You need more space when completing the walking lunge.
The chair lunge and walking lunge are both compound strength-training exercises that work the major muscles in your lower body. They're similar to the squat, except that they require each of your legs to work independently. While the chair lunge and walking lunge have numerous similarities, including the muscles they work, the chair lunge is typically slightly more challenging than the walking lunge.
Chair Lunge Technique
When you perform the chair lunge, which is also referred to as the split squat, you work one leg at a time. Once you're finished with the set, you switch legs. Stand with the chair behind you, and pick up and place one foot atop the chair so that you're in a staggered stance with your back foot elevated. Keep your torso erect as you bend your lead knee to lower your body toward the floor. Once your lead knee is bent to 90 degrees, extend it to raise your body back up. Go right into the next repetition, continuing until you're finished with all the assigned reps, then switch legs.
Walking Lunge Technique
During the walking lunge, you alternate legs. Find a location where you have space to move forward. Start with your feet set shoulder-width apart, and take a large step forward with your right foot to place you in a staggered stance. Keep your torso erect as you bend your lead knee to lower your back knee toward the floor. Extend your lead knee to raise your body back up, finishing by bringing your back foot up so that it's beside your lead foot. On the next rep, step ahead with the opposite foot.
Both the chair lunge and walking lunge work the same muscle groups. The gluteus maximus, which is the major muscle in your buttocks, handles the greatest percentage of the load. It extends your hips, or pulls your leg back behind you. Also in use are your quadriceps, which are a collection of four muscles at the front of your upper thighs that are responsible for extending your knees. The gastrocnemius, one of the two major muscles in your calves, plantar flexes your ankle joints. According to ExRx.net, the walking lunge requires more of your core muscles to get involved to keep your torso erect. While the erector spinae in the back is active during both exercises, your obliques are only activated during the walking lunge.
Modifying the Exercises
During the chair lunge, a greater percentage of your body weight is placed on your lead leg, making that the more difficult of the two exercises. In addition, the chair lunge requires you to work the same leg for repeated reps, meaning you'll likely need fewer reps to reach fatigue. Both exercises can be completed with just your body weight as resistance. However, you can increase the difficulty of each exercise by holding a pair of dumbbells or placing a weighted barbell on the back of your shoulders. The further you split your feet, the more you work your gluteus maximus. The closer your feet are, the more emphasis there is on your quadriceps.