Stephen Valassakis
Founder & clinical director · BSc (Hons), MSc (hons)
Stephen founded GymTherapy to bring the testing standards of professional sport to runners and endurance athletes who train seriously but have never had their physiology measured. He works across the full running pathway — diagnosing the injury, reading the gait analysis, interpreting VO₂ max and lactate threshold data, and building the rehab and training load plan that follows from the numbers.
His clinical background spans English Premier League, English Football League and international programmes, where managing running load, hamstring and tendon injuries, and return-to-running timelines was the daily work. That same framework now underpins how GymTherapy rehabilitates runners: measure first, load deliberately, retest.
- Therapist within the medical team at Burnley Football Club (English Premier League)
- Head Physiotherapist for the Australian Indigenous Roos and Koalas
- Head Physiotherapist / Physiotherapist at Tranmere Rovers FC & Salford City FC (English Football League)
- Consultant Physiotherapist at Oldham Athletic Football Club (National League)
- Private performance and medical consultancy to professional and semi-professional athletes
- Professional and semi-professional Rugby in the United Kingdom and Australia
- A variety of clinical private practice settings in the United Kingdom and Australia
- Running gait assessment, VO₂ max, lactate threshold and RMR testing — protocol design and interpretation
- Consultancy in performance and physiotherapy oversight for sports teams and schools
- Educational roles delivering practical training to students and new graduates in sports rehabilitation and performance
- Running-related injuries — runner's knee (patellofemoral pain), Achilles tendinopathy, gluteal tendinopathy, ITB-related pain, calf and bone stress injuries
- Return-to-running programming after injury or surgery
- Training load management for marathon, half marathon and ultra preparation
- Health and performance data interpretation — translating VO₂, threshold and force plate results into a plan
- Hamstring, muscle and tendon injury rehabilitation
- Complex hip and groin pain
- Orthopaedic rehabilitation — ACL reconstruction, tendon repairs, joint arthroscopy
- Lower back pain, including nerve and disc-related presentations
Matthew Herron
SENIOR Physiotherapist · BSc (Hons)
Matthew works with endurance and hybrid athletes on the problem that ends most running seasons: too much load, applied too quickly, to a tissue that wasn't ready. His professional rugby league background was built around managing high-volume running exposure and repeat overuse injury, and he applies the same load-monitoring logic to runners, Hyrox and hybrid athletes, and gym-based clients.
He takes a data-led approach to rehabilitation — using objective testing to decide when running volume increases rather than working from a fixed timeline.
- Physiotherapist at St Helens Rugby League Football Club (English Super League)
- Private clinical practice and hospital-based physiotherapy in the UK and Australia
- Return-to-sport and return-to-running planning with functional strength rehabilitation
- Athlete testing and objective rehabilitation monitoring
- Running and endurance overuse injuries — tendon, calf and shin presentations
- Training load management and progressive return to running volume
- Hybrid and Hyrox athletes — managing mixed running and strength loading
- Shoulder injuries (acute and overuse)
- Gym-based overuse injuries and data-driven rehabilitation
Achilles and patellar tendinopathy in running and jumping athletes
Return-to-sport and return-to-running testing after soft tissue injury
Sports and athletic injury rehabilitation across running and field sports
Jonathan Parra
Physiotherapist · MSc, BSc
Jonathan's focus is keeping people running rather than resting them. He works with runners and field-sport athletes on hip, groin and lower limb presentations, and on persistent pain that hasn't resolved with rest alone — building the resilience to hold consistent training rather than cycling through the same injury each season. His work in elite youth football involved managing high running volumes in developing athletes, which carries directly into youth and adolescent runners and adult runners returning to structured training.
- Physiotherapist at Brisbane Roar Youth
- Physiotherapist at Football Queensland
- Private clinical practice and hospital-based physiotherapy
- Physiotherapist in private hospital managing pre- and post-operative orthopaedic conditions
- Managing running load in developing youth athletes
- Musculoskeletal injury management with objective, data-driven testing
- Athlete testing and rehabilitation · Anatomy tutor
- Hip and groin pain in running and field-sport athletes
- Persistent and recurring pain in active runners
- Youth and adolescent running load management
- Athletic injuries, particularly football and field-sport related
- Gym-based overuse injuries and orthopaedic rehabilitation
Team sport athlete rehabilitation and return-to-play planning
Bone stress injuries in runners and field-sport athletes
Post-surgical rehabilitation and structured return-to-load planning
ACL reconstruction rehabilitation and return-to-sport testing
James McMulkin
Physiotherapist · BSc (Hons)
James works with runners whose knees are the limiting factor — whether that's persistent patellofemoral pain, a post-operative knee that hasn't tolerated a return to running, or an ACL reconstruction working back toward impact. He uses force plate testing to make return-to-running decisions objective, so progression is based on measured capacity rather than how long ago the surgery was. His care extends past the presenting injury to the strength and movement foundations that let a runner sustain higher weekly volume without breaking down again.
- Musculoskeletal and post-operative rehabilitation across public and private sectors
- Past leadership roles in the National Health Service (UK), including service development and mentoring
- Experience with neurological and complex clients in NDIS settings
- Return-to-sport and return-to-running planning with functional strength rehabilitation
- Force plate testing and objective performance monitoring
- Return to running after knee surgery — force-plate-guided progression
- Patellofemoral (runner's knee) pain and load-related knee presentations
- ACL reconstruction rehabilitation and joint arthroscopy recovery
- Strength foundations for runners and post-orthopaedic surgery rehabilitation
Post-operative rehabilitation and planning for knee joint injuries
Load-related lower limb injuries in runners — calf, Achilles and shin presentations
Movement and strength screening to guide safe increases in running volume
Musculoskeletal and orthopaedic rehabilitation for active adults