SPORT is a physical activity, but serious participants know that games and races are won and lost in the mind.
Success is often achieved not by the most talented player, it is the one with the will to win.
Wimbledon is as good an example of this principle as any.
I like to watch tennis, and have played a little in my time. As with most other sports, I have no more than a moderate ability, but once on the court, I used to run down every ball and reach for every wide shot from start to finish.
In karate I fight, very occasionally competitively, to try to win.
And on the roads, it is only willpower and determination that overcome my very strong instinct to stop running after say seven miles, and carry on to whatever distance I have set myself.
This is not to big myself up - it's the kind of thing every one of you who does sport will recognise it in yourselves.
Andy Murray, Rafael Nadal, Maria Sharapova et al - they have it in spades.
You can actually see the focus and single-mindedness etched on faces and bodies.
No wonder sports psychology and motivational training are big business.
Mental attitude is a positive part of sport and life, but it can also be a trap.
The Italian goalkeeper Gianluigi Buffon recently confessed to battling depression earlier in his career. For us looking in, this talented, successful, rich, good-looking man doing the job he loves admired by thousands should be happy.
But Buffon became so ill he could barely walk on to the pitch.
Former Celtic manager Neil Lennon suffered this mental illness too, and was brave enough to talk about it.
I am not a doctor, nor qualified to advise on depression.
But I do know that in sport and life, mental health is crucial to happiness and personal satisfaction.
And given that this column seeks to encourage self-improvement by me talking about my journey and opinions, I will stray into this territory.
Indeed I often say, not entirely in jest, that as a lawyer I should be entitled to hammer on the door of any of Glasgow's universities and demand a B.Sc. degree in Psychology, so much of that discipline do I and colleagues use in our work. When a client comes in to talk about their issue a solicitor has to hear the words used, but also the words not used, watch body language, facial expression, even dress and personal appearance to get a fuller understanding of what is going on.
In writing over the months, I keep coming up against this mental element, one way or another.
Marathon training included not just winding up my spring and setting off, I had increasingly to plan routes and a schedule around my ability and will to keep going, and develop techniques to ward off exhausted despair.
I even set charitable donation targets to hit myself with both stick and carrot.
My job is to exhort those who need to do better into continuing, or starting, on self-enhancement.
I have said that vigorous sport is a way to better fitness and health, but if you can't do that, then there are all sorts of physical activities to help. Most of us are capable of something. There are many reasons not to change, and only one to make that change.
My late father used to say Beware of the Man With Two Excuses. If something is worth doing, then you need to make an effort of will and not create or exaggerate obstacles.
I have always found that physical exercise benefits my mind and my spirit. Conversely, lack of activity eventually brings me down, a little or occasionally a lot.
I feel that I need sport or at least physical activity to nourish mental health.
For those who are in a bad place mentally, I know that a bit of running or tennis will not be likely to cure instantly or permanently, but it can't hurt, and the process of building up physical standards is usually therapeutic for the soul.
Achievement, even in small steps, nourishes the spirit, and success breeds success.
I know how hard it is to break out of the here and now, to start something new and onerous, especially as it is even harder where there is poor mental health or depression - with capital D or small d.
But then it is even more important to help yourself, no matter how daunting the road may look.
Lao-Tsu, the Chinese philosopher who founded Taoism in the 7th Century, said The Longest Journey Begins With A Single Step. Please choose to take that step.