by Dr Donald Kuah and Dr Brandi Cole

This article has been published in Medicine Today, a peer-reviewed journal for doctors. Read the full article here 

Now in its third decade, CrossFit is a ‘sport of fitness’ designed to help participants achieve the physical activity levels recommended by the WHO for optimal health at any age. However, there are some concerns about injuries related to high-intensity conditioning programs such as CrossFit.

CrossFit began in 1995 when founder and former gymnast Greg Glassman opened the first CrossFit gym in Santa Cruz, California. The first CrossFit affiliate gyms followed in 2003. Seventeen years later, CrossFit is one of the fastest- growing high-intensity functional training models in the world. According to Glassman, CrossFit is a ‘sport of fitness’, defined by its ‘constantly varied, high-intensity functional movement’. Originating as a core-strength and conditioning program, it was designed to achieve competence in 10 fitness domains: cardio- vascular and respiratory endurance, stamina, strength, flexibility, power, speed, co-ordination, agility, balance, and accuracy.

Sport or training?

By 2020, CrossFit has become both a sport and a training method. Some people’s sole purpose for training is to become better at the sport of CrossFit, while a select few are professional athletes, making their living from the sport. Most ‘CrossFitters’, however, are everyday people who attend CrossFit classes to enhance their fitness and health. Physical inactivity is now identified as the fourth leading risk factor for global mortality. In this ‘exercise is medicine’ era, a CrossFit class is considered by many to be an enjoyable option for meeting the WHO global guidelines on the amount of physical activity needed for health and the primary prevention of noncommunicable diseases. The recommended amount of moderate intensity exercise of 150 minutes per week can easily be achieved by attending three CrossFit classes, and the two to three days of resistance training advised can be met by an additional one to two classes per week. Thus, CrossFit serves as a one-stop shop for all the cardiovascular, strength, balance and flexibility training suggested by the WHO for optimal health at any age.

To participate in a class at one of the CrossFit affiliates, an individual may be required to combine weightlifting (snatch, clean and jerk, squats, deadlift) and gymnastic movements (on pull-up bars and gymnastic rings) with a form of cardio exercise (running, rowing, riding or skiing). Other common training methods include the integration of dumbbell and kettlebell movements and skipping rope.

However, only the top few per cent of CrossFit participants would be able to perform these movements exactly as prescribed. The rest would scale or modify the movements to achieve suitable functional outcomes at a less technical capacity or lighter load. This is the feature that makes CrossFit suitable for people of all ages and abilities, including those with disabilities or chronic injuries or impairments that might prevent them from participating in other forms of physical activity.

Risk of injury

A recent study of injury patterns among Dutch CrossFit athletes – via an online survey distributed to all 130 CrossFit gyms in the Netherlands – found the most common injuries were to the shoulder, lower back and knee.6 The only independent variable associated with an increased risk of injury was the duration of previous CrossFit participation, with those who had been participating for less than six months significantly more likely to sustain an injury than those who had been participating for more than two years. Most of the injuries were caused by overuse. This finding was echoed in a similar study conducted in the US state of Florida, in which the most frequently injured locations were found to be the shoulder, knee and lower back.

Although acute injuries do occur in CrossFit, as with any other sport, chronic, insidious overuse injuries are far more common. More often than not, chronic activity-related pain stems from a dysfunction within the kinetic chain and management needs to address all possible deficiencies in the chain, not just the area of pain. For example, shoulder pain may be related to scapular dyskinesis or to cervical and thoracic spine dysfunction, while knee pain may stem from overload secondary to restricted hip range of motion, gluteal weakness and poor core stability. Thus, although any CrossFit enthusiasts presenting to primary care with pain during movement need to have their injury assessed and managed, there are still many activities they can continue to do to fulfil their exercise targets.

References

• Claudino JG, Gabbett TJ, Bourgeois F, et al. CrossFit overview: systematic review and meta-analysis. Sports Med Open 2018; 4: 11.
  
• Glassman G, et al. CrossFit Level 1 Training Guide. CrossFit Journal 2019.
  
• World Health Organization. WHO global recommendations on physical
  activity for health. Geneva: WHO, 2010. https://www.who.int/ dietphysicalactivity/global-PA-recs-2010.pdf (accessed December 2019).
  
• Bergeron MF, Nindl BC, Deuster PA, et al. Consortium for Health and Military Performance and American College of Sports Medicine consensus paper on extreme conditioning programs in military personnel. Current Sports Med Rep 2011; 10: 383-389.
  
• Klimek C, Ashbeck C, Brook AJ, Durall C. Are injuries more common with CrossFit training than other forms of exercise? J Sport Rehabil 2018; 27: 295-299. 6. Mehrab AM, de Vos RJ, Kraan GA et al. Injury incidence and patterns among Dutch CrossFit athletes. Orthop J Sports Med 2017; 5: 12.
  
• Montalvo AM, Shaefer H, Rodriguez B, Li T, Epnere K, Myer GD. Retrospective injury epidemiology and risk factors for injury in CrossFit. J Sports Sci Med 2017; 16: 53-59.
  
• Cools AM, Struyf F, De Mey K, Maenhout A, Castelein B, Cagnie B. Rehabilitation of scapular dyskinesis: from the office worker to the elite overhead athlete. Br J Sports Med 2014; 48: 692-697.