If you need to get in better shape in a short period of time, you should combine resistance and aerobic exercises to give you the most realistic chance of seeing improvement fast. Trying to build noticeable muscle size in four days will not be a good use of your time or effort. Incremental gains in strength and endurance are realistic goals with the right program.
Varying your routine’s exercises can help you improve fitness in four days
Warmup
Start with a five-minute warmup that includes jumping jacks, in-place jogging, high knee skips, and arms swings and circles to get your blood flowing and your heart rate up. Don’t static stretch!
Bodyweight Exercises
Move to bodyweight exercises such as pushups, situps, chinups, pull-ups, lunges and squats. Perform these exercises slowly up and down, not allowing gravity to do the work for you on the way down. For example, when you do pullups or chinups, pause for one to two seconds at the top of the pull or chin, and then slowly lower yourself with your muscles—don’t drop with gravity.
Dumbbells/Resistance Bands
To add a bit more weight to your exercises, use dumbbells and resistance bands. Perform biceps curls, triceps extension (dropping the weights behind your head, then straightening your arm up, with palm facing forward), flyes (arms out at sides, then weights toward your chest with palms in), presses (laying on your back, pushing the dumbbells up toward the ceiling) and weighted squats and lunges.
Use lighter weights to give you more repetitions; remember, you are trying to build muscle endurance, not necessarily size. Muscle endurance is your ability to perform exercise over a period of time, not just one, maximum lift. Use weights that will allow you to do 10 to 15 repetitions per set.
Aerobic Exercise
Build your cardiovascular strength by exercising at 70 to 80 percent of your maximum heart rate for at least 15 minutes. Calculate your maximum heart rate by subtracting your age from 220 if you’re a man. If you’re a women, use this formula.
If you are out of shape, take a break every few minutes to recover, which will allow you to continue. A good test to see if you are in the aerobic zone and have not elevated your heart rate too far is the “talk test.” If you can talk while you are doing vigorously intense exercise, you are in the aerobic zone.
You can do a cardio workout with any of the following: swimming, jump rope, jumping jacks, cycling, jogging, treadmill, elliptical, rowing machine, exercise bike.
Cool Down
Ever exercise or play a sport, then immediately jump in the car afterward and drive home? Were you stiff when you tried to get out of the car? How did you feel the next morning when you got out of bed? It’s important not to stop intense exercise on a dime so that your heart rate has a chance to go down gradually. Most researcher tend to believe a cooldown and stretch doesn’t help you avoid later muscle soreness, but many people who don’t cool down and stretch after exercise swear they feel stiff the next morning or hours later. Why not take a few minutes to gradually cool down by using the movements you used in your warmup at a walking (vs. jogging) pace. Cool down until your heart rate is lower than 100 beats per minute.
Stretching
Researchers agree that stretching after activity does help promote better flexibility and improved performance later. In order to get the maximum out of your four-day workout, you’ll want maximum flexibility to perform your exercises. If you stretch after each workout session, you’ll not only decrease soreness and stiffness after your workouts, you’ll increase your range of motion and flexibility.
Four-Day Program
If you have a limited amount of time each day, do more resistance work on day one, trading three to five minutes of resistance exercises for three to five minutes more of aerobic exercise each day as you build cardiovascular endurance.