This exercise is done with both legs but it is used to help you improve the balance, stability, and strength of a single leg. Training one leg at a time has a lot of benefits.

EQUALIZE THE STRENGTH OF EACH LEG

Having one leg that is stronger or more stable than the other leg can cause you to use the legs differently without being aware of it - you begin to favor or compensate for the weaknesses. And many of us do commonly have a stronger and weaker side. For me, my right leg is my stronger leg.

When we have this imbalance, we may begin to use one leg more than the other when going up and downstairs, getting up off of the toilet, or squatting down. Or worse yet, we begin to avoid squatting down, we may notice that we are “pulling” ourselves up the stairs on the handrail, or we begin to push ourselves out of a chair using our arms. Over time the leg will get weaker because it is not being used as much. 

Our arms are much smaller than our legs so doing jobs with our arms that are supposed to be designated "leg jobs" is a jerry-rigged idea.

So I guess we can say one reason to do this sort of exercise is so that we don't turn leg jobs into arm jobs.

Training each leg separately allows us to notice "oh, wow I can easily do 10 reps on this leg, but my other leg can barely eek out 6 reps" even though you're even mentally cheering it on like 'c'mon leg, you can do it, rep 7 here we go, let's get after it!'

Once we're aware of this difference, then we can purposefully spent a little extra time doing more sets with the weaker leg to bring it up to snuff.

IMPROVE OUR BALANCE

Single leg training will challenge your balance. Our balance tends to get worse with age, this is just a fact says Carol, the physical therapist whose taught me everything I know.

Tell me about it Carol. I could see it getting worse, but even just turning 40 myself, things are all well and good on nice even ground, but the second there's a crumb under my foot it's like watch out floor.

If you're in your 60's you might be like "Rayzel, even if there's no crumb, I still practically die if I don't have both my feet under me."

We are going to change this ladies! You and me both.

The good news is, you can easily improve your balance by working on it. A well-designed exercise program will include single-leg movements to challenge your balance.

IMPROVES JOINT STABILITY

Single leg exercises help to improve the stability of our joints. An unstable joint has too much movement. This movement can lead to damage to the joints - like osteoarthritis (or OA).

It is important to work the muscles that cross the joints and keep them stable. The split squat is a really good exercise for strengthening the muscles that cross the ankle, knee, and hip. 

HEATHY, STRONG QUADS = HEALTHIER KNEE JOINT = LESS KNEE ISSUES

The quadriceps are responsible for the health of your knee joint.

The kneecap is actually IN the tendon from the quadriceps muscles. The muscle guides the kneecap in a little groove that it moves in. If the muscles of the quadriceps are not trained to hold and move the kneecap correctly - it can cause damage to the back of the kneecap.

Split squats are perfect for training the quadriceps to move the kneecap correctly. 

SPLIT STANCES ARE COOL

Split stance positions are a great way to make exercising our leg muscles at home effective, without having to use super heavy weights at the gym in order to fatigue the muscles.

Because our larger lower body muscles are just so.....well, large, they are naturally pretty strong, and that can make it a challenge to find ways to fatigue these muscles at home without those heavier weight. The split stance really helps with this, because we have a lot more of our bodyweight on one leg now (ie the "heavy weights we are using is not a machine or large dumbbells, but rather our own bodyweight now!), rather than both legs spreading our weight equally. This position is also a great segway to eventually being able to do single leg movements.

The split squat exercise works the front leg the most - especially the front of the thigh (quadriceps) and the muscles of the side and back of the hip (gluteals).

You will bend the ankle, knee, and hip of the front leg to lower yourself down until your thigh is parallel to the floor (so we have 3 joints moving around here!) That means we're doing a compound exercise. Compound exercises can take a little more work to learn properly because we're moving in multiple places on our bodies, BUT they are great to do because they work more muscles at one time.