In Stroller Strides class we do bicep curls using our exercise tubing but if you don't happen to have any exercise tubing handy try using small dumbbells, canned goods from your pantry or water bottles to provide the resistance.
If you're using exercise tubing start with your tubing anchored underneath one or both feet and hold the handles in your hands. For all other "weights"- place one of whatever you're using in each hand and stand with your feet shoulder-width apart or one in front of the other in a split stance. Your palms should be facing forward/up with your abdominals pulled in tight and shoulders rolled back and down.
Squeezing with your biceps, keeping your elbows glued to your side, curl both arms up towards your shoulders, hold for 1 second, and slowly release. Repeat 12-15 times for 3 sets. Keep control of the "weight" at all times. Be careful not to swing your arms or arch your back... that's cheating and you might hurt yourself that way.
Please do not attempt this if you have not yet been cleared by your physician to exercise!