Last but not least, always warm up and cool down during each exercise session.
Ninety-four percent of gyms do not offer machines that are accessible by wheelchair, according to recent surveys. But more progressive gyms are taking deliberate steps to be more inclusive to individuals with disabilities and mobility issues by making their layouts and equipment wheelchair-accessible. Before joining a gym, find out if their space and features are accessible to you. Freemotion, for example, is one major brand that makes weight machines that are accessible to both wheelchair and able-bodied exercisers. You may be more likely to find these features in university or hospital fitness facility, many of which offer memberships to the public.
If you have trouble using your hands, wrist cuffs that help secure weights in your hands can help. You may also want to consider using wrist weights or weighted gloves (instead of dumbbells) if this is the case.
If you suffer from a condition that causes your limbs to move involuntarily, try to use strength training machines instead of free weights. Machines (both those with wheelchair access and those without it) are designed to help your body stay in good form and offer more support so that you work in good form and within a safe range of motion.
SparkPeople's Seated Exercises
You can perform almost any strength training exercise from a chair or seated position. Virtually any upper body exercise can be done while seated instead of standing, and you can also strengthen your legs and abs from a chair as well. Many of SparkPeople's exercise demonstrations involve sitting in a chair and several standing exercises for the upper body can be modified to be done while seated, whether you're using dumbbells, resistance bands, or even no weights at all.
The following list includes strength training exercises (and the muscle groups they work) with demonstrations that already involve sitting on a chair. These are great for individuals with limited mobility.
The following list links to exercise demos that you can easily modify to perform while seated in a chair. Each exercise lists the muscles worked and a note for how to modify it to meet your needs (sitting or standing).