Dr Sarah Rowell, Chair of UK Athletics and former UK Marathon record holder (2.28) and Technical Consultant to the English Institute of Sport
David has shown tremendous intuition and drive to establish himself within the world of endurance running, not just as a respected coach but also helping athletes with races and training trips abroad. In wanting to help athletes he has actively sought information and advice from the best, not just in the UK but world-wide. He is now in a position where he can use this knowledge to help his growing band of athletes achieve their potential

Bud Baldaro. Former UK Athletics Marathon coach and personal coach to Hannah England, World Championships Silver medallist in 2011 and to many British international runners
As a coach for many years at club, student and area/international level David knows his stuff. Having known David for many years, I never fail to be impressed by his thirst for knowledge of the sport.

A student of the sport for numerous years; he is a true aficionado of the road scene. Passionate and inspired by runners of all ability levels he brings to the table a life long  love of the sport combined with a depth of knowledge and the ability to develop his points in a rational, accessible and comprehensible manner.   He possesses a genuine insight into the both the needs of runners and their patient progression plus of course the very specific demands of the event

Jonathan Solly, Commonwealth Games 10,000 metres Gold Medallist 1986 and 2.12 marathon runner

In the time I have known David... I  have been hugely impressed with his enthusiasm, contacts and depth of knowledge for the sport. He clearly knows his stuff, is great at translating this into meaningful coaching sessions and if I was still running more than 3 times a week, would be delighted for him to have some input into my training   

 Jason Henderson, editor of globally renowned magazine Athletics Weekly, of the book on Improving Marathon and Half Marathon Running

Thanks Gawd, a book on endurance running written by someone who has some real endurance running experience and credentials

Martin Rush, UK and England Athletics Head of Endurance and 1992 Olympic athlete, said of the book

it is a highly readable publication which squeezes a huge amount of information and ideas into a manageable sized book.  Written with a tone and wit that is often lacking in guidance books, it definitely belongs in your road running library.

Dan Robinson, four times Olympic and World Championship marathoner and 2006 Commonwealth Games medallist
David has a huge passion and knowledge of distance running. Having known him for several years, there are few people in British endurance with his dynamism,expertise, commitment and positivity. His willingness to go the extra mile stands out.

Kevin Hickey MBE, former National Coaching Foundation Coach of the Year and former Head of Operations, British Olympic Association
David Chalfen is one of the most committed and passionate coaches I have met. Accepted coaching dogmas are challenged and his thirst for new approaches is ongoing. This couples with a sensitivity for the individual athlete's needs in terms of training/competition and lifestyle. In my opinion, he will undoubtedly be a coaching asset in the UK for the emerging generation of endurance athletes 

Coaches from the Kent Athletics Network at a Flying Coach Seminar/Q+A

We felt very privileged to hear David talk. I think he was by far the best Coaching Development speaker we’ve seen. I loved his down-to-earth approach – he is confident and experienced enough not to feel the need to blind us with science or fancy sports terminology. He used real examples of pacing that I could really relate to over a wide range of abilities and I felt totally connected to what he was saying. We really appreciate the chance to hear someone with his level of experience talk. It’s inspiring stuff.

David Turner, Principal Lecturer in Sports Coaching, University of Hertfordshire

David Chalfen is a highly reflective sports coach who thinks deeply about his coaching practice, and skilfully employs continuing professional development, and extensive professional networking, in order to promote his ongoing coach development and learning. David artfully balances well informed coaching interventions with respecting and encouraging athlete self reliance, in helping to make performance improvements happen. David demonstrates heightened self awareness in terms of his own coaching strengths, responds positively to coaching challenges, and in particular uses writing as a productive means of reflecting upon coaching issues. His coaching expertise has resulted in a natural progression into coach education and mentoring, where he continues to make a positive difference in the life of others.

Matt Norminton, in Canada, in preparation for the Ottawa Marathon, in which he improved his PB from 2.25 to 2.20.52.  Matt states "Having had David look over my own training several times I can attest that he always has good suggestions and practical ideas to improve things. Sometimes this can be as simple as asking me to reevaluate why I am doing something or if I could do things slightly differently. Thanks for all of your help David and I look forward to having you look things over for me as I get ready for my next marathon"