How does one keep muscles toned and strong without 'bulking up'?

Hi, I was a ballet dancer as well and had the same issue a long time ago. I started lifting weights, very light ones and did many repetitions. The important thing is not to use too heavy ones. those will make you look bigger. So low weights, 4 series of 15 to 18 repetitions for each muscle group, lots of stretching is fundamental and cardio. Sprint hills are great to burn fat, stregthen your muscles. A nutritional program to boost energy, proteins. To help getting rid o any fat and build muscle.

Wow, not being a ballet dancer I thought that dancing ballet would offer these results. However, if you wish to maintain strength and not bulk up while keeping your flexibility I would practice yoga! Yoga will definetly strengthen your muscles (all of them) without bulk and the extra flexibility will help your dancing. Next is nutrition, most of us do not get enough protein in our diet and a gram of protein per pound of body weight works well. I have a hard time with all this protein so I use protein suppliments. Don't neglect your fruits and vegetables along the way and stay off the simple carbs (bread, tortillas, cookies, ect.).

It'd be great to have an idea of your current exercise and nutrition regime :)
In addition to the other answers:
- Include lean proteins in your diet (eg. chicken breast) as nutrition plays a huge role in how you look.
- Bulk up your meals with vegetables (which contain carbohydrates but much less than rice, pasta, bread) and reduce portions of 'carbs' (rice, pasta, etc)
- definitely take up strength training that will help increase your strength. Go heavy but about 60-70% of your absolute heaviest. In my opinion - going lighter and increasing reps improves your endurance but you don't get much strength gains

Light weight based exercise, sensible food intake, regular massage.

The exercise the others have suggested is correct and its also key to look at your diet. I put together sport nutrition programmes to help people like yourself and am happy to have an initial chat to answer your questions properly

try regular swimming , including backstroke...