Skip to content
Inner Strength Martial Arts

Inner Strength Martial Arts

Duluth, US

Not managed on Matador yetJiu JitsuBoxingMuay ThaiWrestlingMMAKarate

Nobody from the gym runs this page yet, so details come from public sources and may be incomplete. Details last checked on 5 October 2026.

Inner Strength Martial Arts, often shortened to ISMA, is a family-oriented academy in Duluth, Minnesota, founded in 2009 by Professor Robert Mrotek out of a university grappling and kickboxing club. It teaches American karate for children, Brazilian jiu-jitsu, Muay Thai kickboxing, boxing, wrestling and MMA team training, with a bully prevention program for kids and private lessons. Students range from young children to older adults. The academy is affiliated with Ybarra Jiu-Jitsu Academy, is registered with the IBJJF and USBJJF, and represents Kombat Group of Thailand in the region. Its stated philosophy puts family first, school second and martial arts third.

Address
2908 W 3rd Street, Duluth, MN 55806, USA
Sports
Jiu Jitsu · Boxing · Muay Thai · Wrestling · MMA · Karate
Map showing Inner Strength Martial Arts

Training

Affiliation
USBJJF, Ybarra Jiu-Jitsu Academy (Professor Chewy Ybarra), IBJJF, Jiu-Jitsu Global Federation (Rickson Gracie) and Kombat Group (Thailand)
Founded
2009

Programmes

  • Kids classes
  • Beginners' course
  • Private lessons
  • Fight team

Your first visit

Trial
Free first class
Beginners
From age 3

Timetable this week

Monday

17:00Kids American Karate

ages 7+Technique

17:00Kids American Karate

ages 3–6Technique

18:00Muay Thai Kickboxing
19:00Brazilian Jiu-Jitsu

Tuesday

17:00Kids American Karate

ages 3–6

17:00Kids American Karate

ages 7+

17:30Boxing

Cody Bollinger

18:00Muay Thai Kickboxing
19:00Brazilian Jiu-Jitsu

Wednesday

17:00Kids American Karate

ages 3–6Self-defence

17:00Kids American Karate

ages 7+Self-defence

17:30Boxing

Cody Bollinger

18:00Muay Thai Kickboxing
19:00Brazilian Jiu-Jitsu

Thursday

09:00Brazilian Jiu-Jitsu
17:00Kids American Karate

ages 7+Technique

17:00Kids American Karate

ages 3–6Technique

18:00Muay Thai Kickboxing
19:00Brazilian Jiu-Jitsu

Friday

09:00Brazilian Jiu-Jitsu
17:00Kids American Karate

ages 7+

17:00Kids American Karate

ages 3–6

18:00Muay Thai Kickboxing
19:00Brazilian Jiu-Jitsu

Saturday

12:00MMA Team Training

Competition

Sunday

12:00Wrestling

Coaches

  • Robert Mrotek

    Head coachJiu Jitsu · Black BeltMuay Thai

  • Nick Myers

    Coach

  • Ryan Lull

    CoachBoxing

  • Shane Schiff

    Coach

  • McKoy Shaul

    CoachBoxing

  • Cody Bollinger

    CoachBoxing

Contact

Questions about Inner Strength Martial Arts

Where is Inner Strength Martial Arts?

Inner Strength Martial Arts is at 2908 W 3rd Street, Duluth, MN 55806, USA.

Which sports does Inner Strength Martial Arts teach?

Inner Strength Martial Arts is listed for Jiu Jitsu, Boxing, Muay Thai, Wrestling, MMA and Karate.

Can I try Inner Strength Martial Arts before joining?

Yes. Your first class at Inner Strength Martial Arts is free.

When are the beginner classes at Inner Strength Martial Arts?

Inner Strength Martial Arts runs classes open to beginners on Monday 17:00, Monday 17:00 and Monday 18:00.

For the owner or manager

Own or manage Inner Strength Martial Arts?

People already find this page when they search for Inner Strength Martial Arts. Take it over and manage the gym on Matador.

  • Your timetable, prices and contact details on this page
  • Members, payments and drop-ins in the app
  • The Official page mark here and in search
Manage this gym for free

We check you against the listing, then hand it over

Free Matador account · web, iOS and Android

Something wrong with this listing?

If Inner Strength Martial Arts has closed, moved, or the details above are incorrect, tell us and we will fix it.