Watch this short opening clip from the video:

Good, strong, stable knees are so important if you are to maintain a solid lower body base around which your upper body can rotate – especially the knee in that trail leg, often referred to as “the anchor of the golf swing”. A lack of stability here can lead to all kinds of unwanted swing problems.

In the backswing your trail knee must be strong enough to resist the winding of your trunk. When its stabilisers lack the strength to keep it flexed, the trail knee either locks or buckles. (89) Your lead knee must also be strong enough to resist the upper body’s rotation. Only by keeping the lower body quiet can you coil your upper body and create the stretch in the muscles that is needed to hit accurate, powerful shots.

Perform these exercises regularly to improve your knee stability, which will increase both the torque you create in your coil and your ability to maintain your spine angle throughout your swing – a recipe for more consistent ball-striking and more powerful, longer shots.