Ischaemic Preconditioning and Upper Body Exercise Performance in Persons With Spinal Cord Injury

Details

Once participants have signed informed consent, they will undergo the following procedures: A. Randomisation into IPC vs Sham group B. Researcher will offer a suitable time to perform the study recording. C. Participant will be requested to spare up to 3 hours to complete the intervention. D. Intervention session (IPC / Sham): Participant arrives. On arrival, after 10 minutes of seated rest, baseline heart rate and blood pressure (BP) will be measured. Two electrodes will be placed on the lateral triceps head for Electromyography (EMG) assessment during the triceps exercise capacity tests. To determine maximum voluntary contraction (MVC), a warm-up of 2 contractions each of a participant-estimated 50% MVC, 70% MVC, and 90% MVC, will first be performed. Participants will then undertake up to 5 maximal isometric contractions of the triceps, from which the MVC value will be obtained (average of the best 3 contractions). Following a rest period (5 minutes), a metronome will be used to give participants the cue to rhythmically isometrically contract their triceps (60 contraction-relaxation cycles/min) to a target value of 70% MVC. The time to task failure and ability to complete the exercise will be noted. Participants will report Rating of Perceived Exertion (RPE) using Borg's scale immediately after completing the exercise. Before and after the exercise, a capillary blood sample will be obtained from the earlobe for assessment of blood lactate concentration. Heart rate will be measured throughout. Repeat BP measurement. 30 minutes rest. Repeat BP and heart rate measurement. The MVC will be determined again, followed by a 5-minute rest. Proceed to intervention - 4 cycles of 5 minutes of IPC / Sham followed by 5 minutes of reperfusion. (Total 40 minutes). IPC intervention - This will involve tying the cuff of a manual BP apparatus around the upper arm and inflated to a minimum of 200 mmHg, or a pressure of 60 mmHg above the resting systolic BP, whichever is higher. The inflation will be maintained for 5 min followed by cuff deflation lasting 5 min. The cycle will be repeated four times. The Sham intervention will be delivered with the manual BP cuff tied to the upper arm. The cuff will be inflated 30 mm Hg below the diastolic BP for 5 min followed by deflation for 5 min. The cycle will be repeated four times. 10 minutes rest. Repeat pre-exercise capillary blood sample for determination of blood lactate concentration. Repeat 5 maximal isometric contractions of the triceps. Repeat a rest period of 5 min. Repeat rhythmic isometric triceps contraction exercise. Again, time to task failure and ability to complete the exercise will be noted. Repeat reading of Borg's Rating of Perceived Exertion (RPE) scale, post-exercise capillary blood sample, BP and heart rate measurements. Recording of adverse events and numerical pain scale, open ended discussion around perceptions and tolerability of IPC. 15 minutes rest. Repeat BP and heart rate measurement. Exit from study.