In this current study, the examiners examine some of the mechanisms of how Acute Intermittent Hypoxia (AIH) effects the upper extremity of survivors of spinal cord injury. This is accomplished both with the use of a load cell to determine elbow strength changes and high density grid electromyography (EMG) to record bicep muscle activations before and after bouts of AIH

It has been shown previously that there is an increase in strength in survivors of spinal cord injury after brief bouts of Acute Intermittent Hypoxia. In this study, participants are fitted with a high density EMG electrode on the biceps brachii, and attached to a load cell at the wrist, they are asked to flex and extend their elbow at various levels of intensity. This is performed before and after the 30 minute session of AIH. The investigators hope to identify specific types of motor units of the upper extremity of survivors of spinal cord injury after AIH to help further our understanding of what mechanisms may be causing the known increase in muscle strength post AIH

Inclusion Criteria:

• History of Spinal Cord Injury from C3-T4
• Non-progressive spinal cord injury
• More than 6 months since initial Spinal Cord injury
• Ability to understand and willingness to sign written informed consent

Exclusion Criteria:

• Presence of any of the following medical conditions: Congestive heart failure, arrhythmia, uncontrolled high blood pressure, uncontrolled diabetes mellitus, COPD/emphysema and severe asthma
• Persons with known coronary artery disease, a history of myocardial infarction, or known carotid or intracerebral artery stenosis
• Medical clearance will be required if participant is taking any other investigational agents
• Women who are pregnant or nursing
• Individuals with tracheostomy
• Cannot pursue other research studies which may interfere
• Unable to consent
• Individuals who are not yet adults (infants, children, teenagers)
• Prisoners

Overall participant Data will be reported in publications