The hardest challenge faced by many professional fighters is the one they face on the other side of the ropes, far away from the spotlight, in trying to make ends meet between fights as they strive to reach the point where financial security finally beckons.

For every Floyd Mayweather and Manny Pacquaio earning untold riches from their exploits in the squared circle, there are thousands of fighters whose bank accounts are perennially empty as they struggle to survive.

Take Scotland's John Thain, for example. Since turning pro in 2010 Thain has won every one of his 11 fights, yet he continues to work nights delivering takeaway food or driving a cab between fights to survive.

Not for him the hefty prize money that comes with topping the bill and winning titles. Instead his status as an up-and-coming prospect, fighting on undercards up and down the country, means that every penny is precious.

Cruiserweight prospect Stephen Simmons - who is tipped for a British title sooner rather than later - is in a similar position.

He recently had to pull out of a March 1 fight at the SECC in Glasgow, where he was scheduled to be the chief support for Ricky Burns, defending his lightweight world title against unbeaten challenger Terence Crawford.

With a month to go to his fight against London's Wadi Camacho, Simmons suffered a broken rib in sparring.

Given that he doesn't get paid unless he fights, the financial injury he has sustained is almost as painful as the physical one - and more so when you take into account the fact that for this particular fight Simmons had gone to the expense of a week's training camp in Spain. The money involved is cash he now won't recoup.

Fortunately Simmons receives the support of a couple of local sponsors in Edinburgh and can fall back on whatever income he receives as a sales agent for a nutrition supplements company.

Regardless, with a young family to support, and with him on the verge of headlining his own shows, the setback could not have come at a worse possible time.

It is only when a professional fighter reaches the point of winning titles that the grind of selling tickets is left behind.

Promoters need to put bums on seats and they expect their fighters who aren't household names - who don't command big TV audiences etc - to help them do so by taking an allocation of tickets to sell to friends, family and local supporters.

Coming up to a fight, with the hardship involved in the gym, the gruelling diet for those trying to make weight, the last thing they need is having to sell tickets and collect money for the promoter into the bargain.

Even top fighters aren't immune from the precarious nature of the sport. Ricky Burns prepared for two fights in 2012 that were subsequently postponed.

At his level it is crucial that a fighter gets the very best sparring available, which means bringing in sparring partners from different parts of the country, footing the bill for their expenses and paying them a fee into the bargain.

Likewise, the cancellation of the heavily publicised heavyweight contest between David Haye and Tyson Fury in 2013 would have cost both men thousands of pounds in training expenses, not to mention the fortune each stood to make from the fight itself.

At the opposite end of the scale your average journeyman fighter relies on being able to fight every couple of weeks in order to scratch a living.

His priority is to ensure he survives every fight without being stopped or knocked out - the sport's governing rules would put him out of action for 90 days. The few hundred quid a journeyman gets paid for a fight is a lifeline in many cases.

A typical job for a struggling fighter is door work in bars and nightclubs. This is how a young Frank Bruno made ends meet prior to finding success and financial reward in the ring.

But most fighters would rather find an alternative way to make a living than standing at the door of a bar dealing with drunk patrons late into the night.

Another issue facing a novice pro is getting enough fights. Some only manage to fight three or four times a year, which not only has a financial impact but also affects their sharpness and level of motivation.

No matter how hard you train in the gym - how many rounds you spar and how fit you keep yourself - nothing can replicate fighting when it comes to maintaining a fighter's timing, speed and reflexes.

With the mountain a young professional boxer has to climb, it is not enough for him to want to be a fighter - he has to need it.

This is why they are a breed apart.