The Feasibility and Effects of Low-load Blood-flow Restricted Exercise Following Spinal Cord Injury

BACKGROUND Spinal cord injury (SCI) represents a major health concern; the World Health Organization estimates an incidence of 250,000 to 500,000 per year worldwide. On average in Denmark we register 130 new cases of SCI per year. SCI is a devastating condition, in which paresis/paralysis of the skeletal muscles below the injury site results in a partial or complete inability to walk, move and/or feel. Concurrent to functional disabilities, infections, lifestyle diseases such as cardiovascular diseases are frequent sequelae due to inactivity and overweight. Affecting primarily younger and previously healthy individuals traumatic SCI also profoundly impacts the mental wellbeing of the patients and also their next-of-kin; quality of life (QoL) suffers and subsequently the risk of suicide for patients with SCI increases by two to five times as compared to the background population.

While a substantial effort is being put into the rehabilitation of individuals with SCI, large gaps in knowledge still exist on this area. Recovery of motor function is of high clinical priority as it is fundamental for improved ADL outcomes.

While various strength training regimens have been shown to increase muscle strength in neurologically intact individuals using near-maximal voluntary effort contractions, few studies have demonstrated similar effects from strength training regimens in persons with SCI. Complications such as atrophy and easily fatigable neuromuscular system with various degrees of spasticity often make these kinds of regimes less practical and rewarding for rehabilitation. Therefore, the addition of low-load blood-flow restricted exercise (BFRE) may prove beneficial as a supplement to traditional rehabilitation. Notable, BFRE is found to increase muscle strength and induces skeletal muscle hypertrophy in healthy individuals. Typically, BFRE is performed as low-load strength training (20-30 % 1 Repetition Maximum (RM)) combined with concurrent partial occlusion of limb blood flow by means of pneumatic cuffs placed proximal at the limb, to restrit arterial inflow to the exercising muscle and preventing venous return. Based on existing scientific evidence and applying pre-exercisescreening for known risk factors such as vascular dysfunction (AD) or prior history of trombosis, BFRE is acknowledged as a safe exercise regime without serious side effects. Previously, the method has shown increased muscle strength and skeletal muscle hypertrophy in addition to improvements in gait and sit-to-stand performance in individuals with various diseases causing reduced mobility.

The aim of this PhD project is to;

1. To conduct a pilot study for investigate the safety and feasibility of low-load BFRE training in adults with SCI
2. To conduct a RCT to investigate the effects of low-load blood-flow restricted exercise (BFRE) on physical function and neuromuscular recovery in individuals with SCI