I have a love-hate relationship with this exercise!
I love the effects on leg strength and hip/knee stability.
I hate how much concentration it requires to avoid falling off a table with a kettlebell shaped hole in the head.
The single leg squat and its variations should be one of the first players on your team sheet when designing a workout if you are looking to develop leg strength and power for sport or just functional strength.
Performed properly it will do wonders for developing strength through full range of motion on one leg - something sadly neglected in a lot of strength programs when too much emphasis is put on size and the 'big three' of squats, deadlifts and bench press.
Sport is not performed on two legs or lying on a bench, so why train like that.
These exercises clearly have their place in a strength program but they are not the be-all and end-all unless you're a powerlifter.
It takes time to learn and will require patience and significant amounts of flexibility and mobility work - so don't be impatient.
Here's me wobbling through my best ever in terms of weight!
You'll see me doing it off a high table - this is a good move for tall people who may not be able to get optimal results from working on the floor. Due to lever problems from having legs like a giraffe it can become rather awkward!