New research shows that people who engage in high-intensity interval training (HIIT) are at greater risk of injury, especially in the knees and shoulders.
HIIT combines aerobic exercising, weight lifting and calisthenics at maximum capacity, followed by periods of recovery.
It can be effective in improving cardiorespiratory fitness, boosting energy and promoting lean muscle mass and fat loss, but researchers at Rutgers University warned that it also increases the risk of preventable injuries.
"These workouts are marketed as 'one size fits all.' However, many athletes, especially amateurs, do not have the flexibility, mobility, core strength and muscles to perform these exercises," explained Joseph Ippolito, a physician in the Department of Orthopaedics at Rutgers New Jersey Medical School.
For a study published in the Journal of Sports Medicine and Physical Fitness, the researchers looked at records in the National Electronic Injury Surveillance System from 2007 to 2016. They found 3,988,902 injuries resulting from exercise equipment, such as barbells, kettlebells and boxes, or calisthenics, such as burpees, push-ups and lunges, that are common to these programmes. Most injuries involved knees, ankles and shoulders.
Analysis of the data revealed a steady increase of an average of 50,944 injuries per year, which rose alongside the growth in interest in the workouts as determined by the number of Google searches during the years studied. During this decade, they found a significant increase in nerve damage, internal organ injuries, concussions, puncture wounds, dislocations and strains and sprains.
Athletes who perform HIIT without supervision are at increased risk of injury from poor form and muscle overuse, and these types of injuries can lead to osteoarthritis, Rutgers University said.
The researchers recommended that people who are new to these workouts should get medical advice first, and more experienced athletes should learn how to minimise preventable injuries.
Athletic trainers, physical therapists and fitness instructors should ensure athletes are conditioned, use proper form and understand the recovery phase, they advised.