements.

Fastest speed achieved for one minute on the treadmill during the graded treadmill test performed prior to and following placebo or beetroot juice ingestion.

Oxygen Consumption during maximal exertion walking during the graded treadmill test prior to and following placebo or beetroot juice ingestion

Peak heart rate during maximal exertion walking on the graded treadmill test prior to and following placebo or beetroot juice ingestion

Inclusion Criteria: adults aged 18-89 years diagnosis of chronic hemiparesis following unilateral stroke (greater than six months) ability to ambulate at least 0.3 m/s, with or without using an assistive device or bracing below the knee ability to read and understand English follow three-step commands Exclusion Criteria: presence of cerebellar deficits any other neurological or orthopedic deficits that would limit walking ability smoking cannot receive physical therapy for gait-related impairments uncontrolled metabolic, respiratory, and cardiovascular disease

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