The best exercises to strengthen and stabilise your knees

Having weak knees is an injury waiting to happen. 

Despite the hip or even the ankle being far more complex in terms of biomechanics, it's more often than not the knee - that hinge that sits between them - that causes problems for people. Injury, osteoarthritis, localised pain can all impact quality of life.

A lot of the problem comes from our misunderstanding of this crucial joint.

Since the 1970s it was perceived by many in the sporting and medical industry that the knee should never pass the toe in loaded exercises. 

Fortunately, many top coaches, trainers and medical professionals are starting to wave this in light of a better understanding of the knee. To fully utilise and bulletproof this joint, you need to focus on stability, range of motion, and strength. With these three anchors we will reduce the risk of injury and pain so that we can move freely and without pain late into life.

Range of motion

A healthy knee joint must have full range of motion in both flexion and extension (bending and straightening the knee), and a small amount of rotation. 

As a general rule, the knee must be able to fully lock out (extension), and also bend (flexion) all the way to the glutes. Without this range of motion, daily activities and exercise will be severely limited and the knee will have a far greater propensity for injury, pain and osteoarthritis. Because the knee joint acts as a hinge between the hip and ankle joints, it's important to consider the range of motion in these joints also. 

For example, that tight, achy ankle from a bad sprain six months ago will create massive limitations on the amount you can have your knee extend past your toes, especially in activities such as squats, lunges or even just getting up off the couch.

Strength where it's needed

Not only does the knee joint need adequate range of motion, but it also needs to be stable when going through this range. This is where the quadriceps and hamstrings come into play. 


Strong quadriceps equal more powerful knee extension and ensure the patella tendon is not overworked or put under too much shock load. Some simple but effective quadriceps strengthening machines include the leg press and leg extension machine. 

More advanced exercises include walking lunges, front squats and frog squats. 

Isolate your movements

Strong hamstrings equal more powerful knee flexion and helps protect the ligaments of the knee such as the ACL and PCL. Some simple but effective hamstrings strengthening machines include the lying and/or seated hamstring curl and advanced exercises like Romanian deadlifts, swiss-ball curls, and Nordic curls are hugely beneficial.

As a general rule of thumb, the knees want to move in line with the feet; if they deviate regularly outside of this line, or when under heavy load, then this is a tell-tale sign that there are strength issues that need to be addressed.

Two of the main muscles that assist this are the gluteus medius and the vmo (vastus medialis oblique). The role of the gluteus medius is to act as a stabiliser of the pelvis and can be strengthened with banded monster walks. The vmo stabilises the patella and controls its tracking. It can be strengthened by exercises which straighten the knee under load such as leg extensions or split squats.

Gain a stable stance

The knee hates violent shock-load and twisting. These movements are the main causes of common injuries such as acl (anterior cruciate ligament) tears. Stability for the knee starts at the ground up, ie the foot.

When performing any leg exercises, try to make sure you maintain three points of contact with the foot: create pressure in the spot just before the little toe, big toe and right through the heel. This has now created a tripod foot of sorts and enables the foot to transfer force effectively through the floor. 

When it comes to stability exercises, go straight to loaded, single-leg movements. These will have much more carry-over to real world demands. Single-leg Romanian deadlifts, pistol squats and single-leg step downs are all your best friend, or worst enemy depending on how you feel the next day.

Upstream of the knee lies the hip, which also needs adequate stability. The knee will have no chance if you're unable to set the pelvis in a neutral position. This applies to exercises like the single-leg Romanian deadlifts plus some great core exercises to assist, such as dead-bugs, bear crawls and rotating planks to name a few. Also has the added benefit of carving out a chiselled midsection.

A body that moves freely, and without pain, is the ultimate goal here.Follow these guidelines and you are well on your way to bullet-proofing your knees to perform at their best well into your senior years.