Whether you're already a fitness fan, or you're getting involved with a healthier routine for the first time, the chances are that you already know how important cardiovascular exercises can be to your fitness regimen. Unfortunately, these workouts can also be particularly painful for people who suffer with aching joints. Only certain cardio workouts for people with bad knees will be effective at improving your overall health, and reducing your chance of injury.

The following options may offer a pain-free solution to your cardio needs, but remember to check with your physical therapist or doctor before you get started with any new workouts.

1.    Step-Ups

Step-ups are ideal ways to strengthen the muscles in your legs, and get your heart pumping at the same time. In cardio workouts for people with bad knees, these exercises work the hamstrings, quads, and glutes.

Start by standing in front of a bench or staircase, and place one foot flat against the bottom step. With your knee situated directly above your ankle, press your weight forwards onto the heel of your elevated foot, and lift the opposite foot away from the floor. Carefully place your foot back on the floor and repeat with the opposite leg after you've finished ten reps. For better results, try doing curls with dumbbells every time you take a step.

2.    Partial Squats

Although full squats can be one of the worst cardio workouts for people with bad knees, partial squats are actually more beneficial than you might think. To get started, position your feet around a shoulder's width apart, and point your toes forwards. Tense your core while dropping your upper body as far as you can. Keep your knees behind your toes during the movement. Make sure you use a good knee compression sleeve with this exercise - and never workout without a partner.

3.    Calf Raises

Ideal for working out the lower leg muscles, these calf raises form a vital part of many cardio workouts for people with bad knees. Stand up straight with the balls and toes of your feet on a flat surface. Keeping your hips, ankles, and shoulders, perfectly aligned, point your toes forward, and lift your heels slowly, before lowering them at the same speed. The slower you raise and lower your body, the better your workout will be.

4.    Scissor Kicks

To work your hip flexors, abs, and thighs at the same time, lie flat on your back with your arms by your sides and your legs together. With your forearms against the ground, lift your legs around six inches, and your shoulders away from the floor by about one inch. Hold the position for as long as you can, and spread your legs apart, bringing them back towards one another, then cross one over the other. One completed movement translates to one rep.

5.    Swim

Finally, an exercise that forms a cardio workout of its own, swimming can be an ideal exercise for people with aching knees. As a versatile and low-impact sport, it's useful for both burning calories, and reducing the amount of stress you place on your limbs. Just remember that it's crucial to keep proper form, especially when kicking your legs during strokes.