Rather than skipping workouts on busy days, plan a few moves that hit multiple muscles. Start with one or two sets of ten reps each of the following exercises, then move up to three sets when you're ready.
Lunge with Biceps Curl
Holding a pair of 3- to 5-pound dumbbells, stand with arms at your sides. Step forward with your right foot and lower your body until both knees are at 90° angles. As you prepare to press back, curl your arms in front of you, then slowly lower weights as you return to a standing position. Alternate legs and repeat.
Lie on the floor. Place palms lightly behind your ears. Bend your left leg and twist so your right elbow touches your left knee. Repeat on the opposite side.
Step-up to Shoulder Press
With a weight in each hand, stand in front of a 12-inch step. Raise dumbbells to shoulder level. Step up with your left foot first, lift your right leg, and then press the weights overhead until arms are fully extended. Lower the weights to your shoulders and return to starting position, placing your right foot down first. Repeat on the opposite side.