Be Nice.
Train Nasty.

The Mind is Primary.

Join Team Nasty Learn More

Are you ready to be the best version of yourself?

My mission is to help my clients feel their absolute best. To me, fitness is the ultimate keystone habit. I believe that once our fitness is dialed in, many other facets of our lives respectively fall into place. With a fit lifestyle and healthy diet, we experience a sharper intellect, a boost in mood and self-confidence, and more energy to crush every aspect of our busy lives. My clients share one thing in common: they may be nice on the outside, but they train nasty in the gym.

Private Sessions

Perfect if you’re located in NYC and want focused, one-on-one attention to achieve your fitness goals.

Learn More

Online Training

Each week, you’ll receive three new workouts: 1 upper body, 1 lower body, and 1 full body

Learn More

21 Day Challenge

The most proven fat loss strategies come together for only 25 minutes each day!

Learn More


  • I have become whole; under the guidance of Coach Jayson Leisenring What I mean is that, for the first time in my life I feel in touch with myself both mentally and physically. The rigorous training coach has put me through has pushed my body from 175-130 pounds lighter. He shows me that goals can be reached and renewed. His Circuit training will have you gasping for air as if your head was held deep underwater for an hour, and then after a million thoughts later of how you may have convinced yourself that you’re dying, and you need to stop. You’ll begin to thank yourself, and realize that for the first time in your life you have conquered the voice that says, “I cant”.

    Alexander Salazar
  • l’ve been taking Coach Jayson’s classes for about a month now, and I LOVE them.
    These are high intensity interval training circuits where we use weights, ropes, heavy bags, jump rope, medicine balls, our bodies, etc. in such a creative, non traditional manner, mixed in with striking and kicking martial art techniques. Coach Jayson designs his workouts so that whether you’re training for a a fight, want to increase your fitness levels, are looking to lose weight, or even if you have never worked out before, you are still able to challenge your body and get an amazing workout.

    Parul Laul
  • I’m someone who has waisted so much money on countless gym memberships due to the fact that I never went – mostly because I don’t know how to motivate myself or know what to do to achieve the results I want. Jayson has not only changed the way I see fitness but has changed my life. The results I’ve seen since starting with him in January are a true testimonial to his talent. I’m also now a morning gym person which is the most shocking!

    Jon-Michael O.
    Manhattan, NY