John Syer: Sports psychologist whose clients included Tottenham's FA Cup winners of 1981 and 1982

If you know what you are doing then you can do what you want." This was a key axiom for the sportsman and sports psychologist John Syer, who has died of cancer aged 72. It was one which he applied as rigorously to himself as to the sportsmen, athletes and business executives he inspired. Co-founder with Christopher Connolly in 1979 of the successful consultancy Sporting Bodymind, at a time when mental training in sport was still looked down on, the two men's techniques were crucial to, among others, Tottenham Hotspurs' FA Cup winning 1981-82 season, the cyclist Chris Boardman's record-breaking pursuit gold medal at the 1992 Barcelona Olympics and the Dutch hockey team's two golds at the 1996 and 2000 Games. Syer, with his quiet passion, human sympathy and attention to detail, was the perfect person to break down old prejudices and inspire new individual and team confidence.

John Syer, born in 1937, was the oldest of four children. While his childhood was happy, his schooldays at Caterham School were not. He said afterwards that the only good thing about them was learning to play hockey and to play it well – the beginning of a distinguished sporting life. He also met there the son of the influential economist, E.F Schumacher, and the great man was to have a profound effect on Syer's own thinking. It was Schumacher who encouraged him to read Colin Wilson's The Outsider and persuaded him to go to France and study French. While the book became, in a sense, his bible, his time at the Sorbonne and Grenoble University, as well as a spell teaching at a lycée in Oran, was the beginning of his love of languages and in particular his love of French culture.

It also introduced him to another of the passions of his life, volleyball, which he first saw being played on a beach in Algeria. He took this passion with him into the army – he did his National Service in Scotland – and to Edinburgh University, where as an undergraduate he played in the University team, later becoming its coach and the first National Director of the Scottish Volleyball Association. As a friend of his put it, Syer was Scottish volleyball.

When not playing that beautiful game in Edinburgh, he was studying French and Italian and completing an M.Phil in linguistics, while reading widely: Proust, poetry, psychology, philosophy and, to lighten the tone, P.G. Wodehouse. He was also using his languages to act as interpreter at sporting conferences around the world. By the age of 30, Syer was a man of original and unorthodox thinking, unlikely to take the world or its traditions at face value.

In 1976, he took a short journey that changed his life, to the Findhorn Foundation on the Moray Firth. This was a place much concerned, ahead of its time, with the organic relationship between people and nature, and – crucially for Syer – the relationship between the individual and the team. It was here that he changed his spiritual direction, a path that led him into training as a Gestalt therapist at the University of California, and it was here that he met Christopher Connolly, the two men beginning to apply the theories of sports psychology that developed into Sporting Bodymind three years later.

It's hard to imagine, 30 years on, how radical Syer's and Connolly's thinking seemed at the end of the 1970s. Steve Perryman, captain of Tottenham when the two men were first involved with the club, confesses that he had never heard of mental training in sport until they arrived and turned the team from a group of talented individuals into a motivated and communicating force.

One of Perryman's most illuminating anecdotes about their methods describes how each member of the Spurs squad was asked to place the others in geographical proximity, depending on how able he felt to trust, or share with, them. Suddenly, players were forced to confront and explore their feelings as well as tactics, and a completely new way of playing together developed.

Syer's and Connolly's 1984 classic, Sporting Body, Sporting Mind, still in print today with its illuminating journey, through body awareness, concentration, visualisation, competitiveness, analysis and confidence, to the ideal team spirit, remains one of the best books written about the art and practice of sporting preparation. And about how to deal with anxiety: Chris Boardman writes in the preface to the 1992 edition that one of the most important things he learnt from Syer was that it is normal to have fears and that they are overcome by acceptance rather than denial.

Syer and Connolly went on to write other books together, including Think to Win, Team Spirit, and How Teamwork works. Syer's reputation at Tottenham led to invitations from Southampton and Watford football clubs, and to requests for his services outside the realm of sport, including Ford, BP, GCHQ and the Cabinet Office. Phone calls would come into the London office from everyone from the managing director of Jaguar to Arsenal's inspirational manager Arsène Wenger. "Send for Syer" had almost become a mantra for so many high-achieving individuals and organisations and, by now, what he and Connolly had pioneered was taken for granted throughout the worlds of business and sporting management.

In spite of his success, Syer remained a very simple man who valued friendship, convivial meals, long walks, landscape, and swimming in waters of all temperatures, including round-the-year-bathing in Highgate's Men's Pond. Until his illness began two years ago, he continued to play tennis – one of his last pleasures was watching the Federer/Roddick final at this year's Wimbledon – and follow the teams and individuals who meant so much to him. He also put into practice, in his brave fight against cancer, the principles of positive thinking he had taught others. At his funeral in Dorset's highest village, the church was full of the people he'd drawn to him over the last 40 years: footballers, singers, athletes, writers, doctors, therapists, volleyball players, swimmers, and friends from all over the world. A winning team, you might say.

He is survived by his sister, two brothers and their families.

Piers Plowright

John Syer, sportsman and sports psychologist: born Caterham, Surrey 10 March 1937; died London 10 August 2009.