For as long as I can remember, I've been using my back muscles when I did sit-ups. In fact, I distinctly remember the first time we did them in second grade. After a few reps, it was already so painful that I was having trouble breathing properly. Being eight years old, however, I didn't realize this was a warning sign and assumed it was normal.

Flash forward ten years, and I have almost no strength in my abdominal muscles. I've tried to teach myself to do curl-ups properly, but no matter how hard I try, I can't even lift my head without using my back muscles. Exercise balls are no help either. Even when I concentrate on using my abs to keep myself steady, my back is still doing 95% of the work.

So, in short, I have two questions: Am I at risk for having damaged my back from years of abuse, and how can I work on strength training my abs now?

I have bowlegs. It is quite frustrating because I cannot do exercises that isolate and tone the thighs (lunges, squats, etc). When I do squats, my pressure/force comes from the calves and the knees, but not the thighs. Reason being is that the legs are not properly aligned, and pressure/force cannot go up to the thighs. It even hurts when I do squats because they involve bending the (crooked) knees. Are there any alternative thigh exercises?

I am 18 years old and I am determined to lose a few pounds and tone my body by the end of May. I just began running and I'm starting off by running a mile and hope to work up to a four-mile run four or five days a week. My diet is generally a bowl of cereal in the morning, and a turkey or ham sandwich with some type of fruit and a bottle of water. Dinner is something different every day, but usually healthy. I also have been doing an ab workout for about seven minutes after I run. Is what I'm doing effective? What are your suggestions?

I know most of us have seen the ads to buy various muscle toning equipment that uses electric pulses to "build more tissue" (hypertrophy), and I was wondering what you thought about this way of "toning muscle." Also, if you knew where else I could go to further my research on these sorts of devices?

Thank you very much for your help in advance.

About five days ago while I was doing step aerobics I stepped down incorrectly and injured my foot. It turns out, after seeing the doctor, that I cracked a bone on the outer side of my foot and will have to wear a boot cast for about four weeks. My question is, since I can no longer do aerobics, what other kinds of exercises can I do to help me lose weight? I already do weights, abs, and any other type of leg exercise that don't involve me standing, but I don't feel that this is enough and since I am prone to gaining weight easily, I really want to do as much as I can but in a way that I don't aggravate my injury or make it worse.