Strange as it may seem, I regularly get asked this question and actually, it is a great one to answer.
Is Mo Farah fitter than Usain Bolt? Is Wayne Rooney fitter than Andy Murray?
In many ways there is not a correct answer.
Fitness is many things to many people and depending on your likes, dislikes and goals you will have different requirements.
However, fitness can be broken down into many components.
To be truly fit we should be strong across many areas and we should regularly train to improve in every way.
The main three components of fitness are cardiovascular fitness, strength and flexibility.
Cardiovascular fitness refers to the strength of the heart and the ability for the heart to work hard and recover from work quickly.
However, Cardiovascular fitness can be broken down into two broad areas of specificity: endurance is the ability to work at low to medium intensity over long duration, like ironman trialthletes or marathon runners.
Stamina is the ability to work at very high intensity in short bursts over a medium duration, like a rugby player or many other team sports.
In reality these are very different types of activity but both are important to us and both need to be trained and improved.
Placing activities like cycling or fast walking in your weekly programme, alongside team sports or circuit training, will adapt both these cardiovascular components.
Strength is the second of the major fitness components.
However, there are many different types of strength.
Is strength having big muscles like a body builder, is it about having the speed and power of a boxer, is it about having the amazing body weight strength of a climber, is it about having lean and toned muscles like a body model or the postural strength of a ballet dancer?
Once again, in reality, it is actually all of these things.
We need to have incredible muscle strength to maintain the structure of our skeleton and to live a long, healthy and active life.
All too often, we use age as a reason as to why we can't do certain things anymore.
It is more often strength than age that is the reason.
We need to be able to lift and carry large weights: we should also be able to lift, push or pull our own body weight over and over again.
There are very few forms of exercise that allow us to do all of these things in one go. Therefore we need to build lots of different activities into our training to capitalize on all of these requirements.
We need to do strength training with weights, we need to build power with activities like kettlebells, we need to use our own body weight with activities like climbing and we need to use the large and small postural muscles with activities like Pilates. Only by pushing the body in all directions can we really be strong.
The final fitness component is flexibility. I prefer to look at this as mobility, rather than just flexibility.
Mobility to me is about working flexibility and strength together and is about creating large controlled range of motion around all joints, as a result reducing strain on the joints and therefore pain or inflammation.
There is no point being strong if you are not mobile as it will result eventually in injury.
There is no point having amazing cardiovascular fitness if you lack mobility as again, eventually it will lead to injury.
Most of the pain and injuries we see in our clinics are from lack of mobility from some muscles being strong and others being weak, some being long whilst others are short and the tension at the joints, as a result, being great.
It is vital that we build joint protection and muscle balance into our weekly routine by using mobility drills, looking at strength exercises that increase our range of movement, stretching, rolling, doing activities like yoga and having regular treatment from physios, osteopaths or soft tissue work done by good quality sports massage specialists.
Ultimately, true fitness is about regularly training all of these aspects of fitness and about having as much diversity within our training as possible.
It is about being as active as possible and maintaining great mobility so that we reduce the effects of ageing.
It is also about regularly trying new things and pushing the body in different directions.
The human body is an incredible thing and adapts very quickly, therefore the way you train the body always has to be one step ahead.