Crossfit proves safe and effective in teen study

Aug 3 2015

Dr Narelle Eather

A school-based research program evaluating the efficacy of Crossfit training for teenagers has yielded significant improvements in body composition, aerobic fitness and strength.

University of Newcastle physical activity researcher Dr Narelle Eather, a former national level netball player, conducted the world-first study with Year 10 students at St Philip’s Christian College in Newcastle.

As a new and popular high-intensity exercise regime Crossfit has galvanised opinions among adult gym-goers, some of whom have suffered serious injury from over-exertion. There was no previous scientific data available to determine whether it was appropriate for growing adolescents, deterring schools from adding Crossfit to their curriculum.

“We’ve done studies on high-intensity interval training and on resistance training, and we know cardiovascular fitness is important for teenagers, but no one had ever combined them all in one project,” Dr Eather said. “Crossfit does that in one quick session. We conducted it twice a week, with 15 minutes of hard work, and achieved huge results.”

The findings have been published in the Journal of Sports Sciences.

Dr Eather believes Crossfit’s core-strengthening exercises are sound, providing they’re taught by experienced instructors. Trainer Jamie Johnson from Crossfit Horizons, Sandgate, adapted the St Philips’ course to suit teens, using minimal equipment such as school bags, garden walls or broomsticks.

Among the 96 participants over the eight-week trial there were no injuries other than a few minor grazes. Those in the control group did their PE and sports lessons as scheduled.

“At first the students were complaining about the intensity but by the end they were telling us how much they enjoyed it. They were feeling really good,” Dr Eather said.

Results showed a significant reduction in body fat in the intervention group, with BMI and weight circumference markers improving in both girls and boys. Cardio-respiratory fitness levels rose, most notably among the girls, and there was slight gain in muscular strength despite the low loads employed.

“It showed me that there’s a lot of improvement to make in that age group,” she added.
“As girls enter adolescence there’s a huge decline in sports participation but Crossfit is something that doesn’t require high skill levels and they can do for the rest of their life.

“Fifteen minutes can reap the same benefits or more as an hour of low intensity training so, with a little bit of effort, teachers and parents can get their kids so much fitter and healthier.”

St Philips has since adopted the program as a regular sport option and researchers are now considering trialing it from Year 7 and following the students over a longer period.

*Dr Eather is a member of the University of Newcastle’s Centre for Physical Activity and Nutrition, researching in conjunction with HMRI’s Cardiovascular program. HMRI is a partnership between the University of Newcastle, Hunter New England Health and the community.