My name is Mark Leffler and I’m an ACSM Certified Personal Trainer in San Francisco, CA.
I began my career in the fitness industry in the Greater Boston area of Massachusetts in 2009. Since then I have relocated to the west coast, have met some great minds in the industry, and have had the opportunity to work with many people of diverse backgrounds. Learn more
Principles I train by
Education
WTFO believes in shared knowledge and educates clients, during their training, on the scientific disciplines behind an excellent foundation for your best fitness and wellness.
Safety
WTFO believes in keeping you healthy. You are encouraged to perform exercises that are beneficial to your health, but challenge your will.
Form and Function
WTFO believes maximum benefits, in strength and mobility, are achieved by aligning your training routine with physical demands encountered on a daily basis.
WTFO reviews

Mark is an amazing trainer. My first visit I needed help getting up and down on the mat! Six months later I'm doing straight arm planks! I'm stronger and...
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Bottom-line: All the reviews for Mark are amazing because he's the trainer you want to have. I've worked out with Mark for years and I have no plan to...
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I've been working out with Mark for over a year and a half now, and am really glad I found him. Prior to starting to work with Mark, my workouts were...
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