Spinal cord injury (SCI) is a devastating condition that often leads to paralysis and multiple health problems such as muscle wasting, bone loss and spasticity. Despite the paralysis, functional electrical stimulation (FES) on the skin surface muscles may produce muscle contractions. People who have had an SCI for a long time (chronic SCI) already use FES cycling to exercise, and it is known that it can reverse muscle atrophy and has a wide range of health benefits. Furthermore, animal research suggests that starting exercise training early after new SCI may promote spinal cord recovery. However, not much is known about early FES cycling in humans. Therefore, the investigators propose to study if early FES cycling could prevent muscle wasting, pain or spasticity, and help with spinal cord recovery.

The study will recruit 36 participants with a new, acute SCI, between 14 and 21 days after their injury into 3 groups. An Early-FES group starts FES cycling early after injury (between 14 and 21 days after injury), and for a duration of 6 months. A Delayed-FES group starts FES cycling 3 months after enrolling in the study, and for a duration of 3 months. A Control group does not perform FES cycling.

This pilot study will allow us to study if early FES cycling, in addition to normal care, has greater benefits on the preservation and recovery of the leg muscles and spinal cord function than delayed FES cycling or standard care only. The results of this pilot study may lead to the development of a larger study with early FES cycling after new SCI.

Spinal cord injury (SCI) usually results in weakness or paralysis in the legs and/or arms, depending on the level and severity of the damage to the spinal cord. In addition, people with SCI often develop several complications in the long term, such as muscle wasting (atrophy), loss of bone strength, pain, and spasticity.

Despite the weakness or paralysis, the muscles in a person with SCI can be activated using electrical stimulation applied on the skin surface of the muscles. This technique is called functional electrical stimulation (FES) and can be used in combination with a bike to perform a cycling movement (FES cycling). People who have had an SCI for a long time (chronic SCI) already use FES cycling to exercise, and it is known that it can reverse muscle atrophy and has a wide range of health benefits. Furthermore, animal research suggests that starting exercise training early after new SCI may promote spinal cord recovery. However, not much is known about early FES cycling in humans, for example, if it could prevent muscle atrophy, pain or spasticity, and help with recovery of the spinal cord. Therefore, the investigators propose to study if early FES cycling may prevent these complications and help with spinal cord recovery.

The study will recruit 36 participants with a new SCI, in 3 groups. The Early-FES group starts FES cycling early after injury (between 14 and 21 days after injury), and for a duration of 6 months. A Delayed-FES group starts FES cycling 3 months after enrolling in the study, and for a duration of 3 months. A Control group does not perform FES cycling. People with an acute, complete or incomplete SCI that resulted in paralysis from the waist down (paraplegia) or neck down (quadriplegia) will be considered. The Early and Delayed FES group will be recruited from the University of Alberta Hospital (UAH) where the FES bikes are available. Participants will be assigned by chance into Early and Delayed FES group. The control group will be mainly recruited from the Royal Alexandra Hospital, where the FES bikes are currently not available. The FES groups will perform FES cycling sessions 3 times per week (up to 1 hour per session) and receive standard care (typically including physical and occupational therapy). The Control group will only receive standard care.

The FES cycling will be performed while the participants are lying in bed using a bed bike, or while sitting in a wheel chair using chair-based bike. Both systems use pedals that are strapped to the feet and an electrical stimulator to activate several muscles of both legs using electrodes attached to the skin.

The following will be measured: 1) the size of the leg muscles and amount of fat in the legs using a CT scanner. 2) strength of the muscles using manual tests and by the electrical signals in the muscle. 3) spasticity by measuring electrical responses in the muscle when stimulated, as well as with clinical scales. 4) strength of the electrical connections between brain and spinal cord. 5) clinical measures such as the spinal injury classification, pain and reflexes. 6) response of participants to the FES cycling program. 7) cost and health care resources for the administration of early and delayed FES cycling. All 3 groups will undergo the same assessments.

This pilot study will allow the investigators to study if early FES cycling, in addition to standard care, has greater benefits on the preservation and recovery of the leg muscles and spinal cord function than standard care only. The results of this pilot study may lead to the development of a multi-center clinical trial with early FES cycling after new SCI, which may have important and innovative implications in the future rehabilitation practice, improving the health, function and quality of life of persons with SCI.

Inclusion Criteria:

• Traumatic or non-traumatic SCI
• Acute onset of SCI
• Able to start FES cycling 14-21 days post injury
• Injury level C1 - L5
• AIS A, B, C, D (ASIA Impairment Scale)
• Medically stable

Absolute Contraindications and Exclusion Criteria

1. AIS D, able to walk without assistive device
2. Unstable spine fractures
3. Unstable fractures/dislocations in lower extremities or pelvis
4. Pregnancy
5. Unable to give consent to participate in the study
6. Contraindications for TMS (Transcranial Magnetic Stimulation).

Relative Contraindications and Exclusion Criteria (Exclusion or Caution)

1. Lower motor neuron injury with insufficient muscle contraction with FES
2. Peripheral nerve or root injury resulting in denervated lower limb muscles
3. History of severe hip or knee instability or dislocation/subluxation
4. Osteoporosis in lower extremities that could result in fracture from cycling
5. Osteoarthritis in lower extremities
6. Limited range of motion in hip and knee preventing cycling
7. History of epilepsy not effectively managed by medication
8. History of heart problems (coronary artery disease / myocardial infarction / congestive heart failure)
9. Implanted cardiac demand pacemaker
10. Implanted stimulators: diaphragmatic, epidural, vagus nerve, phrenic
11. Malignant tumor in stimulated areas
12. Thrombophlebitis or thrombosis in stimulated area
13. Skin lesions or open wounds at any potential electrode site
14. Pressure ulcers that could deteriorate from cycling
15. Spasticity
16. Autonomic dysreflexia
17. Active heterotopic ossification in lower extremities
18. Extreme edema or adipose tissue in legs
19. Any other contraindications to participate in an active exercise program

Person performing electrophysiology assessments will not know group assignment