Different types of exercise strengthen different muscle groups, for example:
• For arms, try rowing or cross-country skiing. Pull-ups and push-ups, those old gym class standbys, are also good for building arm muscles.
• For strong legs, try running, biking, rowing, or skating. Squats and leg raises also work the legs.
• For abdominal and core strength, you can't beat rowing, yoga or pilates, planks and crunches.