High-intensity group workout classes are becoming increasingly popular. It's an effective style of training, with cardiovascular and other benefits, but there has been little research on whether participants are more likely to suffer injuries.
A new study by Mayo Clinic researchers tracked 100 participants in a six-week high-intensity functional training programme and found a statistically insignificant increase in the rate of injury, compared with less intensive workouts.
Findings published in Mayo Clinic Proceedings show an injury rate of 9 injuries per 1,000 training hours during the six-week period, compared with 5 injuries per 1,000 training hours during the six weeks preceding enrolment. Overall, 18% of participants reported an injury during the training period, and 37.5% reported an injury during a training session.
High-intensity functional training uses various combinations of functional movements (movements that require motor recruitment patterns in multiple movement planes across multiple joints) done at a relatively high intensity for a short time. It's part of the broader category of high-intensity interval training, which is primarily endurance or aerobic exercise without strengthening. High-intensity functional training tends to include more strength training and functional movement patterns, the researchers explained.
"These types of classes, which can include ballistic movements such as throwing or jumping with weights, and resistance training with kettlebells or free weights, have become very popular, but other than studies of similar programmes in military training, there are no prospective research studies on injuries that can occur in these classes," said Dr Edward Laskowski, co-director of Mayo Clinic Sports Medicine. "Our findings show a trend toward an increase in injury during the course of a typical class."
Most injuries in the study were related to movements that are ballistic or have an increased risk of injury if not performed with optimal technique.
"Emphasizing proper technique and movement patterns is very important in all exercise, especially strength training," Dr Laskowski advised.
"Though not statistically significant, the sport injury rate was almost three times the rate reported in previous studies," he added. "Hopefully, these results will provide a stimulus for interventions, including focusing on optimal technique and eliminating exercises that are higher-risk when not performed correctly, that will help reduce the risk of injury."