Our ability to stand erect as we get older will require that we build stronger bones. Think of bones as the structure or frame of your house. If the structure is weak your house may collapse.
To maintain good posture, stand tall, walk briskly and slow the age related decrease in height, it is critical that we build bone strength on a regular basis. One of the best exercises to preserve and build bone strength is walking. If you are a regular walker and your fitness level is above average it is a good idea to add strength building or weight lifting exercises to your routine.
Some of the best exercises for you to do would be barbell squats, deadlifts, barbell rows or leg presses if you are a beginner. These types of exercises would utilize the largest muscles and bones in your body maximizing your results.
If you are not familiar with working out with barbells (free weights) please get some instructions from a knowledgeable professional. Always use common sense when training to prevent injury. Do not push to the limit if you are just starting out.
Here is a video demonstrating the Barbell Squat