Chiropractic Team

Dr. Allyn Smith, D.C.,C.C.S.P., C.C.R.P.

(Founder and Clinic Director)

Dr. Smith, who grew up in a chiropractic family, is the founder and clinic director of Performance Plus Rehabilitation Center since 1992. His undergraduate studies were at Cedarville College and Iowa State University. His Chiropractic degree is from Northwestern Chiropractic College. He has post-doctorate certifications in sport injuries and rehabilitation. Dr. Smith is an All-American Triathlete and certified USAT level 1 coach.

Dr. Smith is a pioneer in the integration of chiropractic and physical therapy. Performance Plus is one of the few practices in the nation that offers this incredible benefit to their patients in Northwest Missouri.



Dr. Josh Middendorf, D.C.

Growing up on a farm in Northeast Missouri Dr. Josh Middendorf moved away to Northwest Missouri State University to do his undergrad work receiving 2 separate bachelors in science degrees. North West Missouri State University is also where he met his beautiful wife Shanen who is a native of St. Joseph, MO. He earned his Doctorate of Chiropractic Degree at Logan College of Chiropractic in Chesterfield, MO.
Dr. Middendorf has been practicing chiropractic in St. Joseph since 2011. He has special training in Cox-Flexion Distraction, Active Release Technique, and Activator techniques as well as Nutrition.  Neck and back pain, car accident injuries, sciatica, disc herniations, and headaches are just a few of the many conditions that Dr. Middendorf specializes in treating. He is active in a local church congregation as well as the East Side Rotary club and is passionate about the future of the St. Joseph Metro community. Dr. Middendorf and his wife live in the country near Stewartsville. They are foster parents and have adopted their son Isaiah and hope to one day foster and adopt many more children.



Dr. Jennifer Watts

Dr. Watts grew up in central Kansas and began her college career at Barton County Community College where she was a nationally competitive dancer. She finished her Bachelors degree at The University of Kansas before graduating from Cleveland Chiropractic College in Overland Park, KS. Prior to joining Performance Plus she practiced in North Kansas City. Dr. Watts has special training in Flexion-Distraction technique, Kinesiotaping and extremity adjusting. In her free time she enjoys running, yoga, trying new restaurants, and spending time with family and friends


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Dr. Justin Casey, DC

Dr. Casey has recently joined Performance Plus as a Doctor of Chiropractic in the Platte City location. He is a graduate of the Cleveland Chiropractic College in Overland Park, KS. Dr. Casey treats neck, shoulder and back pain, headaches, arm/leg numbness, disc injuries, sprains and strains, degenerative arthritis, athletic injuries, auto injuries and hip, knee and ankle pain. He has completed extra training in extremity adjusting, Activator Methods, and meridian therapy. He was also a massage therapist in Arkansas. Dr. Casey and his wife, Ellen, and their two dogs, Aurora and Daisy now enjoy living in Kansas City. In his free time, Dr. Casey likes camping, geocaching, scuba diving, reading and spending time with his friends and family.