Les Mills Lab

Significant investment in research is an important part of Les Mills’ business and ensures our club partners and their members know that our group fitness programs are safe, effective and powered by science.

We partner with internationally-renowned university research teams to test the effects of our programs on key community health factors such as obesity and heart disease, along with investigations into the motivational and behavioural aspects of fitness. Les Mills Lab research is independent, peer-reviewed and industry-recognized. Find out more

“Our aim is to create life-changing fitness experiences for consumers worldwide. We’ve been revolutionizing the group fitness industry for nearly 40 years and exercise science plays a big part in that.”

- Phillip Mills, Les Mills Executive Director

Our Research

  • DIGITAL AND LIVE INTENSITY

    DIGITAL AND LIVE INTENSITY

    University of Colorado, Boulder, March 2023

    This study compares exertion and enjoyment levels between a live BODYCOMBAT™ class in the gym and two digital formats (livestream and on demand) of the same workout. Participants’ average heart rate was 14 percent higher during the gym class compared to the livestream and on demand sessions. The gym-based workout was also rated as being 13 percent more enjoyable and 14 percent more satisfying. Find out more.

    Published in Frontiers in Sports and Active Living

  • BODYBALANCE AND EXAM STRESS

    BODYBALANCE AND EXAM STRESS

    University of Fraser Valley, January 2024

    This study highlights how BODYBALANCE™ workouts can ease pre-exam anxiety. We found that when the nursing students did BODYBALANCE before their exam, they significantly reduced their anxiety levels. However, that reduction in anxiety didn’t happen when they spent the same amount of time reading their notes before the exam. Find out more.

    Published in Journal of American College Health.

  • LES MILLS CORE AND LOWER BACK PAIN

    LES MILLS CORE AND LOWER BACK PAIN

    University of the Fraser Valley, Canada, 2022

    This study highlights how eight weeks of bi-weekly LES MILLS CORE™ workouts can benefit people suffering from lower back pain. Researchers found the focus on dynamic core stability increased abdominal strength and control, and improved abdominal and back extensor endurance. Find out more

    Published in International Journal of Kinesiology & Sports Science

  • LES MILLS TONE AND POSTPARTUM ANXIETY

    LES MILLS TONE AND POSTPARTUM ANXIETY

    University of the Fraser Valley, Canada, 2022

    With rates of postpartum anxiety on the rise, this important study shows how eight weeks of bi-weekly LES MILLS TONE™ workouts can significantly ease any anxiety and stress new mothers experience. Find out more

    Published in The Health & Fitness Journal of Canada

  • Social identity in group fitness

    Social identity in group fitness

    University of Queensland, Australia, 2019

    This study demonstrates the importance of instructors creating a sense of “we” and “us” in group exercise classes. Instructors who are perceived as part of the ”in-group”, rather than being separated, are more likely to create higher levels of comfort in the class environment and ultimately positively influence attendance and effort. Find out more.

    Published in Psychology of Sport & Exercise

  • Squat load and depth in BODYPUMP

    Squat load and depth in BODYPUMP

    Kathy O’Neill and Stelios Psycharakis, University of Edinburgh UK, 2021

    Squat training in BODYPUMP™ has two key variables: depth and load. This study looked at the effect of these parameters on muscle activation in the lower limb during a typical BODYPUMP squat condition. Depth of squatting had a significant effect on average and peak activity of the quadriceps and gluteus maximus, and peak activity of biceps femoris and lateral gastrocnemius. The effect of load was significant for mean and peak activity of gluteus maximus and lateral gastrocnemius. Find out more.

    Published in Sports Biomechanics

  • BODYJAM research

    BODYJAM research

    DeMers et al, American Council of Exercise, 2020

    This study demonstrates that BODYJAM™ meets the recommended intensity guidelines for exercise programming and is an effective workout for improving cardiorespiratory fitness, as well as for weight loss and weight maintenance. Find out more.

    Published in the International Journal of Research in Exercise Physiology

  • BODYBALANCE/BODYFLOW and Heart Rate Variability Study

    BODYBALANCE/BODYFLOW and Heart Rate Variability Study

    Dr Jinger Gottschall, USA, 2020

    This study provides evidence that the calming effect of adding BODYBALANCE/BODYFLOW sessions to your training results in valuable physical and mental health benefits. BODYBALANCE/BODYFLOW™ is a useful recovery solution for managing the everyday pressures of a busy modern lifestyle resulting in participants feeling more positive, confident and motivated. Find out more.

    Published in Medicine & Science In Sports & Exercise

  • Les Mills BODYPUMP and Athleticism Study

    Les Mills BODYPUMP and Athleticism Study

    Loughborough University, UK, 2019

    BODYPUMP™ generates athletic development; improving strength, power and speed. In addition, total score of athleticism is strongly correlated to lifting ability within the training program. BODYPUMP offers an alternative training mechanism to assist athletic/sports performance. Find our more.

    Published in Archives of Physical Health and Sports Medicine

  • BODYPUMP and Active Aging

    BODYPUMP and Active Aging

    Loughborough University, UK, 2020

    2 BODYPUMP™ classes over a 12 week period generates reductions in TNF Alpha (an inflammatory marker) along with significant gains in functional ability, strength and weight loss in a group of sedentary middle aged individuals. Find out more.

    Published in Heliyon - A Cell Press Journal

  • Les Mills Running and Core Training Study

    Les Mills Running and Core Training Study

    Penn State, USA, 2019

    Three-dimensional core training inherent in CXWORX is shown to improve running performance and be beneficial for improving joint symmetry for injury reduction, deep hip muscle training for knee alignment, and abdominal training for efficient force transmission. Find out more.

    Published in the Journal of Sports Medicine and Physical Fitness.

  • LES MILLS GROUPNESS STUDY

    LES MILLS GROUPNESS STUDY

    Penn State, USA, November 2018

    ‘The group effect’ plays a powerful role in positively influencing a club member’s overall workout experience – their enjoyment, satisfaction, exertion and their intention to return. Find out more.

    Published in Sport, Exercise, and Performance Psychology.

  • PUSH-UP STUDY

    PUSH-UP STUDY

    Penn State, USA, May 2018

    Knee push-ups are shown to be a valuable alternative to toe push-ups for building and maintaining strength as the overall ratio of muscle activation in the upper body - when you do a push-up on your knees or on your toes - is similar. Find out more

    Published in the Journal of Applied Biomechanics.

  • HIIT & OVERTRAINING STUDY

    HIIT & OVERTRAINING STUDY

    Penn State, USA, May 2018

    Weekly HIIT workouts need to be maximized at 30-40 minutes in the maximum training zone to get optimum benefits and prevent overreaching. Find out more.

    Journal publication of this study is currently pending.

  • PHYSIOLOGICAL AND HORMONAL RESPONSES TO BODYPUMP STUDY

    PHYSIOLOGICAL AND HORMONAL RESPONSES TO BODYPUMP STUDY

    Auckland University of Technology, New Zealand, April 2017

    Resistance training - in the form of BODYPUMP - triggers far greater fat-burning and other healthy responses in the body than its calorie count reflects. Find out more

    Published in the Journal of Science and Medicine in Sport.

  • The effects of LES MILLS CORE on quality of life study

    The effects of LES MILLS CORE on quality of life study

    University of New England, USA, November 2017

    Participation in regular LES MILLS CORE improves quality of life and reduces stress. Find out more

    Published in The Journal of the American Osteopathic Association.

  • THE TRIP study

    THE TRIP study

    Penn State, USA, June 2017

    An immersive cycling environment delivers high intensity training without high perceived effort in beginners. Find out more

    Published in the Medicine and Science in Sports and Exercise Journal.

  • BORN TO MOVE study

    BORN TO MOVE study

    Edge Hill University, UK, August 2016

    BORN TO MOVE™ increases motivation, enjoyment and fitness in 10 – 11 year olds. Find out more

    Published by BMC Public Health.

  • group fitness instructor injury survey

    group fitness instructor injury survey

    Penn State, USA, June 2016

    Published abstract: Gottschall, J. S., Hastings, B. (2016). The ACSM physical fitness guidelines for cardiovascular, strength, and flexibility training minimize overuse injury in group fitness instructors. Find out more

    Medicine and Science in Sports and Exercise, 48, 673. doi:10.1249/01.mss.0000487021.61198.dd

  • Developing/testing a motivating communication style

    Developing/testing a motivating communication style

    Curtin University, Australia, June 2016

    A motivational coaching method based on the Self Determination Theory is effective in increasing motivation and adherence in RPM™. Find out more

    Published in the Scandinavian Journal of Medicine and Science in Sports.

  • LES MILLS SPRINT study

    LES MILLS SPRINT study

    Penn State, USA, April 2016

    Six weeks of LES MILLS SPRINT™ increases cardiovascular fitness and body composition in moderately active adults. Find out more

    Published in the Journal of Fitness Research.

  • BODYPUMP and bone density study

    BODYPUMP and bone density study

    Penn State, USA, September 2015

    BODYPUMP™ is shown to be effective at increasing bone density in healthy adults. Find out more

    Published in the Journal of Bone Health and Metabolism.

  • LES MILLS GRIT and visceral adiposity study

    LES MILLS GRIT and visceral adiposity study

    University of Nicosia, Cyprus, January 2016

    Eight weeks of LES MILLS GRIT™ improves body composition and fitness in active adults. Find out more

    Published in the Journal of Sports Medicine and Physical Fitness.

  • RPM effect study

    RPM effect study

    Loughborough University, UK, August 2015

    Eight sedentary participants completed eight weeks of RPM™ with significant changes observed in cardiovascular and metabolic health markers. Find out more

    Published in the Journal of Fitness Research.

  • BODYPUMP squat study

    BODYPUMP squat study

    Penn State, USA, April 2015

    The BODYPUMP™ Rep Effect is an effective strength and conditioning tool. Find out more

    Published in the Journal of Fitness Research.

  • The effect of BODYBALANCE on middle-aged adults study

    The effect of BODYBALANCE on middle-aged adults study

    University of the Sunshine Coast, Australia, November 2014

    Twelve weeks of BODYBALANCE™/BODYFLOW® improved balance and functional performance in middle-aged and older adults. Find out more

    Published in Clinical Interventions in Aging.

  • The effect of BODYPUMP on middle-aged adults study

    The effect of BODYPUMP on middle-aged adults study

    University of the Sunshine Coast, Australia, July 2014

    BODYPUMP™ is shown to be an effective strategy to improve strength and gait speed in healthy adults aged 55 plus. Find out more

    Published in the Journal of Science and Medicine in Sport.

  • LES MILLS GRIT soccer study

    LES MILLS GRIT soccer study

    Penn State, USA, April 2014

    LES MILLS GRIT can be an effective protocol for soccer players and may maximize competition performance while minimizing training time. Find out more

    Published by the Journal of Fitness Research.

  • LES MILLS GRIT study

    LES MILLS GRIT study

    Penn State, USA, March 2014

    Six weeks of LES MILLS GRIT™ increases fitness and reduces cardiovascular risk in active individuals. Find out more

    Published by the Open Journal of Preventative Medicine.

  • LM CORE study

    LM CORE study

    Penn State, USA, March 2013

    Integration core exercises such as hovers and planks are found to increase muscle activation and provide a more effective training stimulus than isolated exercises such as crunches. Find out more

    Published by the Journal of Strength and Conditioning Research.

  • Get Fit Together study

    Get Fit Together study

    Penn State, USA, December 2012

    Thirty weeks of Les Mills’ classes reduces cardiovascular risk in sedentary individuals. Find out more

    Published by the Open Journal of Preventative Medicine.

  • INTRINSIC SATISFACTION STUDY

    INTRINSIC SATISFACTION STUDY

    Penn State, USA, 2012

    Exercisers’ intrinsic satisfaction increases in a group fitness environment when they feel more competent, involved in a group task and encouraged by the instructor. Find out more.

    Published by Frontiers in Psychology.

Our Team

Bryce Hastings, Head of Research

Technical Advisor
Les Mills International

Bryce is literally the brains behind the brawn, leading ground-breaking research and collaborating with internationally-renowned research partners to unearth the latest and most effective fitness techniques.

Drawing from this research and his time in the fitness lab, Bryce ensures that every LES MILLS™program is safe, effective and powered by science.

Conducting research such as the ‘Get Fit Together’ trial and studies into the LES MILLS GRIT™ program, Bryce has illustrated how Les Mills’ programs dramatically decrease fat percentages, lower dangerous cholesterol and triglyceride levels, and contribute to more effective fitness routines. The research not only provides important insights into methods of fitness training, it also offers invaluable evidence and solutions to address growing global government concerns over rising obesity levels.

Bryce became a certified Physical Therapist in 1986 and completed his Advanced Diploma in Manipulative Therapy in 1990. He went on to complete a Masters in Philosophy at Auckland University of Technology where he serves as a Research Associate and lectured part-time for eight years. In 1990, Bryce opened his private physical therapy practice at Les Mills World of Fitness in Auckland, the original Les Mills gym established in 1968 by Les Mills Senior.

He has co-developed research programs on core conditioning, high-intensity interval training and exercise strategies for sedentary individuals, and he has co-authored reports in a variety of fitness and scientific publications.

Dr Jinger Gottschall

Adjunct Associate Professor
Columbia University, U.S.A

Jinger S. Gottschall, Ph.D. earned her doctorate degree in integrative physiology from the University of Colorado at Boulder. She furthered her academic career as a postdoctoral fellow in neurophysiology at the Emory School of Medicine and as an Associate Professor in kinesiology at The Pennsylvania State University. Dr. Gottschall is currently an Adjunct Associate Professor in the Department of Biobehavioral Science at Columbia University.

She was also the founder and co-owner of FITOLOGY, a Les Mills group fitness studio. A passionate advocate for physical activity, Dr Gottschall has dedicated her career to finding programs that promote balanced, healthy lifestyle choices while delivering the results they promise.

DR GILLIAN HATFIELD

Associate Professor, School of Kinesiology
University of the Fraser Valley, Canada

Gillian Hatfield, Ph.D. earned her doctorate degree in Biomedical Engineering from Dalhousie University. Her research focused on developing prediction models for the progression of knee osteoarthritis based on walking biomechanics. She completed a postdoctoral fellowship at the University of British Columbia in the Department of Physical Therapy, where she looked at the effect of exercise interventions on knee loading and muscle activity. She is currently an Associate Professor in the School of Kinesiology at the University of the Fraser Valley, where she teaches Biomechanics and Athletic Injury courses.

Her current research program focuses on the benefits of physical activity in various populations – older adults, people with knee osteoarthritis, people with a history of lower back pain, and postpartum women. As a Les Mills instructor, she is especially interested in the efficacy and benefits of LES MILLS group fitness programs.