Stretch before and after
To help alleviate the muscle pain that you feel after raking leaves you need to stretch both before and after your raking sessions. Raking can be an aerobic activity, just like when you do cardio at the gym. When stretching, try to remember that you use your whole body when you are raking. It would also be of benefit to warm up a little prior and do not start when your body is cold.
Use proper body position
Keep your legs slightly bent, keep your weight centered and your back straight. Reach with your arms and not with your back. Avoid twisting by shuffling your steps and think about moving from your hips in order to reach the area around you. Do not over extend by keeping your strokes short.
Switch the lead arm and leg
Raking is a repetitive motion that can exhaust your muscles. By switching your lead arm frequently you can help alleviate this problem.
Do not decide that you are going to go out and handle a large accumulation of leaves in one shot. The best-case scenario is to break it up over several days so that your muscles will not be overworked. If this is not possible, try to take breaks and spread it out over the day. Make sure that you stay hydrated. Dehydrated muscles are more prone to strain.
Proper rake size
Use a rake that is properly sized for you. Rakes with thicker handles can decrease fatigue in your hands. There are also several ergonomically shaped rakes that can assist with strain on the spine.
Bend at the knees and lift with your knees and not from your back. Keep the weight reasonable for your fitness level and strength.
Work smarter, not harder
Dry leaves are lighter than wet leaves. While it may not seem like a big deal while raking it will become a lot bigger issue when you have to lift the bag.