INCLUSION CRITERIA
1. Men and women, 19 to 70 years
2. Confirmed cervical and thoracic, AIS A-D who are at least 6 months post-injury and who use a wheelchair as their primary mobility mode
3. Medically stable, able to follow directions
4. Able to provide informed consent.
5. For females of reproductive potential who are sexually active: use of highly effective contraception for at least 1 month prior to Day 1 and agreement to use such a method during study participation and for an additional 12 weeks after the end of intervention.
EXCLUSION CRITERIA
1. Upper extremity musculoskeletal conditions (such as advanced rotator cuff pathology or carpal tunnel syndrome) or neurological disorder that in the assessment of the study investigator would prevent the participant from performing the prescribed arm ergometry.
2. Current fractures in the upper and lower extremity
3. In accordance with the Endocrine Society and ISSAM Guidelines25,52, we will exclude individuals with a contraindication for androgen use:
* History of prostate or breast cancer
* Prostate nodule or induration on digital rectal examination (DRE)
* Prostate specific antigen (PSA) \> 4 ng/ml or \> 3 ng/ml in individuals at high risk of prostate cancer such as African Americans or those with family history of prostate cancer in first degree relatives, unless there has been a negative prostate biopsy within 3 months
* Hematocrit \> 48%
4. Conditions that would render exercise and FES unsafe or unfeasible such as severe autonomic dysreflexia, severe pressure sores, severe spasticity and severe pain.
5. Body mass index (BMI) \> 45 kg/m2
6. Renal dysfunction as indicated by GFR of \<50 ml/min, estimated by using the Modification of Diet in Kidney Disease (MDRD) Study equation, in accordance with K/DOQI guidelines
7. Use of testosterone or other anabolic therapies, including DHEA and androstenedione, or rhGH in the preceding 6 months
8. Active cancer requiring therapy and which may limit life expectancy to less than 5 years
9. Psychosis, bipolar disorder, or major untreated depression
10. Dementia (Mini-Mental Status Exam \[MMSE\] \<24)
11. Myocardial infarction (MI) or stroke within 3 months of entry
12. Pacemaker
13. ALT and AST \> 3 x upper limit of normal
14. Poorly controlled diabetes as indicated by hemoglobin (Hb)-A1c greater than 9.0% or diabetes requiring insulin therapy
15. Blood thinners such as Coumadin, heparin, rivaroxaban (Xarelto), dabigatran (Pradaxa), lovenox (subcutaneous heparin), apixaban (Eliquis) (aspirin, plavix and other anti-platelet agents are allowed)
16. Systolic blood pressure (BP) \> 170 or diastolic BP \> 100 mm Hg
17. Current grade 2 or greater pressure ulcers at relevant contact sites
18. Pressure sores or open wounds on the areas that restricts their participation
19. Because the safety of testosterone has not been established in pregnancy and lactation, we will exclude pregnant or lactating women and women of childbearing potential who are sexually active but are unwilling or unable to use a reliable form of contraception. We will perform a blood test to exclude pregnancy at the time of enrollment.
20. Participation in a structured exercise program currently or in the past 2 months and unwilling to stop the structured exercise program if ongoing at time of screening. Specifically, participation in a structured exercise program, currently or in the past 2 months, that involves progressive resistance exercise training of moderate to high intensity or regular endurance exercise of moderate to high intensity, and unwillingness to stop the structured exercise program if ongoing at time of screening.
21. Inability or unwillingness to participate in the exercise training or the assessments of muscle performance and physical performance
